<PAGE>   1
                                                                   EXHIBIT 4.5


                                NOTARIAL DEED



                        SALE AND ASSIGNMENT AGREEMENT
                                (VINTRON GMBH)





Negotiated at Basel/Switzerland this 19th (nineteenth) and 20th (twentieth)
day of May 2000 (two thousand).


Before me, the undersigned Notary Public



                                STEPHAN CUENI


at Basel/Switzerland appeared today:


1.    Dr. Kerstin Schweizer, born September 17, 1970, attorney-at-law, German
      citizen, with business address at D-60311 Frankfurt/Main,
      Bethmannstrasse 50-54, and private domicile at D-61440 Oberursel, Alt
      Konigstrasse 80, identified by his German Personalausweis,


      according to her declarations acting not in her own name, but in the
      name and on behalf of


      Vinnolit GmbH & Co. KG, a German limited partnership with head office at
      D-85737 Ismaning, Carl-Zeiss-Ring 25, to be registered with the
      Commercial Register at the Local Court of Munchen under Section A,
      presenting a written power of attorney dated May 17, 2000, a true copy
      of which is attached,


                                        - hereinafter referred to as "Buyer" -



2.    Dr. Ralf Christner, born January 7, 1965, attorney-at-law, German
      citizen, with private domicile at D-60318 Frankfurt am Main, Wielandstr.
      61, identified by his German Personalausweis,



<PAGE>   2

                                                                             2


      according to his declarations acting not in his own name, but in the
      name and on behalf of


      Celanese Chemicals Europe GmbH, a German limited liability company with
      head office at D-60439 Frankfurt am Main, Lurgiallee 14, registered with
      the Commercial Register at the Local Court of Frankfurt am Main under
      No. HRB 42088, presenting a written power of attorney dated May 10,
      2000, and an extract from the Commercial Register dated March 8, 2000,
      true copies of which are attached,


                                       - hereinafter referred to as "Seller" -






The acting notary asked the persons appeared prior to the notarization whether
he or any of his partners acts or acted in the matter to be recorded for any
of the parties of this deed outside his or, as the case may be, their notarial
function (Section 3 para. 1 No. 7 German Recording Act (Beurkundungsgesetz)).
The answer was negative.


The persons appeared requested this Deed including its Schedules to be
recorded in the English language. The acting Notary Public who is in
sufficient command of the English language ascertained that the persons
appeared are also in command of the English language. After having been
instructed by the acting Notary, the persons appeared waived the right to
obtain the assistance of a sworn interpreter and to obtain a certified
translation of this Deed including the Schedules hereto.


The persons appeared asked for the Notarization of the following:



                        SALE AND ASSIGNMENT AGREEMENT


                             entered into between


                       Celanese Chemicals Europe GmbH,
                     with its seat in Frankfurt am Main,


                                     (hereinafter referred to as the "SELLER")


                                     and




<PAGE>   3



                                                                             3

                            Vinnolit GmbH & Co. KG
                          with its seat in Ismaning,


                                      (hereinafter referred to as the "BUYER")


              (the Seller and the Buyer hereinafter also referred to singly as
                                the "PARTY" and collectively as the "PARTIES")




<TABLE>
<CAPTION>
TABLE OF CONTENTS                                                                   PAGE
<S>                                                                                <C>
   PREAMBLE............................................................................4
   SECTION 1 DEFINITIONS...............................................................5
   SECTION 2 SALE AND TRANSFER; EFFECTIVE DATE AND CLOSING DATE........................8
   SECTION 3 CLOSING CONDITIONS.......................................................10
   SECTION 4 INFRASERV AND OTHER CONTRACTS CONNECTED TO CELANESE......................12
   SECTION 5 CONSIDERATION............................................................14
   SECTION 6 ANNUAL ACCOUNTS..........................................................15
   SECTION 7 REPRESENTATIONS AND WARRANTIES OF THE SELLER.............................17
   SECTION 8 REPRESENTATIONS AND WARRANTIES OF THE BUYER..............................24
   SECTION 9 REMEDIES.................................................................25
   SECTION 10 INDEMNIFICATION.........................................................28
   SECTION 11 LIMITATION OF LIABILITIES...............................................36
   SECTION 12 SURVIVAL OF CLAIMS AND REMEDIES.........................................37
   SECTION 13.........................................................................38
   SECTION 14 COVENANT NOT TO COMPETE.................................................38
   SECTION 15 FURTHER COVENANTS OF THE BUYER..........................................38
   SECTION 16 CARTEL CLEARANCE, OTHER COVENANTS OF THE PARTIES........................39
   SECTION 17 GENERAL PROVISIONS......................................................39
</TABLE>





<PAGE>   4


                                                                             4
                                   PREAMBLE


WHEREAS, the Seller is a fully owned subsidiary of Celanese AG ("CELANESE");


WHEREAS, the Seller holds all shares in Vintron GmbH ("VINTRON"), a company
engaged in the chlorine chemicals business at the facilities in Knapsack
relating to the research, development, production, packaging, marketing and
sale of


      -     Chlorine


      -     Caustic Soda


      -     Hydrogen


      -     Ethylendichlorid (EDC)


      -     Vinylchlorid (VCM)


      -     Hydrochloric Acid,


such business, to the extent currently conducted, being referred to as the
"BUSINESS";


WHEREAS, Vintron is a company with limited liability, registered with the
commercial register of the local court Bruehl under HRB no. 2740. In the course
of a capital increase in kind (Sachkapitalerhoehung) from a nominal share
capital of DM 50,000 to DM 60,000, the Seller has contributed into Vintron its
chlorine chemicals business at Knapsack, including a share in InfraServ. The
capital increase has been registered in the commercial register as of 20
October 1999.


WHEREAS, the Seller holds the following shares in Vintron:


      a)    one share in the nominal amount of DM 50,000;


      b)    one share in the nominal amount of DM 10,000.


The shares referred to under a) and b) above are hereinafter collectively
referred to as the "SHARES".


WHEREAS, all production activities related to the chlorine chemicals business
as described in the second paragraph of this Preamble are located at the
facilities at Chemiepark Knapsack and the Rhine Harbour Godorf.


WHEREAS, the Seller intends to sell its shares in Vintron and, thus, to divest
the Business;



<PAGE>   5

                                                                             5

WHEREAS, the Buyer, a limited partnership which has been duly established
under the laws of Germany and reported for registration in the commercial
register on 18 May 2000, but has not yet been registered, duly represented by
its general partner CM 00 Vermoegensverwaltung 058 GmbH, registered in the
commercial register of the local court in Munich under HRB 130662 (hereinafter
referred to as CM 058 GmbH), desires to acquire the Seller's shares in
Vintron;


WHEREAS, the Buyer, at the date hereof, has further entered into an agreement
regarding the acquisition of all the shares in Vinnolit Monomer GmbH & Co KG
and in Vinnolit Monomer Geschaeftsfuehrungs GmbH from Vinnolit Kunststoff GmbH,
a joint venture of Wacker Chemie GmbH ("WACKER") and Celanese (through its
wholly owned subsidiary Diogenes Dreizehnte Vermoegensverwaltungs GmbH, to be
renamed Celanese Holding GmbH), in a separate transaction (the "VINNOLIT
TRANSACTION") which shall be consummated simultaneously;


WHEREAS, the Parties agree that the terms of the Agreement and its Schedules
shall comprehensively and conclusively constitute the entire agreement of the
parties in respect of the transactions contemplated by the Agreement.


NOW, THEREFORE, in consideration of the premises and the mutual agreements and
covenants hereinafter set forth, it is hereby agreed as follows:


                                  SECTION 1
                                 DEFINITIONS


For the purpose of the Agreement the terms below shall have the following
meanings:


<TABLE>
<S>                                          <C>
"ADDITIONAL PAYMENT I"                          The Payment to be made by the
                                                Seller into the equity of
                                                Vintron pursuant to Section
                                                2.4 b).

"ADDITIONAL PAYMENT II"                         The payment to be made by the
                                                Seller into the equity of
                                                Vintron pursuant to Section
                                                2.4 c).
</TABLE>



<PAGE>   6
                                                                             6
<TABLE>
<S>                                          <C>
"AGREED ACCOUNTING PRINCIPLES"                  The accounting principles
                                                applicable for the Annual
                                                Accounts as agreed between the
                                                Parties and set forth in
                                                Schedule 6.2 in order to
                                                determine the EBITDA for the
                                                time periods ending on 31
                                                December 2000 and 31 December
                                                2001 as referred to in Section
                                                6.2.

"AGREEMENT"                                     This Sale and Assignment
                                                Agreement together
                                                with all Schedules hereto.

"ANNUAL ACCOUNTS"                               The annual accounts of Vintron
                                                for the business years ending
                                                on 31 December 2000 and 31
                                                December 2001 to be prepared
                                                and audited pursuant to
                                                Section 6.2 (a) hereto.

"AUDITED ANNUAL ACCOUNTS"                       The Annual Accounts as audited
                                                pursuant to Section 6.2 (b)
                                                hereto.

"BUSINESS"                                      The business activities of
                                                Vintron as defined in the
                                                second paragraph of the
                                                preamble to the extent
                                                currently conducted.

"BUYER'S AFFILIATES"                            Enterprises affiliated with
                                                the Buyer within the meaning
                                                of Section 15 German Stock
                                                Corporation Code
                                                ["Aktiengesetz"].

"CLOSING"                                       The consummation of the
                                                transactions contemplated in
                                                the Agreement.

"CLOSING DATE"                                  The date on which the Closing
                                                occurs, as defined in Section
                                                2.4.
</TABLE>



<PAGE>   7
                                                                         7




<TABLE>
<S>                                       <C>
"EBITDA"                                     The financial figure with all
                                             depreciation and amortisation
                                             added back to the operating
                                             profit = earnings from
                                             operations
                                             ["Betriebsergebnis"] according
                                             to German GAAP consistently
                                             applied and based on the
                                             principles of balance sheet
                                             continuity and continuity of
                                             valuation in accordance with
                                             the Agreed Accounting
                                             Principles. For the avoidance
                                             of doubt, it is assumed that
                                             no management cost for the
                                             acquisition of Vintron or
                                             administration of the funds
                                             will be charged and that no
                                             business will be transferred
                                             to other entities and that
                                             business will be run with
                                             continuity of arm's length
                                             principles. For the avoidance
                                             of doubt, it is clarified that
                                             the EBITDA is calculated
                                             excluding any interest or tax.

"EFFECTIVE DATE"                             1 January 2000, 00.00 h.

"FINAL ANNUAL ACCOUNTS"                      The finally binding Audited
                                             Annual Accounts as defined in
                                             Section 6.2 (c).

"FINANCIAL STATEMENTS"                       The financial statements as
                                             defined in Section 6.1.

