Gel-free process for making hydrogenated functionalized anionically polymerized polymers

This invention relates to a gel-free process for making hydrogenated functionalized polymers that mitigates the problem of ionic gel. When multi-alkali metal initiators are used to make these polymers anionically, the process comprises anionically polymerizing at least one monomer with a multi-alkali metal initiator, usually a lithium alkyl, in a hydrocarbon solvent, capping the polymer by adding to the polymer a capping agent that reacts with the ends of the polymer chains such that strongly associating chain ends are formed wherein a strongly associating polymer gel is formed, adding a trialkyl aluminum compound to the polymer gel, whereby the gel dissipates, optionally terminating the polymerization by addition of an alcohol, washing the polymer with aqueous acid, preferably aqueous mineral acid, most preferably phosphoric acid, wherein there is at least one mole of phosphoric acid per mole of alkali metal and at least three moles of phosphoric acid per mole of aluminum, and hydrogenating the polymer with a hydrogenation catalyst. In a second embodiment, the present invention relates to a process for making such polymers which comprises anionically polymerizing them as described and adding a trialkyl aluminum compound prior to the addition of the functionalizing agent and washing the product prior to hydrogenation as described above. In the first embodiment, a gel is formed and then removed. In the second embodiment, the gel never is formed because of the presence of the trialkyl aluminum compound.

FIELD OF THE INVENTION
 This invention relates to a gel-free process for making functionalized
 polymers, primarily functionalized anionic polymers which are made using
 multi-lithium initiators. More particularly, this invention relates to a
 gel-free process for making polydiene diols.
 BACKGROUND OF THE INVENTION
 Functionalized anionically polymerized polymers of conjugated dienes and
 other monomers wherein the functionalization is terminal and/or internal
 are known. Particularly, U.S. Pat. No. 5,393,843 describes polybutadiene
 polymers having terminal functional groups. One of the methods described
 for making such polymers involves anionic polymerization utilizing a
 dilithium initiator such as the adduct derived from the reaction of
 m-diisopropenylbenzene with two equivalents of s-BuLi. Monomer is added to
 the initiator in hydrocarbon solution and anionic living polymer chains
 grow outwardly from the ends of the dilithium initiator. These polymers
 are then capped to form functional end groups as described in U.S. Pat.
 Nos. 4,417,029, 4,518,753, and 4,753,991. Of particular interest herein
 are terminal hydroxyl, carboxyl, sulfonate, and amine groups.
 It has been observed that when the living polymer is reacted with the
 commonly available "capping" agents, the polymer in the hydrocarbon
 solution forms a gel. For purposes of this invention, a polymer gel is
 defined as a blend of a polymer and a hydrocarbon solvent that has a yield
 stress, that is, it will not flow unless it is acted on by at least some
 critical stress. A polymer gel as defined herein will require a
 significant application of force in order to initiate flow through an
 orifice. Of particular interest are gels that will not flow under the
 force of their own weight. The presence of gel that will not flow under
 the force of its own weight is readily detected by visual observation.
 This effect is observed by inverting a bottle containing the solution to
 see whether it flows to the bottom of the inverted flask. Gelled solutions
 will not readily flow to the bottom of the bottle.
 The physical characteristics of these gels make them more difficult to
 handle in equipment which is designed for moving, mixing, or combining
 freely flowing liquids, i.e. materials without a significant yield stress.
 Pumps, reactors, heat exchangers, and other equipment that are normally
 used for making polymer solutions that can be characterized as viscous
 fluids are not typically suited to handling polymer gels. Thus, one would
 expect that processing equipment likely to be found at a manufacturing
 location that is designed to handle liquid polymer solutions, as defined
 above, would be ill suited to handling gels of this nature.
 If the living carbon-alkali metal endgroups (chain ends) are first
 transformed to the "ate" complex (aluminate) by reaction with a
 trialkylaluminum compound, the addition of EO occurs nearly
 quantitatively, without the formation of gel. Addition of a
 trialkylaluminum compound can also dissipate a gel of this kind that has
 already formed. The molar ratio of the trialkyl aluminum compound to the
 polymer chain ends is generally at least 0.1:1, preferably 0.33:1 and most
 preferably 0.66:1 to 1:1 since this results in a freely flowing solution.
