**Exhibit 10.66****FIRST PRIORITY EQUITY INTEREST PLEDGE AGREEMENT**This First Priority Equity Interest Pledge Agreement (*Contrato de Prenda sobre Partes Sociales enPrimer Lugar y Grado*) is entered into on this 12th day of September, 2007 (the“**Agreement**”), by and among Rio Vista Operating Partnership, L.P. (“**RVOP**”), PennOctane International, LLC (“**POI**”) (RVOP and POI are collectively referred herein as“**Pledgors**”), and TransMontaigne Product Services, Inc. (“**TPSI**”) and TransMontaignePartners L.P. (“**TLP**”) (TPSI and TLP are collectively referred herein as **Pledgees**”)with the acknowledgment of Penn Octane de Mexico, S. de R.L. de C.V. (“**Issuer**”), inaccordance with the following Preliminary Statements, Representations and Clauses.**Preliminary Statements**WHEREAS:A. TLP and RVOP are parties to a Letter of Intent (the “**LOI**”) dated September 12,2007 pursuant to which TLP is paying RVOP a refundable deposit in the amount of Six MillionFive Hundred Thousand Dollars ($6,500,000.00) (the “**Deposit**”) in connection with theproposed purchase of certain of RVOP’s assets.B. TPSI and RVOP are parties to that certain Restated and Amended Promissory Note (the“**Promissory Note**”) in the principal sum of One Million Dollars ($1,000,000.00), datedSeptember 12, 2007, pursuant to which RVOP has agreed to pay to TPSI the principal sumtogether with interest (the “**Loan**”) pursuant to the terms and conditions set forth inthe Promissory Note.C. The obligations of RVOP under the LOI to refund the Deposit and under the PromissoryNote to repay the Loan (collectively, the **“****Secured Obligations****”**) are secured by asecurity interest in specified collateral as set forth in that certain Restated and AmendedSecurity Agreement (as amended, restated, supplemented or otherwise modified from time totime, the “**Security Agreement**”), dated September 12, 2007, entered into by and amongRVOP and the Pledgees.D. Pursuant to the obligations assumed by RVOP under the RVOP Agreements, and as securityfor the timely payment in full when due (whether at stated maturity, by acceleration orotherwise) of the Secured Obligations, (i) Pledgors shall execute and deliver this Agreementin order to grant a perfected first priority pledge and security interest to Pledgees in andto 100% (one hundred percent) of the issued and outstanding corporate capital of Issuer, and(ii) RVOP will cause certain other agreements (the **“****Other Mexican Security Documents**”)to be executed and delivered granting a perfected first priority pledge and security interestto Pledgees in and to one hundred percent of the corporate capital of Termatsal, S.de R.L. de C.V. and assigning certain rights and actions that RVOP is entitled to inconnection to the equity interests issued by Tergas, S. de R.L. de C.V. (“**Tergas**”).
 
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E. The LOI, the Promissory Note, the Security Agreement and the Other Mexican SecurityDocuments are referred to herein as the “**RVOP Agreements**”). Capitalized terms usedherein and not defined herein shall have the meaning assigned to such terms in the SecurityAgreement.**Representations and Warranties**I. The Pledgors hereby represent and warrant that: (a) Pledgors are duly organized and validly existing under the laws of itsjurisdiction of incorporation, with full legal capacity and corporate authority toenter into, deliver and perform its obligations under this Agreement; (b) RVOP is the sole, legal and beneficial owner of 1 (one) equity interestSeries B-1 representing MxP$49,950.00 pesos, legal tender of Mexico (“**Pesos**”),of the fixed portion of the corporate capital of Issuer, which represents 99% (ninetynine percent) of the total issued and outstanding corporate capital of Issuer; (c) POI is the sole, legal and beneficial owner of 1 (one) equity interest SeriesB-1 representing MxP$50.00 Pesos, of the fixed portion of the corporate capital ofIssuer, which represents 1% (one percent) of the total issued and outstandingcorporate capital of Issuer; (d) As security for the payment and performance, as the case may be, in full ofthe Secured Obligations, Pledgors wish to grant a perfected first priority pledge andsecurity interest in and to their equity interests of the corporate capital of Issuer,which represent 100% (one hundred percent) of the issued and outstanding corporatecapital of Issuer, in favor of Pledgees (the “**Pledged Equity Interests**”); (e) the Pledged Equity Interests have been duly and validly issued by Issuer andare fully subscribed and paid for; (f) the Pledged Equity Interests are free and clear of any Liens (as hereinafterdefined), encumbrances or options or any other ownership limitations or preemptiverights of any kind, except for the pledge created hereunder or as otherwise permittedby the RVOP Agreements and except for thepreferential rights of the associates of Issuer as provided in the bylaws of Issuerand expressly provided by Law;
 