"GAAP"                                       German generally accepted
                                             accounting principles
                                             ["Grundsaetze ordnungsgemaesser
                                             Buchfuehrung- und Bilanzierung"].

"INFRASERV"                                  InfraServ GmbH & Co. Knapsack
                                             KG having its registered seat
                                             in Bruehl and registered in the
                                             Commercial Register at the
                                             Local Court (Amtsgericht)
                                             Bruehl under HRA 0995, an
                                             entity in which Vintron holds
                                             a minority interest as further
                                             defined in Section 4.1 hereof.
</TABLE>

<PAGE>   8
                                                                             8

<TABLE>
<S>                                          <C>
"REAL PROPERTIES"                               The essential land and
                                                premises leased ["gemietet
                                                oder gepachtet"] by Vintron or
                                                in respect of which Vintron
                                                has hereditary building rights
                                                ["Erbbaurechte"] as defined in
                                                Section 7.17.

"SELLER'S AFFILIATES"                           Enterprises affiliated with
                                                the Seller within the meaning
                                                of Section 15 of the German
                                                Stock Corporation Code
                                                ["Aktiengesetz"]

"SHARES"                                        The shares in Vintron held by
                                                the Seller as described in the
                                                fourth paragraph of the
                                                preamble.

"VESTOLIT"                                      Vestolit GmbH & Co. KG with
                                                its seat in Marl.

"VINNOLIT TRANSACTION"                          The Acquisition of all the
                                                shares in Vinnolit Monomer
                                                GmbH & Co. KG and Vinnolit
                                                Monomer Geschaeftsfuehrungs GmbH
                                                from Vinnolit Kunststoff GmbH
                                                by the Buyer in a separate
                                                transaction as described in
                                                the eighth paragraph of the
                                                preamble.

"VINTRON"                                       Vintron GmbH, a company with
                                                limited liability, registered
                                                with the commercial register
                                                of the local court of Bruehl
                                                under HRB 2740.

</TABLE>

                                  SECTION 2
              SALE AND TRANSFER; EFFECTIVE DATE AND CLOSING DATE


2.1   The Seller hereby sells the Shares to the Buyer. The Buyer hereby
      accepts the sale. The sale shall have economic effect as of the
      Effective Date (as defined in Section 2.3).


2.2   The Seller hereby transfers the Shares to the Buyer. Buyer hereby
      accepts such transfer. The transfer shall take effect from the Closing
      Date (as defined in Section





<PAGE>   9
                                                                             9





      2.4). Prior to the Closing Date, Vintron shall execute an
      indemnification letter in which Vintron undertakes vis-a-vis the Seller
      to be fully responsible for all liabilities caused by the conduct of the
      business operation of Vintron after the Closing Date and to indemnify
      Seller and hold the Seller harmless, from all such liabilities.


2.3   Throughout this Agreement, "EFFECTIVE DATE" shall be 1 January 2000,
      00.00 h.


2.4.  Throughout this Agreement, "Closing Date" take place at the offices of
      Hengeler Mueller Weitzel Wirtz, Frankfurt am Main, or at such other
      place as Seller and Buyer mutually agree, as soon as practicable, and,
      unless otherwise agreed or waived by the Seller and the Buyer, under no
      circumstances no later than (5) five business days after all of the
      Closing Conditions (as defined in Section 3) have been satisfied:


      a)    Seller shall pay the Consideration (as defined in Section 5.1);


      b)    Seller and Vintron shall execute a loan agreement, providing for a
            DM 76 million interest free loan to Vintron to be repaid on 31
            December 2007. The loan agreement shall provide that the loan
            ranks ahead of shareholder loans, if any, granted to Vintron, and
            behind any bank financing or supplier financing regarding "PROJECT
            ZEUS" as described in SCHEDULE 2.4 b). The loan agreement shall
            further provide that the loan becomes payable on 31 December 2007
            at the latest.


2.5   Immediately prior to the performance of the acts described in Section
      2.4,


      a)    Seller shall pay an amount of DM 100 million (Deutsche Mark one
            hundred million) as additional payment into the equity (Section
            272(2) No. 4 German Commercial Code) of Vintron (the "ADDITIONAL
            PAYMENT I");


      b)    Seller shall pay an amount of DM 37 million (Deutsche Mark
            thirty-seven million) as additional payment into the equity
            (Section 272(2) No. 4 German Commercial Code) of Vintron (the
            "ADDITIONAL PAYMENT II");


      c)    the profit and loss absorption agreement of December 21, 1998
            entered into between Seller and Vintron shall be discontinued with
            effect as of the Closing Date, it being understood that, at the
            Seller's option, the fiscal year may be changed for this purpose.


2.6   The Parties shall confirm that all Closing Conditions have either been
      satisfied or waived and all actions to be taken on the Closing Date have
      been taken or waived.




<PAGE>   10

                                                                             10



                                  SECTION 3
                              CLOSING CONDITIONS


3.1   This Agreement shall be closed only if the following conditions have
      been either satisfied or waived as agreed between Seller and Buyer which
      consent by either Party shall not be unreasonably withheld:


      a)    The execution of the VC-Liefervertrag between Vintron and Vinnolit
            Monomer GmbH & Co. KG ("Vinnolit") in the form initialled between
            Vintron and Vinnolit as of 16 December 1998 pursuant to which
            Vintron undertakes to supply VCM and EDC to Vinnolit at the sites
            of Knapsack and Koeln-Merkenich.


      b)    The execution of the VCM expansion contract between Vintron and
            Krupp Uhde in the form initialled between Vintron and Krupp Uhde
            pursuant to which Krupp Uhde undertakes to plan, provide, supply
            and set up, ready for immediate occupation and manufacturing, a
            330,000 jato VCM facility, it being understood that Section 9.3 of
            the VCM expansion contract might still be subject to negotiations.


      c)    The execution of an ethylene contract between Vintron and Celanese
            AG & Co. Procurement Olefin KG providing for an amount of appr.
            150,000 t/a up to the year 2007 and on the transfer of the
            property in the ethylene pipelines L1 and L8 (consisting of L8.1,
            L8a, and L8b), for the avoidance of doubt, the section outside the
            plants as well as the section inside the plants Huerth and
            Knapsack, from Vintron to InfraServ GmbH & Co Hoechet KG at
            book-value.


      d)    Advent has obtained the final and definitive commitment by the
            banks to provide the financing required for the transactions
            contemplated by this Agreement.


      e)    The Parties shall have obtained the unconditional approval,
            clearance, or notice of none-action from the German Federal Cartel
            Office and/or the European Commission under pertinent merger
            control provisions in respect of the consummation of the
            transactions contemplated by this Agreement.


      f)    The Parties shall have reached an agreement about the use of the
            VC pipeline at the Godorf port, either by providing for a transfer
            of title in the VC pipeline





<PAGE>   11

                                                                             11



            to Vintron or by granting long-term access to Vintron on terms
            which are fair and reasonable.


      g)    Celanese AG shall have entered into option and voting agreements
            (the "OPTION AND VOTING AGREEMENTS") (i) with Vintron regarding
            the shareholding of Celanese AG as limited partner of InfraServ
            GmbH & Co. Knapsack KG and (ii) with Vinnolit Monomer GmbH & Co.
            KG regarding the shareholding of Celanese AG as limited partner of
            InfraServ GmbH & Co. Gendorf KG, which Option and Voting
            Agreements shall provide substantially as follows:


            (i)   Celanese AG irrevocably grants (i) to Vintron the option to
                  acquire from Celanese AG a 5.1% interest as limited partner
                  ("Kommanditist") in InfraServ GmbH & Co. Knapsack KG and
                  (ii) to Vinnolit Monomer GmbH & Co. KG the option to acquire
                  from Celanese AG a 9.1 % interest as limited partner in
                  InfraServ GmbH & Co. Gendorf KG (collectively, the "KG
                  SHAREHOLDING") against payment of a purchase price amounting
                  to the book value of the AG Shareholding in the books of
                  Celanese AG as per 31 December 1999.


                  The transfer of the KG Shareholding shall be subject to the
                  approval of the partner's meeting with a majority of 80% of
                  the votes cast as provided for in the respective partnership
                  agreement ("Gesellschaftsvertrag") of the InfraServ
                  partnership and further subject to the registration of the
                  acquiror as successor by way of singular succession
                  ["Einzelrechtsnachfolge"] in the respective commercial
                  register.


                  The KG Shareholding shall not carry any potential obligation
                  to pay additional cash contributions
                  ("Nachschussverpflichtung") within the meaning of the
                  respective partnership agreement.


                  The purchase agreement shall contain the representations by
                  Celanese AG (i) that all contributions to the KG
                  Shareholding have been fully paid in and that no repayments
                  of capital contributions has been effected, neither directly
                  nor concealed, (ii) that the KG Shareholding is validly
                  existing, free and clear of any liens, rights, claims and
                  privileges of third parties and (iii) that Celanese AG may
                  freely dispose such KG





<PAGE>   12

                                                                             12





                  Shareholding, unless otherwise set forth in the respective
                  partnership agreement. No further representations,
                  warranties or guarantees shall be given by Celanese.


            (ii)  For as long as Vintron or Vinnolit Monomer GmbH & Co. KG, as
                  the case may be, does not hold more than 20 % of the voting
                  rights in the respective InfraServ partnership, Celanese
                  hereby undertakes to exercise its voting rights in partners'
                  meetings of the respective InfraServ partnership only upon
                  instruction of Vintron or Vinnolit Monomer GmbH & Co. KG, as
                  the case may be, to the extent required to avoid that
                  resolutions be adopted with a majority of 80 % of the votes
                  cast against the instructions by Vintron or Vinnolit Monomer
                  GmbH & Co. KG. Prior to such partners' meetings, Vintron or
                  Vinnolit Monomer KG, as the case may be, shall give written
                  instructions to Celanese AG specifying the reasons for the
                  desired voting.


                  Notwithstanding the generality of the foregoing, Celanese AG
                  shall use reasonable efforts to procure that the hereditary
                  building right held by Vintron at the site of Knapsack and
                  by Vinnolit Kunststoff GmbH/Vinnolit Monomer GmbH & Co. KG
                  at the site Gendorf shall be extended after expiration, and
                  that the respective partners' meetings approve the transfer
                  of the KG Shareholding to Vintron and Vinnolit Monomer GmbH
                  & Co. KG.


      h)    The closing conditions of the Vinnolit Transaction have been
            satisfied or waived (not taking into regard a closing condition
            according to which the Vinnolit Transaction shall be closed only
            if the closing condition of this Section 3.1 h) has been satisfied
            or waived).


3.2   Buyer and Seller undertake to use best reasonable endeavours to ensure
      that the closing conditions set forth in section 3.1 above are satisfied
      as soon as possible after the date hereof.


                                  SECTION 4
             INFRASERV AND OTHER CONTRACTS CONNECTED TO CELANESE


4.1   The chlorine chemicals business of Vintron is an integrated part of the
      facilities at Knapsack which is hosting, and is used by, several
      companies and has been, and





<PAGE>   13

                                                                             13





      continues to be, developed into an industrial park under the management
      of InfraServ, a limited partnership established under German law. In
      order to allow for an effective and user-oriented management of the
      site, the title in the land and buildings at Knapsack was transferred
      from Hoechst to InfraServ. Vintron is a limited partner ("Kommanditist")
      of InfraServ holding a limited partnership interest in an amount equal
      to 15% of the fixed capital (Hafteinlagen und Pflichteinlagen) of
      InfraServ as stated in the fixed capital accounts of InfraServ (it being
      understood that this partnership interest, under the rules of Section 6
      of the partnership agreement ("Gesellschaftsvertrag"), obliges the
      partner to pay 21.75% of the additional cash contributions
      ("Nachschuesse"), if any, as provided for in the contribution agreement
      between the Seller and Vintron dated December 21, 1998 as amended August
      27, 1999.


      For the avoidance of doubt, the Buyer hereby acknowledges the existence
      of contractual relationships between Vintron and InfraServ.


4.2   Seller and Vintron will discontinue the profit and loss agreement of
      December 21, 1998 entered into between Seller and Vintron as of the
      Closing Date. To the extent necessary, Buyer will, also after the
      Closing Date, cause Vintron to take all actions and cause to be issued
      all declarations which might still be necessary or appropriate for the
      due discontinuation of the profit and loss agreement and the publication
      and registration of the discontinuation with the competent authorities.


      The Parties acknowledge that the consideration has been calculated and
      the financial arrangements for the acquisition of Vintron have been made
      on the assumption that actual losses for the fiscal year 2000 would not
      be compensated by the Seller due to the profit and loss agreement. Any
      profits passed on to the Seller for the period until the Closing Date
      under the profit and loss agreement shall not be reclaimed or requested
      by Buyer; Section 5.3 shall remain unaffected.


4.3   The Buyer shall procure that Vintron will pay back in full the financial
      interest bearing liabilities, not including any trade receivables, owed
      by Vintron to the Seller and/or the Seller's Affiliates as per the
      Closing Date, if any, within 5 (five) business days, regardless whether
      due or not. On the other side, the Seller shall, and shall procure that
      the Seller's Affiliates will, pay back the financial interest bearing
      liabilities, not including any trade receivables, owed by them to
      Vintron as per the Closing Date, if any, within (5) five business days,
      regardless of whether due or not.




<PAGE>   14
                                                                             14



                                  SECTION 5
                                CONSIDERATION


5.1   The consideration for the Shares shall be negative and amount to DM
      20,861,741.50 (Deutsche Mark twenty million eight hundred sixty one
      thousand seven hundred forty one and 50/100) to be paid by Seller to
      Buyer on the Closing Date (the "PURCHASE PRICE"). The amount of the
      Purchase Price reflects the net interest bearing financial debts of
      Vintron as of 31 December 1999 (plus DM 1.00) and shall be used to
      satisfy interest bearing financial debts of the Seller.


5.2   The Additional Payment I shall be lost and forfeited provided that the
      Buyer fully complies with its obligations under Section 5.4.


5.3   Buyer shall cause Vintron to pay back the Additional Payment II minus
      the amounts paid by Vintron to the Seller pursuant to the Profit and
      Loss Agreement dated 21 December 1998 for the time period between 1
      January 2000 and the Closing Date in the amount by which the accumulated
      EBITDA as shown in the Final Annual Accounts of Vintron as of 31
      December 2000 and as of December 31, 2001 exceeds in the positive the
      amount of DM - 48,700,000.00 (Deutsche Mark minus forty eight million
      seven hundred thousand) (e.g., if the accumulated EBITDA amounts to DM -
      45,000,000 then the amount to be paid back shall be DM 3,700,000). The
      redemption claim shall become due one week after the Final Annual
      Accounts of Vintron as of December 31, 2001 have been established. For
      the avoidance of doubt, the calculated accumulated EBITDA of DM -
      48,700,000 (Deutsche Mark minus forty eight million seven hundred
      thousand) includes the DM - 20,400,000 (Deutsche Mark minus twenty
      million four hundred thousand) referred to in Section 10.3.


      The Buyer shall cause Vintron to use all reasonable endeavours to ensure
      that the EBITDA will exceed the amount referred to above. The Buyer
      shall from time to time and/or on written request of the Seller, keep
      informed the Seller in writing on Vintron's endeavours and measures
      taken in this respect. The Buyer shall cause Vintron to promptly submit
      to the Seller (i) copies of any reports and other information relating
      to the financial or economic situation of the Buyer and/or Vintron as
      delivered to the banks of the Buyer or Vintron from time to time, (ii)
      the audited consolidated and individual annual statements of the Buyer
      and Vintron and (iii) monthly management reports, substantially in the
      form as prepared by the management and delivered to Celanese as at the
      date hereof. On request of the Seller, twice a year, the Buyer shall
      grant and procure that Vintron grants, to the Seller or


<PAGE>   15

                                                                             15





      the Seller's accountants, access to its books and records or other
      relevant documents for inspection or copying regardless of whether those
      documents are situated at their properties or elsewhere.


5.4   Provided that Krupp Uhde has complied with its obligations under the VCM
      expansion contract referred to in Section 3.1 b), Buyer will cause
      Vintron to complete all planned expansion of Vintron's production and
      transport capacity at Knapsack known as Project Zeus as defined in
      SCHEDULE 2.4 B)(the "Expansion Obligation"). Buyer shall be deemed to
      have fully complied with the Expansion Obligation upon complete and
      unconditional fulfilment of its payment obligations under the VCM
      expansion contract. Furthermore, Buyer will cause Vintron to use the
      Additional Payment I for the Expansion Obligation only and that it will
      cause Vintron not to make any payments to the Buyer or any company
      affiliated with Buyer by way of release of capital reserves, decrease of
      share capital, extraordinary dividends (including hidden dividends),
      granting of intra-company loans or guarantees or any form of payment for
      which no appropriate consideration is paid.


      In the event that (i) prior to the compliance with the Expansion
      Obligation Buyer or any company affiliated with Buyer violates any of
      the aforementioned obligations, and (ii) Vintron does not comply with
      its payment or other obligations under the VCM expansion contract, then
      Buyer shall pay, and Buyer shall procure that Vintron shall pay, as
      joint debtors (Gesamtschuldner), an amount equal to the Additional
      Payments I and II which has been used contrary to the obligations set
      forth in this Section 5.4 as lump-sum damages compensation, it being
      understood that the right of Seller to claim additional damages suffered
      shall remain unaffected therefrom.


      In order to avoid any double recovery, a violation of the aforementioned
      obligations shall not result in payment obligations under this Section
      5.4 to the extent that the violation results in payment obligations
      under 5.3.


      Buyer is aware that Seller, with the approval of Buyer, has made and
      will make prepayments to Krupp Uhde for the implementation of Project
      Zeus.


                                  SECTION 6
                               ANNUAL ACCOUNTS


6.1   FINANCIAL STATEMENTS. The Seller has delivered to the Buyer complete and
      accurate copies of the audited financial statements of Vintron for the
      business year ended 31



<PAGE>   16

                                                                             16





      December 1999 (the "FINANCIAL STATEMENTS"). The Financial Statements
      have been prepared in accordance with German generally accepted
      accounting principles ("GAAP") consistently applied and based on the
      principles of balance sheet continuity ["unter Wahrung der
      Bilanzierungs- und Bewertungskontinuitaet"].


6.2   ANNUAL ACCOUNTS 2000 AND 2001. With regard to the determination of the
      EBITDA for the business years 2000 and 2001 the following shall apply:


      (a)   The Buyer shall cause Vintron to prepare, without undue delay
            after the respective record date, its annual accounts as of 31
            December 2000 and 31 December 2001 in accordance with GAAP (the
            "ANNUAL ACCOUNTS"). In order to determine the EBITDA for the
            respective business years, the Annual Accounts shall be adjusted,
            in a separate calculation, in accordance with the agreed
            accounting principles as defined in SCHEDULE 6.2 hereto (the
            "AGREED ACCOUNTING PRINCIPLES").


      (b)   The Buyer shall cause the auditor of Vintron (i) to audit without
            undue delay, but not later than (3) three months after the
            respective balance sheet date, the Annual Accounts, (ii) to adjust
            them, in a separate calculation, within such time period to comply
            with the Agreed Accounting Principles (the Annual Accounts so
            audited and, if applicable, adjusted the "AUDITED ANNUAL
            ACCOUNTS") and (iii) to make available without undue delay an
            authentic copy of the Audited Annual Accounts to the Seller.


      (c)   Within (1) one month after receipt of the Audited Annual Accounts
            for the respective years, the Seller is entitled to raise
            objections in writing that and in what respect the Audited Annual
            Accounts, to the extent relevant for the determination of the
            EBITDA, do not comply with the Agreed Accounting Principles. Any
            disputes between the Seller and the Buyer which cannot be settled
            directly between them shall be settled, upon request of either
            Party, by an independent auditor ("INDEPENDENT AUDITOR") acting as
            expert arbitrator ["Schiedsgutachter"]. If the Buyer and the
            Seller cannot mutually agree upon such expert arbitrator within
            (2) two weeks after either Party has requested its appointment,
            the expert arbitrator shall be appointed by the Institute of
            Chartered Accountants ["Institut der Wirtschaftspruefer e.V."] in
            Duesseldorf. To the extent permissible by law (Section 319 of the
            German Civil Code) the findings of such expert arbitrator shall be
            finally binding on the Parties; the Buyer and the Seller shall
            equally bear the costs of such expert arbitrator. If no objections
            will





<PAGE>   17
                                                                             17




            be raised pursuant to the first sentence of this sub-section (c)
            the Audited Annual Accounts are the "FINAL ANNUAL ACCOUNTS" within
            the meaning of this Agreement. If objections will be raised
            pursuant to sentence 1 of this sub-section, the Audited Annual
            Accounts as adjusted pursuant to the settlement between the
            Parties or pursuant to the findings of the expert arbitrators are
            the "Final Annual Accounts" within the meaning of this Agreement.


      (d)   The Buyer shall procure, and cause Vintron to procure, that the
            audited EBITDA of Vintron can be identified separately, e.g. by
            maintaining the book-keeping system ["Buchungskreise"] as
            currently used by the Companies.


      (e)   The Buyer shall request the management of Vintron to ensure that,
            on a timely basis, the Seller, any accounting firm appointed for
            these purposes by the Seller and the expert arbitrator receive all
            necessary assistance and a granted access to all relevant
            documents in order to audit and examine the Annual Accounts, to
            the same extent as if they were auditing annual accounts.