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 (g) to their knowledge the Pledged Equity Interests are not subject to anyagreement, other than RVOP Agreements, which restricts assignment, transfer or pledgeof the Pledged Equity Interests, except for the Issuer’s bylaws and as provided byLaw; (h) to their knowledge they do not require any authorization or approval, otherthan the ones obtained, in order to execute this Agreement or to perfect and maintaina perfected first priority security interest over the Pledged Equity Interests, or tocomply with or perform the obligations assumed by them hereunder, which are legal,valid and enforceable against the Pledgors in accordance with their terms; (i) as of the date hereof, there is no pending and, to their knowledge threatenedaction, claim, requirement or proceeding before any court, governmental agency orarbitrator that affects or could affect the legality, validity or enforceability ofthis Agreement or the Pledgors’ legal and valid title to the Pledged Equity Intereststhey own; (j) to their knowledge the entering into and performance of this Agreement doesnot violate, or constitute a breach under (i) any provision of the Pledgors’organizational documents, (ii) any agreement, contract, license, judgment or order towhich any of the Pledgors is a party or by which any of the Pledgors or any of theirassets are bound, or (iii) any law, regulation, circular, order or decree of anybranch of power or governmental entity; (k) the individual executing this Agreement on behalf of the Pledgors has allnecessary power, authority and corporate authorization to execute and deliver thisAgreement on behalf of the Pledgors, and such powers, authority and corporateauthorizations have not been amended, revoked or limited in any way; (l) they are in agreement with pledging the Pledged Equity Interests owned bythem in favor of Pledgees, in accordance with this Agreement; and (m) they acknowledge and agree that the correctness and accuracy of itsrepresentations and warranties set forth herein, the validity, binding effect andenforceability of this Agreement and of the first priority security interest over thePledged Equity Interests created hereby in favor ofPledgees is a material inducement for TLP to make the Deposit and for TPSI to makethe Loan.
 
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II Issuer hereby represents and warrants that: (a) Issuer is a *sociedad de responsabilidad limitada de capital variable*(limitedliability company), duly organized and validly existing under the laws of Mexico; and (b) its representative has all necessary power and corporate authorization toexecute and deliver this Agreement on its behalf, and such powers and corporateauthorizations have not been revoked or limited in any way.NOW, THEREFORE, based on the Preliminary Statements and Representations and Warrantiescontained herein, the parties hereto agree as follows:**Clauses**First. Certain Defined Terms. (a) As used in this Agreement and in addition to any other defined terms in thisAgreement, the following terms shall have the following meanings:“**Agreement**” has the meaning specified in the preamble to this Agreement.“**Business Day**” means any day that is not a Saturday, Sunday or other day on whichcommercial banks in New York City or Mexico, are authorized or required by law to remainclosed.“**Distributions**” has the meaning specified in Clause Fourth (d) of this Agreement.“**Dollars**” means the legal currency of the United States of America.“**Event of Default**” means a default under any of the RVOP Agreements;provided, however, that for purposes of this Agreement, such term shallalso include, without limitation (i) the failure of any Pledgor to comply, perform orobserve any of its obligations hereunder; and (ii) if any representation made by anyPledgor hereunder is false, incorrect or misleading in any respect.“**Governmental Authority**” means the government of the United States of America,Mexico, any other nation or any political subdivision thereof, whether state or local, andany agency, authority, instrumentality, regulatory body, court,central bank or other entity exercising executive, legislative, judicial, taxing,regulatory or administrative powers or functions of or pertaining to the government.
 