                                  SECTION 7
                 REPRESENTATIONS AND WARRANTIES OF THE SELLER


The Seller hereby represents and warrants to the Buyer by way of independent
guarantee ("Selbstaendiges Garantieversprechen") as of the date hereof and,
unless otherwise provided hereunder, as of the Closing Date, with the legal
consequences as conclusively set forth in Section 9, and subject to the terms
and conditions set forth in Section 9 and 11, as follows:


7.1   INCORPORATION AND VALID EXISTENCE OF THE SELLER. The Seller is a limited
      liability company ["GmbH"] duly established and validly existing under
      the laws of Germany and has all necessary corporate power to execute and
      deliver this Agreement and to perform fully its respective obligations
      hereunder and to consummate the transactions contemplated hereby.


7.2   INCORPORATION AND VALID EXISTENCE OF VINTRON. Vintron is an enterprise
      duly established and validly existing under the laws of Germany.


7.3   OWNERSHIP OF SHARES. The statements contained in the Preamble and
      Section 4 are correct. All contributions to the registered share capital
      of Vintron and to the interest in InfraServ have been fully paid in. No
      repayment of capital contributions has been effected, neither directly
      nor concealed.




<PAGE>   18
                                                                             18




7.4   EXISTENCE OF SHARES, THIRD PARTY RIGHTS. The Shares and the shares held
      by Vintron in IntraServ are validly existing, free and clear of any
      liens, rights, claims and privileges of third parties and the Seller may
      freely and without any restrictions dispose such shares, unless
      otherwise set forth in Section 2.1 or reflected in the corporate
      documents referred to in Section 7.5 below. No options, pre-emptive
      rights or similar undertakings have been given in respect of such shares
      and no shareholders agreement or any similar undertaking regarding such
      shares has been entered into unless otherwise reflected in the corporate
      documents referred to in Section 7.5 below.


7.5   CORPORATE STATUS OF VINTRON. The corporate documents as registered with
      and deposited at the relevant Commercial Registers and, in respect of
      InfraServe, which have been provided to Buyer are correct and duly
      reflect the corporate status of Vintron and InfraServ; no resolutions of
      the shareholder of Vintron which are required to be registered in the
      commercial register or similar registers have been passed which have not
      been registered.


7.6   CORPORATE AGREEMENTS. There are no corporate agreements in the sense of
      Sections 291,292 German Stock Corporation Act nor other cooperation or
      joint venture agreements, nor fiscal unity, domination or profit pooling
      agreements which bind Vintron.


7.7   PROFIT PARTICIPATION AGREEMENTS, SILENT PARTNERSHIPS. There are no
      agreements regarding participation in the profit of Vintron of any kind,
      in particular there are no silent partnerships, or loans with profit
      participation ["partiarische Darlehen"].


7.8   FINANCIAL STATEMENTS. The Statements made under Section 6.1 are true and
      correct.


7.9   NET INTEREST BEARING FINANCIAL DEBTS. The net interest bearing financial
      debts of Vintron (i.e. interest bearing financial debts minus cash of
      Vintron as of the Closing Date) shall not exceed the amount of DM
      35,000,000 (Deutsche Mark thirty five million) minus debts incurred up
      until the Closing Date for Project Zeus and related expansion projects
      (together the "EXPANSION PROJECTS"), it being understood that the Seller
      may cause Vintron to take all measures within the scope defined in
      Sections 7.20 and 7.21 which do not exceed the aforementioned amount.


7.10  ASSETS. Vintron




<PAGE>   19

                                                                             19





      (i)   is the sole and unrestricted owner or lessee of the assets, which
            were reflected in the Financial Statements of Vintron, with the
            exception of assets which were sold, disposed of (including the
            ethylene pipeline), replaced or, in the case of receivables,
            collected since the date of the Financial Statements, and
            including those acquired in the ordinary course of business after
            the date thereof, and


      (ii)  the owned assets are unencumbered by third parties' rights, with
            the exception of lessor's liens, liens or similar rights under
            general business terms of banks and suppliers' liens under general
            sales agreements, e.g. customary reservation of title rights
            ["Eigentumsvorbehalte"], and


      (iii) Vintron owns or leases all assets ("Anlagevermoegen") and
            inventories ("Umlaufvermoegen") necessary for carrying out the
            Business and, to the Best Knowledge, all such assets and
            inventories are in a condition which is adequate to carry on the
            Business in the ordinary course of business and in substantially
            the same fashion and manner as prior to the Closing Date, except
            for ordinary tear and wear and unless liability reserves were
            accrued;


      (iv)  to the Best Knowledge, the ordinary and extraordinary repair
            budgets provide for adequate reserves regarding Vintron's
            equipment;


      (v)   the buildings on the Real Properties are in good repair and
            condition.


7.11  BANKRUPTCY. No insolvency proceedings have been initiated against
      Vintron nor are there, to the Best Knowledge, any circumstances which
      would justify the initiation of such proceedings. No circumstances exist
      pursuant to applicable Insolvency Codes or the Voidancy Act
      ["Anfechtungsgesetz"] which would justify the voidance of this
      Agreement.


7.12  LABOUR MATTERS. To the Best Knowledge, as at the date hereof, there are
      no specific union activities involving Vintron, and there is no pending
      or, threatened strike, picketing, work stoppage, work slowdown or other
      similar labour trouble.


7.13  EMPLOYEES. To the Best Knowledge,


      (i)   all obligations, whether arising by operation of law, by agreement
            or past custom, for payments and contributions with respect to
            direct or indirect pension and retirement benefits or other
            compensational benefits, such as anniversary payments to the
            employees of Vintron, for periods prior to the date


<PAGE>   20

                                                                             20





            hereof have been paid by Vintron or adequately accrued for in the
            Financial Statements in accordance with Section 6a German Income
            Tax Act ["EStG"] and the Seller will procure that Vintron pays or
            accrues for such obligations until the Closing Date;


      (ii)  Vintron as at the date hereof does not employ or retain more than
            270 employees (not taking into account employment relationships
            which are limited in time or suspended);


      (iii) as at the date hereof none of the key-employees (Dr. Hermann
            Berwe, Dr. Michael Winhold, Hermann-Peter Mueller) have terminated
            their current employment or have threatened to terminate such
            employment. It is, however, known that Hermann-Peter Mueller will
            regularly retire in 2000.


      (iv)  There are no material informal and/or unwritten undertakings to
            employees.


7.14  MATERIAL CONTRACTS. For the purpose of this Section 7.14 all agreements
      which are material to the Business are hereinafter referred to as the
      "MATERIAL CONTRACTS". To the Best Knowledge, there are no Material
      Contracts other than the contracts presented to the Buyer in the course
      of the Due Diligence referred to in Section 9.2. The Material Contracts
      are in full force and effect and, to the Best Knowledge, are enforceable
      against the Parties thereto in accordance with their terms. To the Best
      Knowledge, no circumstances exist that will give any party to the
      Material Contracts the right to terminate, other than ordinary
      termination rights, in particular not as a result of the transactions
      contemplated under this Agreement. Vintron has not received any written
      information regarding any action or any material violation of any
      Material Contracts. For the avoidance of doubt, it is clarified that
      this Section 7.14 shall not apply to loan agreements of Vintron, in
      particular regarding working capital facilities.


7.15  INSURANCE. With regard to insurance policies


      (a)   to the Best Knowledge, each of Vintron's Assets of insurable
            nature, to the extent material to the Business, is covered by
            insurance policies (the "INSURANCE POLICIES") with insurance
            companies of good reputation duly authorised to carry on insurance
            business against fire, accident and all other risks ordinarily
            insured against as is customary in industry;


<PAGE>   21

                                                                             21





      (b)   to the Best Knowledge, Vintron has satisfied in full all of its
            material obligations under the Insurance Policies, and is not in
            material default under any of them nor does any condition exist
            with respect to any of the Insurance Policies that, with notice or
            lapse of time or both, would constitute any of such default of
            Vintron thereunder;


      (c)   there are no claims made by Vintron or any person on its behalf
            under the Insurance Policies, exceeding individually or in the
            aggregate DM 50,000 (Deutsche Mark fifty thousand), which are
            outstanding. To the Best Knowledge, no event has arisen which
            might give rise to any material claim under any of the Insurance
            Policies.


7.16  INTELLECTUAL PROPERTY RIGHTS. With regard to intellectual property
      rights the Seller represents and warrants in the form of an independent
      guarantee that


      (a)   Vintron is the exclusive owner or licensee of the intellectual
            property rights until expiration of the licensed rights listed in
            SCHEDULE 7.16 as may be amended by Seller within five business
            days from the date hereof (the "INTELLECTUAL PROPERTY RIGHTS");


      (b)   to the Best Knowledge, Vintron does not require any intellectual
            property rights other than the Intellectual Property Rights in
            order to conduct the Business as currently conducted;


      (c)   to the Best Knowledge, neither the operation of the Business nor
            its products infringe any patents or other intellectual property
            rights of any third party;


      (d)   no claim has been brought against Vintron alleging an infringement
            of intellectual property rights as at the date hereof and to the
            Best Knowledge no third party has threatened to bring any action
            regarding any such alleged infringement.


7.17  REAL PROPERTIES. The real properties as set forth under SCHEDULE 7.17
      (the "REAL PROPERTIES") constitute the essential land and premises
      leased ["gemietet oder gepachtet"] by Vintron or in respect of which
      Vintron has hereditary building rights ["Erbbaurechte"]. Vintron leases
      no land or premises with annual leases of more than DM 250,000 (Deutsche
      Mark two hundred fifty thousand) other than the Real Properties. Vintron
      does not own any real properties.



<PAGE>   22

                                                                             22


7.18  LITIGATION. Vintron is not party, neither as claimant nor defendant, to
      any litigation, including arbitration proceedings, for the avoidance of
      doubt also with regard to product liability claims, of which the amount
      in dispute exceeds DM 250,000 (Deutsche Mark two hundred fifty
      thousand). To the Best Knowledge, there are no governmental
      investigations or enquiries or administrative proceedings initiated or
      pending against Vintron in which the amount involved exceeds DM 250,000
      (Deutsche Mark two hundred fifty thousand), and, to the Best Knowledge,
      there are no such litigation, investigations, enquiries or
      administrative proceedings threatened against Vintron.


7.19  COMPLIANCE WITH LAWS. Vintron is to the Best Knowledge not in violation
      of any published law ["Gesetz im materiellen Sinne"], ordinance
      ["Verfuegung"], regulation ["Verordnung"], or any other requirement of
      any court or arbitrator, being material for the Business.


7.20  CONDUCT IN THE ORDINARY COURSE. Since 1 January 2000 until the date
      hereof,


      (a)   the Business of Vintron has been conducted in the ordinary course
            and shall continue to be conducted in the ordinary course until
            the Closing as a going concern, it being understood that all
            actions taken by Vintron for the implementation of the Expansion
            Projects shall be deemed to be in the ordinary course of business.


      (b)   Vintron has not declared any dividends in respect of the Shares
            and no such Dividends shall be declared until the Closing, except,
            for the avoidance of doubt, payments to be made under the loss and
            profit agreement as of 21 December 1998.


7.21  ABSENCE OF MATERIAL ADVERSE CHANGES. Since 1 January 2000 until the date
      hereof,


      (i)   the remunerations payable to the managing directors, officers,
            employees, agents or consultants have not been increased outside
            the ordinary course of business;


      (ii)  Vintron has not incurred any material liabilities or entered into
            any other material transactions outside the ordinary business,
            except for investments connected with the Expansion Projects as
            defined in Section 7.9;


<PAGE>   23


                                                                             23


      (iii) there has not been any material loss or damage to, or any material
            interruption in the use of any of Vintron's material assets;


      (iv)  Vintron has not made any capital expenditures [("Ausgaben zur
            Anschaffung von Anlagevermoegen")] which, in the aggregate since 1
            January 2000, exceed DM 5,000,000.00 (Deutsche Mark five million),
            except for expenditures regarding the Expansion Projects.


      (v)   there has not been any material adverse change, either
            individually or in the aggregate, in the Business of Vintron.


      (the events under (i) - (v) hereinafter the "MATERIAL ADVERSE CHANGE").


      From the date hereof through the Closing Date, the Seller shall (A)
      cause Vintron not to enter into arrangements constituting a Material
      Adverse Change within the sense of (i), (ii) or (iv) above without the
      prior consent of the Buyer, and (B) promptly inform the Buyer if any of
      such Material Adverse Changes within the sense of (iii) or (v) above
      occurs from the date hereof through the Closing Date.


      The Seller and the Buyer shall be entitled to rescind this Agreement if
      a Material Adverse Change occurring from the date hereof through the
      Closing Date, without the consent of the Buyer, results in damage or
      liabilities of Vintron exceeding DM 12,500,000 (Deutsche Mark twelve
      million five hundred thousand), unless covered by insurance policies.


7.22  FINDER'S FEES. Vintron has not incurred any liability or brokerage or
      finders' fees or agents' commissions or similar payments in connection
      with this Agreement.


7.23  TRADE RECEIVABLES. As of the Closing Date 90% of accounts receivable
      shall be collectible within (6) six months after the Closing Date
      without deductions, unless customary or agreed by Vintron with the
      respective customer. The Seller and the Buyer agree that in the event
      that the representation and warranty made under this Section 7.23
      results in a claim of the Buyer pursuant to the terms and conditions set
      forth in Section 9, the Buyer shall cause Vintron to assign accounts
      receivables to the extent the Seller is in breach of the representation
      set forth in this Section 7.23 to the Seller. The Buyer shall procure
      that any payments of such receivables to Vintron after the transfer of
      title shall be promptly paid to the Seller. The Buyer shall give,
      without undue delay, immediate notice of the transfer of title to the
      debtors ["Abtretungsanzeige"].



<PAGE>   24

                                                                             24





7.24  LIABILITIES. Vintron has no liabilities obligations within the sense of
      Section 251 HGB ["Haftungsverhaeltnisse"] or any other security
      arrangements (e.g. letters of comfort ["Patronatserklaerungen"]) for
      liabilities of third parties, except as reflected or reserved against in
      the Financial Statements or as stated under the balance sheet of the
      Financial Statements or unless otherwise disclosed in SCHEDULE 7.24.


7.25  BEST OF KNOWLEDGE. If a representation and warranty under this Agreement
      is made to the best of knowledge (the "BEST KNOWLEDGE"), such Best
      Knowledge shall be present if the managing directors of Celanese and
      Celanese Chemicals Europe GmbH and Vintron should have obtained
      knowledge about the underlying facts and circumstances giving rise to a
      breach of the representation or guarantee applying the standard of care
      of a prudent businessman pursuant to Section 43 German Limited Liability
      Companies Act ["GmbHG"], provided, however, such representation and
      warranty shall not imply an obligation of such managing directors and
      key employees to make any special inquiry or investigation merely by
      reason of the transactions contemplated by this Agreement.


                                  SECTION 8
                 REPRESENTATIONS AND WARRANTIES OF THE BUYER


8.1   INCORPORATION, CORPORATE POWER. The Buyer represents and warrants to the
      Seller by way of independent guarantee ["selbstaendiges
      Garantieversprechen"] that, as of the date hereof and as of the Closing
      Date, the Buyer is a limited partnership duly established under the laws
      of Germany, having all requisite corporate power and authority to
      execute, deliver and perform its obligations under the Agreement and to
      consummate the transactions contemplated hereby, and CM 058 GmbH as its
      general partner is a company duly incorporated and registered under the
      laws of Germany as a limited liability company ["GmbH"] in the local
      court in Munich under HRB 130662.


8.2   CORPORATE ACTION. The Buyer represents and warrants to the Seller by way
      of independent guarantee ["selbstaendiges Garantieversprechen"] that the
      Buyer has taken all necessary corporate action and obtained all
      necessary consents to authorise (i) the execution and delivery of the
      Agreement and (ii) the performance of the Agreement and the consummation
      of the transaction contemplated thereby.


8.3   FINANCING AND CARTEL APPROVAL. The Buyer represents and warrants as of
      the date hereof and as of the Closing Date to the Seller by way of
      independent guarantee




<PAGE>   25

                                                                             25




      ["selbstaendiges Garantieversprechen"] that, to its best knowledge, there
      are no existing facts or circumstances which


      (i)   might affect its potential obligation to repay the Additional
            Payment I as set forth in Section 5.4, or the Additional Payment
            II as set forth in Section 5.3 and 5.4, or


      (ii)  on the side of the Buyer and the Buyer's Affiliates are of
            relevance from a cartel law point of view and which might prevent
            clearance by any cartel authorities referred to in Section 16. The
            Seller is aware that the Buyer holds an interest in Vestolit equal
            to approx. 10% of the total share capital of the company.


                                  SECTION 9
                                   REMEDIES


9.1   REINSTATEMENT. Unless otherwise provided in this Agreement, if and to
      the extent that representations and warranties of the Seller are
      incorrect and result in a claim of the Buyer under Section 7, the Seller
      shall


      (a)   put Vintron in a position as if such incorrect representations and
            warranties were true ["Naturalrestitution"] or, at the Seller's
            option,


      (b)   pay the amount in cash to the Buyer or Vintron which corresponds
            to the loss of Vintron in respect of the matter giving rise to the
            claim.


      If the Seller fails to make the incorrect representations and warranties
      true within a period of (2) two months following receipt of written
      notice of such claim pursuant to (a) above, at the Buyer's option, the
      Seller shall effect payment of the amount in cash which corresponds to
      the damage (within the sense of Section 249 Sentence 2 BGB, unless
      otherwise set forth in Section 9.4) of Vintron either to Vintron or to
      the Buyer. Sections 377, 378 HGB shall not apply. In the event of a
      violation of Section 7.9, the Seller shall, in deviation from this
      Section 9.1, be obliged to grant a loan to Vintron equal to the amount
      by which the net interest bearing financial debts have been incurred in
      violation of Section 7.9. The loan shall be repayable without interest
      (5) five business days after the amount of Vintron's net interest
      bearing financial debts meets, or falls short of, the amount described
      in Section 7.9. The Buyer shall cause Vintron to use all reasonable
      efforts to reduce the interest bearing

<PAGE>   26
                                                                             26


      debts minus debts incurred up until the Closing Date for the Expansion
      Projects to or below the amount of DM 30,000,000 (Deutsche Mark thirty
      million) within the ordinary course of business.


9.2   BUYER'S KNOWLEDGE. The Seller shall not be liable to the Buyer for any
      claims brought by the Buyer in respect of any alleged breach of a
      representation or warranty made by the Seller herein, if the Buyer or
      its advisors at the date hereof had knowledge of such breach within the
      sense of Section 460 of the German Civil Code ["BGB"]. The Buyer
      confirms that it and its advisers have thoroughly examined the legal,
      tax and financial information relating to Vintron ("DUE DILIGENCE"). The
      Buyer and/or persons appointed by the Buyer furthermore had the
      opportunity to have detailed discussions with members of the management
      board of the Seller and Vintron. The restrictions pursuant to Section
      460 BGB shall not apply with respect to the representations given in
      Section 7.3 regarding InfraServ.


9.3   NO FURTHER REPRESENTATIONS AND WARRANTIES. The Buyer may only bring or
      assert claims in respect of representations and warranties which are
      expressly referred to and stated in Section 7 as being made by the
      Seller and no further statements, representations, warranties or
      guarantees are made, or deemed to be made, by the Seller, other than
      those expressly and conclusively set forth in Section 7. In particular,
      the Buyer shall not be entitled to rely on the prospective development
      of Vintron, including, but not limited to, business forecasts, expected
      earnings, budgetary accounting and the like (including the statements
      made in the Business Plan or any other business plans or budgets of
      Vintron) prepared in regard to Vintron.


9.4   DETERMINATION OF DAMAGES; CONSEQUENTIAL DAMAGES. The Seller shall not be
      liable for any reputation damages. Any damage shall be calculated
      strictly on Vintron's level and shall, if applicable, be determined by
      applying a discount factor on a discounted cash flow basis, calculated
      on the basis of the 12-months-EURIBOR plus 250 basis points
      ["Basispunkte"], not taking into consideration circumstances and/or
      considerations of the Buyer, such as (but not limited to) the multiple
      which the Buyer applied when valuating the Business. For the avoidance
      of doubt, it is clarified that the Buyer shall in no event be entitled
      to bring or assert any claim and the Seller shall not be held liable for
      any consequential damages ["mittelbare Schaeden" bzw. "Folgeschaeden"] of
      the Buyer, in particular (but not limited to) loss of profit by the
      Buyer.



<PAGE>   27

                                                                             27





9.5   NO ENVIRONMENTAL WARRANTIES. Any environmental pollution, i.e. pollution
      or other strains of soil, groundwater, air surface, facilities or
      buildings shall solely and exclusively be subject of the terms and
      conditions of the indemnification clause as set forth in Section 10.1.
      The Seller shall not be liable for (i) Environmental Pollution or (ii)
      other claims relating to pollution or other strains of soil,
      groundwater, soil air, surface water, facilities or buildings of
      whatever nature and based on whatever legal grounds, and neither of the
      representations or warranties made in Section 7 are made, or deemed to
      be made, with regard to environmental pollution, unless provided for
      otherwise in Section 10.1.