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“**Issuer**” has the meaning specified in preamble of this Agreement.“**Law**” means the General Law of Negotiable Instruments and Credit Transactions (*LeyGeneral de Títulos y Operaciones de Crédito*).“**Lien**” means any mortgage, deed of trust, pledge, hypothecation, encumbrance, lien,charge or security interest or any preference, priority or other security agreement orpreferential arrangement of any kind or nature whatsoever (including any conditional saleor other title retention agreement and any capital lease having substantially the sameeconomic effect as any of the foregoing).“**RVOP Agreements**” means the LOI, the Promissory Note, the Security Agreement,this Agreement and the Other Mexican Security Documents.“**Mexico**” means the United States of Mexico.“**Person**” means any natural person, corporation, limited liability company, trust,joint venture, association, company, partnership, Governmental Authority or other entity.“**Pesos**” has the meaning specified in representation I (b) of this Agreement.“**Pledged Equity Interests**” has the meaning specified in representation I (c) ofthis Agreement.“**Pledgors**” has the meaning specified in the preamble to this Agreement.(b) Usage. The definitions in this Clause First shall apply equally toboth the singular and plural forms of the terms defined. Whenever the context may require,any pronoun shall include the corresponding masculine, feminine and neuter forms. Thewords “hereof”, “herein” and “hereunder” and words of similar import, when used in thisAgreement, shall refer to this Agreement as a whole and not to any particular provision ofthis Agreement, unless otherwise expressly indicated, and all references in this Agreementto Clauses, sections, paragraphs, Schedules and Exhibits shall be deemed to be referencesto Clauses, sections, paragraphs, Schedules and Exhibits of this Agreement, unless thecontext shall otherwise require. The words “include”, “includes” and “including” shall bedeemed to be followed by the phrase “without limitation”, unless such phrase otherwiseappears. As used herein and any certificate or other document made or
 
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delivered pursuant hereto, (i) the words “include”, “includes” and “including” shall bedeemed to be followed by the phrase “without limitation”, (ii) the word “incur” shall beconstrued to mean incur, create, issue, assume, become liable in respect of or suffer toexist (and the words “incurred” and “incurrence” shall have correlative meanings), (iii)the words “asset” and “property” shall be construed to have the same meaning and effect andto refer to any and all tangible and intangible assets and properties, including cash,capital stock, securities, revenues, accounts, leasehold interests and contract rights,(iv) references to agreements shall, unless otherwise specified, be deemed to refer to suchagreements as amended, supplemented, restated or otherwise modified from time to time; and(v) references to any statute, law or regulation shall be deemed to include any amendmentsthereto from time to time or any successor statute, law or regulation thereof.Second. Pledge; Grant of First Priority Security Interest.(a) The Pledgors hereby grant an unconditional and irrevocable first priority pledge and securityinterest to Pledgees in and to the Pledged Equity Interests as collateral security for the dueand timely payment, performance and satisfaction when due (whether at stated maturity, byacceleration or otherwise) of any and all Secured Obligations.(b) For purposes of perfecting the first priority security interest over the Pledged EquityInterests pursuant to paragraphs III of Article 334 of the Law, the Pledgors hereby deliver toPledgees for the benefit of the Lender (i) the equity interest certificates representing thePledged Equity Interests; and (ii) a copy of the entry in the associates’ registry book ofIssuer, duly certified by the Legal Representative of Issuer (in the form of **Exhibit“A”** hereto) evidencing that, on the date hereof, the first priority security interest inthe Pledged Equity Interests have been duly recorded in such associates’ registry book; andIssuer hereby acknowledges the pledge created hereby with respect to Pledged Equity Interests.(c) In accordance with Article 337 of the Law, the Pledgors and Pledgees agree that thisAgreement shall serve as receipt (*resguardo*) by Pledgees of the Pledged Equity Interests.(d) The parties agree that, in the event the Pledged Equity Interests are exchanged for newequity interest(s) or reclassified, by Issuer or a third party, the Pledgors and Pledgeesshall, if necessary, undertake any action that may be necessary, including the delivery of newequity interest certificates as collateral to the Pledgees, to maintain the pledge referred toin this Agreement, and such new equity interests shall be deemed for purposes of thisAgreement as Pledged Equity Interests.
 