9.6   NO DOUBLE RECOVERY. The Buyer shall not be entitled to bring or assert
      any claims pursuant to Section 9 if and to the extent (i) the annual
      accounts contain a provision for the matter violating the respective
      representation and warranty, if the amount of loss, damage, expense or
      liability incurred is less than the amount contained in such specific
      provision or (ii) recovery, payment or compensation for a specific
      matter violating the respective representation and warranty has already
      been obtained by the Buyer or Vintron in whatever manner and from
      whatever source, so as to avoid the Buyer receiving double recovery for
      such specific matter. For the avoidance of doubt it is further clarified
      that Section 254 of the German Civil Code shall be applicable.


9.7   EXCLUSIVE REMEDIES. The rights of the Buyer pursuant to Section 9 shall
      be the sole and exclusive remedies for the breach of any of the
      provisions in Section 7, any other claim or right, whether for damages,
      reduction of price ["Minderung"] or rescission ["Wandelung",
      "Ruecktritt"], prior to or after the Closing, for culpa in contrahendo,
      clausula rebus sic stantibus or on any other legal basis shall be - to
      the extent legally permissible - excluded, except for claims based upon
      wilful misconduct ["Vorsatz oder Arglist"].


9.8   RESCISSION. If the clearance by the European Commission or the German
      Federal Cartel Office, as the case may be ("CARTEL APPROVAL"), has not
      been granted within (6) six months after the date hereof, then the
      Seller or the Buyer may rescind this Agreement. In such case, the
      Parties will carry their respective costs incurred in connection with
      this Agreement individually, waiving any claims they may have hereunder
      or which they may have become entitled to in the course of negotiations
      leading to the signing hereof against one another to the extent that the
      other Party has performed and complied in all material respects with
      their obligations under the Agreement. The Seller or the Buyer shall
      further be entitled to rescind this Agreement if any of the other
      conditions precedent pursuant to Section 3 are not



<PAGE>   28

                                                                             28






      fulfilled or waived (x) within (3) three months after the date hereof or
      (y) within 10 (ten) business days after the Cartel Approval has been
      granted, whichever occurs later.


                                  SECTION 10
                               INDEMNIFICATION


10.1  ENVIRONMENTAL. In respect of claims resulting from the pollution of
      soil, soil air ("Bodenluft"), groundwater, surface water, buildings or
      facilities, which cause adverse changes of the condition of the soil
      resulting in dangers, substantial disadvantages or substantial nuisance
      for the individual or the public ["Schaedliche Bodenveraenderung" i.S.d.
      Section 2 BBodSchG] or any other dangers for the individual or the
      public ["Gefahren fuer den Einzelnen oder die Allgemeinheit"] pursuant to
      other applicable German laws (the "ENVIRONMENTAL POLLUTION") including
      claims of any Governmental authority or of InfraServ, or any third
      party, the Buyer or Vintron, as the case may be, shall be indemnified in
      accordance with the terms and conditions provided under this Section
      10.1 only.


      "ENVIRONMENTAL LIABILITIES" shall be all costs (including third party
      claims) incurred in connection with the investigation, elimination or
      remediation of Environmental Pollution in order to comply with (i) final
      ["bestandskraeftig"] or immediately enforceable ["sofort vollziehbar"]
      administrative acts ["Verwaltungsakte"], (ii) final ["rechtskraeftig"]
      court decisions, or (iii) agreements entered into, in order to avoid
      acts and decisions as defined in (i) and (ii), with the consent of the
      Seller, with administrative authorities, or neighbours, (iv) the need to
      remediate an imminent danger for the well-being or health ["Gefahr im
      Verzug fuer Leib oder Leben"], or, to the extent that an omission of
      taking immediate action would result in a criminal offence, groundwater
      ["Grundwasser"], in each case if and to the extent that such
      Environmental Liabilities are based on the laws and regulations
      applicable or formally published by the relevant authorities as of the
      Closing Date. Vintron or the Buyer, as the case may be, shall be
      indemnified and held harmless from the Environmental Liabilities in
      accordance with the provisions following hereunder by the Seller:


      The indemnification by the Seller includes, but is not limited to,
      claims brought by InfraServ pursuant to paragraph 6 of the partnership
      agreement of InfraServ in



<PAGE>   29

                                                                             29




      respect of additional cash contributions ["Nachschuesse"] as may be
      requested to be assumed by Vintron, as set forth in lit. (c) of this
      Section 10.1


      In all cases of pollution or other strains of soil air, groundwater,
      air, surface water, facilities or buildings occurred prior to the
      Closing Date, the Buyer and Vintron shall be authorised to raise claims
      under, and in accordance with, the terms and conditions of this Section
      10.1 only. Section 7.19 remains unaffected in the event a violation of
      Section 7.19 results in the occurrence of such pollution and/or strains
      after the Closing Date. Subject to the terms and conditions as set forth
      in this Section 10.1 the Seller shall indemnify and hold harmless
      Vintron or the Buyer, as the case may be, as follows:


      (a)   SUBSTANCES NO LONGER IN USE. If and to the extent the
            Environmental Pollution is caused by substances which on or after
            the Closing Date are not used by Vintron and unless the
            Environmental Pollution is caused after the Closing Date, the
            Seller shall indemnify and hold harmless Vintron for any
            Environmental Liabilities which become due


            (i)   in the period from the Closing Date through 31 December 2009
                  by 100%,


            (ii)  in the period from 1 January 2010 through 31 December 2010
                  by 80%,


            (iii) in the period from 1 January 2011 through 31 December 2011
                  by 60%,


            (iv)  in the period from 1 January 2012 through 31 December 2012
                  by 40%, and


            (v)   in the period from 1 January 2013 through 31 December 2013
                  by 20%.


            Any Environmental Liabilities which become due after 31 December
            2013 shall be assumed by Vintron or the Buyer, and Vintron and the
            Buyer shall indemnify and hold harmless the Seller from any such
            Environmental Liabilities, and any Environmental Liabilities not
            to be borne by the Seller pursuant to the sliding scale set forth
            above, asserted against them. For the purpose of allocating the
            Environmental Liabilities to the respective time periods set forth
            in the above sliding scale any Environmental Liabilities become
            due


            -     in case of Environmental Liabilities in the meaning of
                  Section 10.1 paragraph 2 (i) and (ii) at the time when the
                  Buyer has notified the Seller



<PAGE>   30

                                                                             30




                  in writing and in substantiated form of the nature and scope
                  of the respective Environmental Pollution, provided,
                  however, that the administrative act ("Verwaltungsakt") is
                  issued within (8) eight months (taking into account any
                  possible negotiation period under the next recital)
                  following such notification, and provided further that the
                  Buyer and Vintron have fully complied with their obligations
                  pursuant to (i) (Further Condition) (iv) below, otherwise at
                  the time when the administrative act ["Verwaltungsakt"] is
                  issued;


            -     in case of Environmental Liabilities in the meaning of
                  Section 10.1 paragraph 2 (iii) at the time when the Buyer
                  has notified the Seller in writing and in substantiated form
                  of the nature and scope of the respective Environmental
                  Pollution, provided, however, that any agreement between
                  Buyer and Seller on an indemnification is achieved within
                  (4) four months following such notification;


            -     in case of Environmental Liabilities in the meaning of
                  Section 10.1 paragraph 2 (iv) at the time when the Buyer has
                  notified the Seller in writing and in substantiated form of
                  the nature and scope of the respective Environmental
                  Pollution, provided, however, that any remediation has been
                  commenced within (4) four months following such
                  notification.


      (b)   SUBSTANCES STILL IN USE. If and to the extent the Environmental
            Pollution is caused by substances which at the Closing Date are
            still in use by Vintron, and provided that the Environmental
            Pollution is caused prior to the Closing Date, the Seller shall
            indemnify and hold harmless Vintron or the Buyer for any
            Environmental Liabilities which become due


            (i)     in the period from the day hereafter through 31 December
                    2001 by 90%,


            (ii)    in the period from 1 January 2002 through 31 December 2002
                    by 80%,


            (iii)   in the period from 1 January 2003 through 31 December 2003
                    by 70%,


            (iv)    in the period from 1 January 2004 through 31 December 2004
                    by 60%,


            (v)     in the period from 1 January 2005 through 31 December 2005
                    by 50%,


            (vi)    in the period from 1 January 2006 through 31 December 2006
                    by 40%,

<PAGE>   31

                                                                             31





            (vii)   in the period from 1 January 2007 through 31 December 2007
                    by 30%,


            (viii)  in the period from 1 January 2008 through 31 December 2008
                    by 20%,


            (ix)    in the period from 1 January 2009 through 31 December 2009
                    by 10%.


            Any Environmental Liabilities which become due after 31 December
            2009 shall be assumed by Vintron or the Buyer, and Vintron and the
            Buyer shall indemnify and hold harmless Seller from any such
            Environmental Liabilities, and any Environmental Liabilities not
            to be borne by the Seller pursuant to the sliding scale set forth
            above, asserted against them.


            For the purpose of allocating the Environmental Liabilities to the
            respective time periods set forth in the above sliding scale the
            last sentence of Section 10. 1 (a) above shall apply.


      (c)   Notwithstanding the provisions under (a) and (b), in the event
            that Vintron, as a limited partner of InfraServ, is requested to
            assume additional cash contributions ["Nachschuesse"] pursuant to
            Section 6 of the Partnership Agreement ["Gesellschaftsvertrag"] of
            InfraServ for Environmental Pollution not directly attributable to
            the Business, which become due as from 1 January 2010, and unless
            the Environmental Pollution is caused after the Closing Date, the
            Seller shall indemnify and hold Vintron harmless from


            (i)   contributions which become due in the period from the
                  Closing Date through 31 December 2009 by 100%


            (ii)  contributions which become due in the period from 1 January
                  2010 through 31 December 2010 by 80%,


            (iii) contributions which become due in the period from 1 January
                  2011 through 31 December 2011 by 60%,


            (iv)  contributions which become due in the period from 1 January
                  2012 through 31 December 2012 by 40%,


            (v)   contributions which become due in the period from 1 January
                  2013 through 31 December 2013 by 20%.


<PAGE>   32

                                                                             32




            There shall be no obligation of the Seller to indemnify Vintron
            for, or hold Vintron harmless from, any additional cash
            contributions which become due after 31 December 2013, and Vintron
            and the Buyer shall indemnify and hold harmless the Seller from
            any such cash contributions, and any cash contributions not to be
            borne by the Seller pursuant to the sliding scale set forth above,
            requested from the Seller.


      (d)   PROCEEDINGS AND RESTRICTIONS. Vintron or the Buyer, as the case
            may be, shall (i) inform the Seller promptly (in any case in good
            time prior to expiration of any appeal periods) of the assertion
            of any claim or any demand, action, proceeding or judgment related
            to or in connection with Environmental Pollution and the
            Environmental Liabilities, (ii) take any reasonably necessary
            action in the defence of such claim, action, proceeding or
            judgment, if instructed by the Seller, (iii) fully co-operate with
            the Seller in the defence or settlement in respect of the
            Environmental Liabilities, (iv) grant advantage to the Seller to
            participate in the defence of any claim, suit action or
            proceeding, and (v) make no admission to the claimant or
            settlements without its prior written approval. In particular, the
            Buyer undertakes to inform, and shall cause that Vintron
            undertakes to inform, the Seller without undue delay of any
            environmental pollution which has been notified to the relevant
            Governmental authorities. Furthermore, the Buyer shall inform and
            consult or cause Vintron to inform and consult with Seller before
            corrective actions with regard to environmental pollution,
            including investigation and transportation, storage and treatment
            of polluted soil, water or buildings, are taken. If the Buyer or
            Vintron are obliged to act immediately in a case of imminent
            danger ["Gefahr in Verzug"] the Buyer or Vintron shall be obliged
            to act with the care of a prudent businessman before informing and
            consulting with the Seller. The Seller shall be given the
            opportunity to comment on, participate in and review any reports
            on or relevant investigations, orders or other measures which may
            with a reasonable likelihood give rise to Environmental
            Liabilities, and the Buyer shall ensure that the Seller receives
            without undue delay copies of all such documents.


      (e)   ARBITRATOR. In the case of Section 10.1 (b) the following shall
            apply:


            If the Seller and the Buyer cannot agree as to whether or to what
            extent the Environmental Pollution occurred prior or after the
            Closing Date, the Seller and the Buyer shall jointly appoint an
            independent environmental expert (the





<PAGE>   33

                                                                             33





            "Expert"). If the parties cannot, within 6 weeks after the Seller
            receiving notice of the Environmental Pollution by the Buyer,
            agree on the Expert, a neutral and reputable Expert shall be
            determined by the president of the Industrie- und Handelskammer
            Frankfurt. The costs of the Expert and the determination of the
            Expert shall be borne by the Parties to the extent the Expert's
            determination is detrimental to the respective Parties.


            The Expert shall finally determine whether the Environmental
            Pollution occurred prior of after the Closing Date. If the Expert


            (A)   determines that the Environmental Pollution occurred prior
                  to the Closing Date, then the sliding scale referred to
                  above under 10.1 (b) shall apply;


            (B)   determines, that the Environmental Pollution occurred on or
                  after the Closing Date, then the Seller shall not be liable
                  at all;


            (C)   cannot determine whether the Environmental Pollution
                  occurred prior or after the Closing Date, then the sliding
                  scale referred to above under 10.1 (b) shall apply.


            The Expert shall base his determination on a thorough
            investigation of the pollution, its circumstances and the safety
            and environmental protection standards applied by Vintron. The
            Buyer shall procure that Vintron will provide the Expert with all
            information which he deems necessary for his determination and
            grant access to Vintron's sites as may be required. If the Expert
            states that he cannot make a determination because Vintron has not
            complied with its obligations set forth above, then the
            Environmental Pollution shall be deemed to have occurred after the
            Closing Date.


      (f)   DE MINIMIS THRESHOLD. The Seller shall only be liable for
            indemnification under this Section if, and solely to the extent
            that, the individual Environmental Liability exceeds DM 100,000
            (Deutsche Mark one hundred thousand) and the aggregate
            Environmental Liability in each calendar year exceeds DM 500,000
            (Deutsche Mark five hundred thousand).


      (g)   INDEMNIFICATION CAPS. There is no special cap of indemnification
            under this Section 10.1. Instead the Total Seller Liability Amount
            as defined in Section 11.2 also applies to the indemnification
            under this Section 10.1.


<PAGE>   34
                                                                             34


      (h)   NO DOUBLE RECOVERY. Section 9.7 shall apply mutatis mutandis,
            provided that in this respect, if any insurance coverage for
            Environmental Liabilities, if existing, should have been reduced
            after the Closing Date, such amounts shall be taken into account
            to the favour of the Seller, which would have been recovered under
            the insurance policies in force as of the Closing Date, unless
            such insurance coverage cannot be obtained by an insurance
            company, or only be obtained at conditions which are substantially
            unfavourable compared to the current conditions.


      (i)   FURTHER CONDITIONS. The obligation of the Seller to indemnify
            Vintron or the Buyer, as the case may be, pursuant to this Section
            10.1 does not apply to the extent the Environmental Liabilities
            have, directly or indirectly, been caused or increased by the fact
            that either Vintron or the Buyer or any other person conducting
            the Business or other businesses at the respective sites after the
            Closing Date


            (i)   has not complied with any applicable laws, regulations,
                  orders, notices including applicable standards for security
                  and environmental protection (provided that such
                  non-compliance is not caused by a non-compliance by the
                  Seller or Vintron prior to the Closing Date which could not
                  be remedied by Vintron or the Buyer within reasonable time);
                  or


            (ii)  failed to mitigate damages pursuant to Section 254 German
                  Civil Code; or


            (iii) changes the use of the sites, in particular non-temporarily
                  (exceeding a period of (6) six months) partly or completely
                  ceases plant operations, or parts thereof, of the Business
                  of Vintron; or


            (iv)  has disclosed to any governmental authority ["Behoerde"]or
                  any private unaffiliated third party (excluding advisors and
                  agents of Vintron and/or the Buyer), directly or indirectly,
                  environmental pollution, or taken any other exploratory or
                  investigative measures, except where such disclosure or
                  measure was required to be made by a final
                  ["bestandskraeftig"] or immediately enforceable ["sofort
                  vollziehbar"] administrative act ["Verwaltungsakt"] or
                  unless such disclosure was required by law.


10.2  TAX INDEMNIFICATION. With regard to any taxes and ancillary taxes
      ["Steuern und steuerliche Nebenleistungen"] within the sense of Section
      3 AO ["Abgabenord-



<PAGE>   35
                                                                             35



      nung"] and including social security contributions (the "TAXES")
      concerning the period prior to the Effective Date the Parties agree as
      follows:


      (a)   TAX ASSESSMENTS. Concerning the period prior to the Effective Date
            the Parties shall co-operate with regard to any Taxes. The Buyer
            shall notify the Seller promptly about any order announcing a Tax
            or relevant other audit that may partially or fully extend any
            Taxes relating to Vintron for any taxable periods
            ["Veranlagungszeitraeume"] ending before the Effective Date (the
            "TAXABLE PERIOD"). Copies of such order shall promptly be
            forwarded to the Seller by registered mail ["Einschreiben mit
            Rueckschein"]. The Seller shall be fully authorised to participate
            in the negotiations with tax and other authorities concerning such
            Taxes regarding the Taxable Period. The Seller is entitled to lead
            such negotiations and the Buyer will keep the Seller closely
            informed about any audits or investigations of the relevant
            authorities in an appropriate manner. The Seller shall be
            authorised to appeal at its own cost in Vintron's name against any
            Tax or other assessment notice concerning the Taxable Period.


      (b)   TAX INDEMNIFICATION. Upon receipt of the relevant Tax assessment
            notice by either the Buyer or Vintron, the Seller shall be liable
            for the payment of, and shall indemnify and hold harmless the
            Buyer or Vintron, as the case may be, from all Taxes assessed
            against Vintron by any tax authority for any business year within
            the Taxable Period which exceed reserves and provisions for Taxes
            for the specific business years as reflected in the financial
            statements of Vintron (the "SURPLUS TAXES"). The Buyer shall vice
            versa procure that Vintron shall compensate the Seller for all
            reduced Taxes ["Mindersteuern"] concerning the Taxable Period
            which fall short of the reserves and provisions for Taxes for the
            Taxable Period as reflected in the financial statements (the
            "Reduced Taxes").


      (c)   DISPUTES. In the event of any disagreements or disputes arising in
            respect of, or in connection with, the determination of the
            Surplus Taxes or the Reduced Taxes, the Independent Auditor shall
            on request of either of the Parties determine the respective
            Surplus Taxes and/or Reduced Taxes in a binding manner. The costs
            incurred by the assignment of the Independent Auditor shall be
            borne by the Parties in proportion the determination being
            detrimental to the respective Party's interest.


<PAGE>   36
                                                                             36





10.3  VCM SUPPLY AGREEMENT. Seller guarantees that Vintron will be provided
      with sufficient VCM up to 155 kt from third parties or from Seller in
      order to satisfy its obligations under the VC-Liefervertrag as described
      in Section 3.1 a) (until 31 December 2001) by undertaking to compensate
      Vintron as follows: (i) In the event of a lack of supply, the Seller has
      to pay a penalty to Vintron (payable to Vinnolit) equal to the lost
      contribution margin of Vinnolit which is fixed between the parties at an
      amount of 450 DM/t VCM (in aggregate the "LOST CONTRIBUTION MARGINS");
      and (ii) in the event that Vintron incurs losses resulting from the VCM
      procurement and consecutive sale pursuant to the VC-Liefervertrag at
      prices as determined pursuant to the VC-Liefervertrag described in
      Section 3.1 a) ( the "VCM LOSSES"), Seller shall compensate the VCM
      Losses up to a maximum amount of DM 450 DM/t VCM for each single
      purchase transaction, provided, however, that in each of the cases (i)
      and (ii) payments by Seller shall have to be made only to the extent the
      sum of the Lost Contribution Margins and the VCM Losses exceeds in
      aggregate DM 20.4 million as stated in the business plan. Buyer shall
      procure that Vintron sources VCM only after consultation with, and
      approval by, Seller or, at Seller's option, Celanese AG & Co.
      Procurement Olefin KG.


10.4  SHUT DOWN LIABILITIES. Seller submitted to Buyer documentation according
      to which Vintron as part of the contribution of the chlorine
      electrolysis products business Huerth-Knapsack to Vintron by Seller might
      have assumed indemnification obligations of Seller towards the mono
      chlorine acetic acid business currently controlled by Clariant GmbH in
      the event of a shut down of the chlorine-electrolysis plant in
      Huerth-Knapsack ("Celanese Obligation").


      Seller shall be liable for the payment of and shall indemnify and hold
      harmless the Buyer and Vintron for any and all liabilities, costs and
      expenses resulting from the assumption of the Celanese Obligations.