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(e) The parties agree that any (i) value increase of the Pledged Equity Interests; (ii) issuanceof an additional equity interests of Issuer acquired by the Pledgors or a third party; or(iii) capital increases by Issuer shall be subject to the pledge created hereunder and ifnecessary the Pledgors shall cause to pledge those pursuant to the same terms and conditionsof this Agreement, and for purposes of this Agreement and to the extend permitted byapplicable law, shall be deemed as Pledged Equity Interests.Third. Continuing First Priority Security Interest. The first priority security interestshall be continuing and shall (i) remain in full force and effect until all amounts due under theLOI and the Promissory Note have been paid in full; (ii) be binding upon the Pledgors, theirrespective successors and permitted assigns; and (iii) inure to the benefit of and be enforceableby Pledgees and their respective successors and assigns.Upon payment of the amounts due under the LOI and the Promissory Note, the Pledged Equity Interestsshall be released from the Lien created hereby, and this Agreement and all obligations (other thanthose expressly stated to survive such termination) of Pledgees and the Pledgors shall terminate,all without delivery of any instrument or performance of any act by any party, and all rights tothe Pledged Equity Interests shall revert to the Pledgors. At the request of any of the Pledgorsfollowing any such termination, Pledgees shall deliver to such Pledgors the equity interestcertificates held by Pledgees, and execute and deliver to Pledgors such documents as Pledgors shallreasonably request to evidence such termination and release.Fourth. Voting and Management of the Pledged Equity Interests.(a) Unless an Event of Default shall have occurred and be continuing, the Pledgors will have theright to exercise the voting rights with respect to the Pledged Equity Interests, and suchright can be exercised by Pledgors without need of proxies, instructions, powers or attorneyor other documents or authorizations from Pledgees; provided, however, that novote shall be cast or corporate or other organizational right exercised or other action takenwhich materially impairs all or any material portion of the Pledged Equity Interests or whichviolates any provision of this Agreement.(b) Pledgees herein grant to Pledgors a power of attorney with the authority to exercise thevoting right with respect to the Pledged Equity Interests pursuant to the term and conditionsdescribed in subparagraph (a) above. In addition, Pledgees shall execute and deliver to thePledgors, or cause to be executed and delivered to the Pledgors, any document or instrument asthe Pledgors may reasonably request for the purpose of confirming the authority of Pledgors toexercise the voting and/or consensual rights and powers it is entitled to exercisepursuant to subparagraph (a) above and to receive the cash dividends it is entitled toreceive pursuant to subparagraph (d) below.
 
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(c) Upon the occurrence and during the continuation of an Event of Default, all rights of thePledgors to exercise the voting and other rights and powers that the Pledgors are entitled toexercise pursuant to the foregoing provisions of paragraph (a) of this Clause Fourth shallcease, and all such rights shall thereupon be exercised by Pledgees, who shall have the soleand exclusive right and authority to exercise such voting and other rights and powers;provided that Pledgees shall have the right, but not the obligation, at any time following andduring the continuance of an Event of Default to authorize the Pledgors in writing to exercisesuch rights.(d) Unless an Event of Default shall have occurred and be continuing, the Pledgors shall bepermitted to receive cash dividends, amortizations, profits, capital reimbursements, sums upondissolution and liquidation of Issuer and other distributions distributed that correspond tothe Pledged Equity Interests (the “Distributions”).(e) Upon the occurrence and during the continuation of an Event of Default, Issuer shall deliverto Pledgees all Distributions. Notwithstanding the foregoing, if Pledgors receiveDistributions during the occurrence and the continuation of an Event of Default, Pledgorsshall hold the received Distributions as depositary of Pledgees and, upon Pledgees’ writtenrequest, Pledgors shall deliver those Distributions to Pledgees.Fifth. Covenants of Pledgors. So long as this Agreement is in effect, the Pledgors covenantand agree that they (a) shall defend the right, title and interest of Pledgees in and to thePledged Equity Interests against the claims and demands of any Person other than Pledgees; (b)shall not create, incur, assume, or permit to exist any Lien or security interest or option infavor of, or any claim of any Person with respect to, any of the Pledged Equity Interests, whethernow held or hereafter subscribed, except for the first priority security interest created herein;(c) shall not sell, transfer, assign, pledge, deliver, transfer in trust, grant, usufruct orotherwise dispose of, or grant any option with respect to, any such Pledged Equity Interests or anyinterest therein without the prior written consent of Pledgees; (d) shall execute and deliver toPledgees such documents in favor of Pledgees and do such things relating to the first prioritysecurity interest created herein as Pledgees may reasonably request in order to protect andmaintain the first priority security interest and to protect and preserve the Pledged EquityInterests, and pay all reasonable costs arising from or in connection therewith; (e) shall pay anyand all taxes, assessments, and other charges of any nature which may be imposed, levied, orassessed against or with respect to the Pledged Equity Interests or in connection with anyDistributions (other than taxes payable by Issuer in connection with such Distributions);and (f) shall cause Issuer to pay taxes payable by Issuer in connection with such Distributions.
 
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Sixth. Safekeeping of the Pledged Equity Interests. The obligations of Pledgees withrespect to the safekeeping and preservation of the Pledged Equity Interests shall be limited to theobligations imposed by law. Any actions carried out by Pledgees for the safekeeping andpreservation of the Pledged Equity Interests shall be at the sole expense and risk of the Pledgors,except for actions or omissions caused by the gross negligence, bad faith or willful misconduct ofPledgees.Seventh. Events of Default. If an Event of Default shall occur and be continuing (a) allrights of the Pledgors to exercise or refrain from exercising any voting and other rights whichthey would otherwise be entitled to exercise pursuant to Clause Fourth hereof shall cease and beexercised thereafter by Pledgees; (b) Pledgees shall have the right to keep any and allDistributions thereafter paid in respect of the Pledged Equity Interests and apply them to thepayment of the Secured Obligations; and (c) Pledgees are hereby expressly and irrevocablyauthorized by the Pledgors to foreclose upon the first priority security interest created hereinpursuant to the provisions of Clause Eighth of this Agreement, and to exercise its rights in anyother manner as set forth in the Law.Eighth. Foreclosure.(a) The Pledgors hereby expressly and irrevocably agree that upon the occurrence of an Event ofDefault, Pledgees may foreclose upon the first priority security interest created herein andrequest the sale of the Pledged Equity Interests, if any, pursuant to Article 341 of the Law,or exercise its rights in any other manner as set forth in the Law or this Agreement, in orderto seek payment of the Secured Obligations.(b) The Pledgors shall take or shall cause Issuer to take any and all reasonable actions and/orinitiate any and all reasonable proceedings that may be necessary or convenient, in thePledgees’ sole discretion, to facilitate the execution and transfer of the Pledged EquityInterests. The Pledgors further agree to do or cause to be done all such other reasonable actsas may be necessary or convenient to expedite such sale or sales of all or any portion of thePledged Equity Interests, and to execute and deliver such documents and take such other actionas Pledgees deem necessary or advisable in order that any such sale may be in compliance withapplicable law.(c) Due to the fact that the some Secured Obligations are monetary obligations denominated inDollars and payable outside of Mexico, in order to satisfy such Secured Obligations, any andall amounts in Pesos that are received by Pledgees will be (i) exchanged by Pledgees in aforeign exchange transaction into Dollarswith a financial institution appointed by Pledgees, and the currency so exchanged shall bedistributed by Pledgees pursuant to the RVOP Agreements; or (ii) in case such Pesos cannotbe exchanged into Dollars as a result of exchange rate controls or other governmentalaction, law or regulation, Pledgees will deliver such Pesos to the Lender pursuant to theprovisions of the RVOP Agreements.
 
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Ninth.- Assignments. Unless the RVOP Agreements provide otherwise, the rights andobligations arising from this Agreement may not be assigned or transferred by the Pledgors to anythird party without the prior written consent of Pledgees. Pledgees may assign, in whole or inpart, their rights hereunder, without requiring the consent of the Pledgors to perform suchassignment or transfer.Tenth.- Amendments. Unless the RVOP Agreements provide otherwise, this Agreement may onlybe amended or modified with the prior written consent of the Pledgors and Pledgees, subject to anyconsent required in accordance with the RVOP Agreements.Eleventh.- Notices. All notices to be delivered by the parties hereto shall be made inwriting in English (together with a Spanish translation), and shall be served either: (i)personally, return receipt requested; or (ii) by international recognized courier delivery, returnreceipt requested. All notices shall be served at the following addresses, and shall becomeeffective upon personal delivery:To RVOP:Rio Vista Operating Partnership, L.P.