                                  SECTION 11
                          LIMITATION OF LIABILITIES


11.1  DE MINIMIS THRESHOLDS. No claim may be brought by the Buyer in regard to
      this Agreement unless (i) an individual claim exceeds DM 250,000
      (Deutsche Mark two hundred fifty thousand) and (ii) the aggregate claims
      exceed DM 1,000,000 (Deutsche Mark one million) ("De minimis
      Thresholds"). In the event that the Buyer's claims exceed the De minimis
      Thresholds, only the amount of the claims



<PAGE>   37

                                                                             37




      actually exceeding the De minimis Thresholds may be recovered by the
      Buyer ["Freibetraege"]. The foregoing De minimis Threshold shall not
      apply to any claims regarding defects of ownership of the Shares
      pursuant to Section 7.3 and 7.4.


11.2  TOTAL CAP ON CLAIMS. The total liability the Seller may become subject
      to under this Agreement (for the avoidance of doubt including, but not
      limited to, any claims under Section 10.1) is limited to a total
      aggregate amount of DM 70,000,000 (Deutsche Mark seventy million) (the
      "TOTAL SELLER LIABILITY AMOUNT"). This shall neither apply to any
      defects of ownership of the Shares pursuant to Section 7.3 and 7.4, nor
      to the tax indemnification pursuant to Section 10.2. This shall also not
      apply to the indemnification obligations under Section 10.4 (Shut Down
      Liabilities).


                                  SECTION 12
                       SURVIVAL OF CLAIMS AND REMEDIES


12.1  EXPIRATION PERIOD. Except as otherwise provided for in this Agreement,
      all representations and warranties made in Section 7 shall terminate and
      expire ["verjaehren"] (18) eighteen months after the date hereof.


12.2  DEFECTS IN OWNERSHIP OF SHARES. Any claims brought in respect of
      representations and warranties regarding defects in the ownership of the
      Shares as set forth in Section 7.3 or 7.4 shall terminate and expire (5)
      five years after the date hereof.


12.3  ENVIRONMENTAL INDEMNIFICATION. Any claims of the Buyer brought in
      respect of the indemnification from Environmental Liabilities pursuant
      to Section 10.1 shall terminate and expire (6) six months after the
      Environmental Liabilities become due within the meaning of the last
      sentence of Section 10.1.a) and 10.1 b), respectively.


12.4  TAX INDEMNIFICATION. Any claims of the Buyer under Section 10.2 shall
      terminate and expire (6) six months after either the Buyer or Vintron,
      as the case may be, has received the final and binding tax assessment
      (including adjustment assessments) by the taxing authority.


12.5  INTERRUPTION. Upon receipt of written notice on a specific claim in
      writing by the Buyer vis-a-vis the Seller, which details the alleged
      basis for such claim shall mean that the limitation period shall be
      interrupted ["unterbrochen"] with respect to such claims, always
      provided that the Buyer takes legal action ["Klage erheben"] within (3)
      three months after such notification.





<PAGE>   38


                                                                             38

                                  SECTION 13


                          [intentionally left blank]


                                  SECTION 14
                           COVENANT NOT TO COMPETE


14.1  COVENANT NOT TO COMPETE. For a term of (2) two years after the date
      hereof, the Seller shall not, unless otherwise provided in Section 14.2
      below, (i) engage in or carry out any new business activities which
      represent competition to the Business nor (ii) acquire a controlling
      interest of more than 50% in the equity or in the voting rights, neither
      directly nor indirectly, in entities which compete with the Business, in
      each case on the relevant product and geographic markets on which
      Vintron has been active at the date hereof.


14.2  EXEMPTIONS. The following activities are exempt from the restrictions
      set out in Section 14.1:


      (a)   the existing business activities of the Seller as presently
            conducted;


      (b)   acquiring an controlling interest in an entity, or any assets
            thereof, which is not in the first place and not mainly engaged in
            activities competing with the Business. To the extent legally
            possible, the Seller shall use its best efforts that in the event
            of a sale of the PVC part of the acquired business such PVC part
            of the acquired business shall be offered to the Buyer prior to an
            offer to third parties;


      (c)   acquiring all or part of the assets of the chlorine chemicals
            business at the facilities in Frankfurt am Main-Hoechst, such
            business having been sold by Seller to LII Europe GmbH;


      (d)   any captive use of the Seller, i.e. production which is not sold
            to third parties outside the group of affiliated enterprises.


                                  SECTION 15
                        FURTHER COVENANTS OF THE BUYER


RELEASE FROM COLLATERAL. The Buyer shall procure that the Seller and the
Seller's Affiliates, as the case may be, are released from any collateral not
exceeding DM



<PAGE>   39

                                                                             39



1,000,000 (Deutsche Mark one million), provided by them to the benefit of
Vintron and shall, on the Seller's first demand, indemnify the Seller and the
Affiliates, as the case may be, in respect of any and all claims resulting
from such collateral.


                                  SECTION 16
                    CARTEL CLEARANCE, OTHER COVENANTS OF THE PARTIES


16.1  CO-OPERATION REGARDING CARTEL AUTHORITIES. The Parties agree to
      co-operate fully with a view to obtaining unconditional clearance by the
      German Federal Cartel Office and/or the European Commission, whichever
      is required for the consummation of the transactions contemplated
      hereby, without delay. The Buyer's counsel shall without undue delay,
      however, if possible, not later than (10) ten working days after the
      date hereof, prepare all files with regard to the application to the
      relevant cartel authorities, which shall be reviewed by the Seller. The
      charges of the respective cartel authorities are to be borne by the
      Buyer. The cost of the Seller's counsel are to be borne by the Seller
      and the cost of the Buyer's counsel are to be borne by the Buyer.


16.2  PARTIES' EFFORTS TO CLOSE. The Seller and the Buyer undertake to use all
      reasonable efforts to ensure fulfilment and compliance with all the
      conditions and obligations as set forth in this Agreement and procure
      any necessary official authorisations as may be required to consummate
      the transactions contemplated hereby as soon as practicable as of the
      date hereof so as to secure Closing and full completion of all the
      transactions contemplated hereby at the earliest date possible.


                                  SECTION 17
                              GENERAL PROVISIONS


17.1  NOTICES. All notices, requests, claims, demands and other communications
      hereunder shall be in writing and in the German or the English language
      and shall be given or made (and shall be deemed to have been duly given
      or made upon receipt) by delivery in person, by telefax or by registered
      mail ["Einschreiben mit Rueckschein"] to the respective Parties at the
      following addresses:


      (a)   if to the Seller:


            Celanese Chemicals Europe GmbH
            c/o Celanese AG

<PAGE>   40
                                                                             40




            Frankfurter Str. 111
            61476 Kronberg
            Telecopy: +49/69 305 82731
            Attention: General Counsel Celanese AG


            with a copy to


            Hengeler Mueller Weitzel Wirtz
            Trinkausstrasse 7
            40213 Duesseldorf
            Telecopy: +49/211-132641
            Attention: Dr. Rainer Krause


      (b)   if to the Buyer:


            Vinnolit GmbH & Co. KG
            Carl-Zeiss-Ring 25
            85737 Ismaning
            Telecopy:  +49/89 69103-119
            Attention: Managing Director ["Geschaeftsfuehrer"]


            with copies to:


            Advent International Corporation
            75 State Street
            Boston, MA 02109
            USA
            Telecopy: +1/617951-0571
            Attention: Mrs. Janet Hennessy and Mr. Tom Lauer


            and to


            Baker & McKenzie Doeser Amereller Noack
            Bethmannstr. 50-54
            60311 Frankfurt am Main
            Telecopy: +49/6929908-108
            Attention: Dr. Joerg Kirchner and Mr. Christian Brodersen
<PAGE>   41

                                                                             41

      A change in the person or address of the aforementioned addressees shall
      become effective for the other Party only (1) one month after having
      been informed on such change by written notice.


17.2  PUBLIC ANNOUNCEMENTS. No Party to this Agreement shall make, or cause to
      be made, any press releases or public announcements in respect of this
      Agreement or the transactions contemplated hereby or otherwise
      communicate with any news media without prior notification to, and
      consultation with, the other Party, and the Parties shall co-operate as
      to the timing and contents of any such announcement.


17.3  HEADINGS. The descriptive headings contained in this Agreement are for
      convenience of reference only and shall not affect in any way the
      meaning or interpretation of this Agreement.


17.4  GERMAN TERMS. The terms set forth in this Agreement in German language
      shall take precedence over corresponding English terminology, if any, in
      interpreting the contents of the pertinent contractual provision and be
      interpreted in accordance with the meaning of that German term under
      German law and as would be customary in German language contracts.


17.5  COSTS. Except as otherwise specified in the Agreement, all costs and
      expenses, including, without limitation, fees and disbursements of
      counsel, financial advisors and accountants, incurred in connection with
      the Agreement and the transactions contemplated hereunder shall be paid
      by the Party incurring such costs and expenses. Any and all notary
      public fees and costs and expenses with regard to the execution and
      performance of the Agreement and the transactions contemplated hereunder
      shall be borne by the Buyer.


17.6  ENTIRE AGREEMENT. The Agreement together with any documents referred to
      herein or incidental to the Agreement by the parties constitutes the
      entire Agreement between the parties hereto and replaces and supersedes
      any agreements or arrangements made previously in regard to the subject
      matter hereof.


17.7  AMENDMENTS. Any amendments, authorisations or variations of the
      Agreement, including this Section 17.7, require written form (unless
      notarisation is required) in order to be valid and effective.


17.8  SEVERABILITY. If any term or other provision of the Agreement is
      invalid, illegal or incapable of being enforced by any rule of law or
      public policy, all other conditions


<PAGE>   42

                                                                             42







      and provisions of the Agreement shall nevertheless remain in full force
      and effect so long as the economic or legal substance of the
      transactions contemplated hereby is not affected in any manner
      materially adverse to any Party. Upon such determination that any term
      or other provision is invalid, illegal or incapable of being enforced,
      the Parties hereto shall negotiate in good faith to modify the Agreement
      so as to effect the original intent of the Parties as closely as
      possible in an acceptable manner in order that the transactions
      contemplated hereby are consummated as originally contemplated to the
      greatest extent possible.


17.9  GOVERNING LAW. PLACE OF VENUE. The validity, performance and enforcement
      of the Agreement shall be governed by German law. Exclusive place of
      venue shall be Frankfurt am Main.


                                                      (continued on next page)


<PAGE>   43


IN WITNESS THEREOF this Notarial Deed including the Schedules hereto


      with the exception of certain lists of items, titles, rights and
      obligations contained in Schedules 7.16 and 7.17, in respect of which
      the persons appearing waived the right to have them read aloud and which
      instead have been presented to the persons appearing, were acknowledged,
      approved and signed on each page by the persons appearing,


has been read aloud to the persons appearing and was confirmed and approved by
the persons appearing. The persons appearing then signed this Deed. All this
was done at the day herebelow written in the presence of me, the Notary
Public, who also signed this Deed and affixed my official Seal.


Basel, this 19th (nineteenth) and 20th (twentieth) day of May 2000 (two
thousand)