 Unfortunately, at the preferred aluminum levels, the hydrogenation
 activity of the Ni/Al catalysts that are often used in the hydrogenation
 of these polymers is poor. Substantially more catalyst and longer reaction
 time are required to reach an acceptable level of residual unsaturation in
 the trialkylaluminum-containing cements than in controls prepared in the
 absence of aluminum. The present invention provides a method whereby
 polymers using trialkylaluminum to mitigate the gel problem can be
 efficiently hydrogenated.
 SUMMARY OF THE INVENTION
 This invention relates to a gel-free process for making functionalized
 polymers. When multi-alkali metal initiators are used to make these
 polymers anionically, the process comprises anionically polymerizing at
 least one monomer with a multi-alkali metal initiator in a hydrocarbon
 solvent, functionalizing the polymer by adding to the polymer a capping
 agent that reacts with the ends of the polymer chains such that strongly
 associating chain ends are formed leading to formation of a polymer gel,
 adding a trialkyl aluminum compound to the polymer gel whereby the gel
 dissipates, optionally terminating the polymerization by addition of an
 alcohol, washing the polymer, terminated or not, with an aqueous acid,
 preferably mineral acid, solution, and hydrogenating the polymer with a
 hydrogenation catalyst. The concentration of the acid solution and the
 aqueous phase ratio (ratio of aqueous acid to polymer solution) are chosen
 so as to insure solubility of the extracted alkali metal and aluminum
 salts. If phosphoric acid is used, it is preferable to add a sufficient
 amount such that there is at least one mole of acid per mole of alkali
 metal and at least three moles of acid per mole of aluminum.
 In a second embodiment, the present invention relates to a process for
 making such polymers which comprises anionically polymerizing them as
 described, adding to the polymer a trialkyl aluminum compound, and then
 adding the functionalizing reagent, optionally adding a terminating agent,
 and washing and hydrogenating the polymer as described above. In this
 second embodiment, the aluminum trialkyl may be added before or during
 polymerization or before or with the capping agent (i.e., before a gel can
 form-prior to any reaction of the alkali metal with the gel-forming
 functionality). In the first embodiment, a gel is formed and then removed.
 In the second embodiment, the gel never is formed because of the presence
 of the trialkyl aluminum compound.
 DETAILED DESCRIPTION OF THE INVENTION
 This invention relates to functionalized polymers and processes for
 avoiding gel formation, especially when such polymers are made by anionic
 polymerization using di- or multi-alkali metal, generally lithium,
 initiators. Sodium or potassium initiators can also be used. For instance,
 polymers which can be made according the present invention are those made
 from any anionically polymerizable monomer, especially including terminal
 and internal functionalized polydiene polymers, including random and block
 copolymers with styrene. Styrene copolymers hereunder can be made in the
 same manner as the polydiene polymers and can be random or block
 copolymers with dienes.
 In general, when solution anionic techniques are used, copolymers of
 conjugated diolefins, optionally with vinyl aromatic hydrocarbons, are
 prepared by contacting the monomer or monomers to be polymerized
 simultaneously or sequentially with an anionic polymerization initiator
 such as group IA metals, their alkyls, amides, silanolates, naphthalides,
 biphenyls or anthracenyl derivatives. It is preferred to use an organo
 alkali metal (such as lithium or sodium or potassium) compound in a
 suitable solvent at a temperature within the range from about -150.degree.
 C. to about 150.degree. C., preferably at a temperature within the range
 from about -70.degree. C. to about 100.degree. C. Particularly effective
 anionic polymerization initiators are organo lithium compounds having the
 general formula:
EQU RLi.sub.n
 wherein R is an aliphatic, cycloaliphatic, aromatic or alkyl-substituted
 aromatic hydrocarbon radical having from 1 to about 20 carbon atoms and n
 is an integer of 1 to 4. The organolithium initiators are preferred for
 polymerization at higher temperatures because of their increased stability
 at elevated temperatures.
 Functionalized polydiene polymers, especially terminally functionalized
 polybutadiene and polyisoprene polymers, optionally as copolymers, either
 random or block, with styrene, and their hydrogenated analogs are
 preferred for use herein. Especially preferred are polybutadiene diols.
 Such polymers are made as generally described above. One process for
 making these polymers is described in U.S. Pat. No. 5,393,843, which is
 herein incorporated by reference.
 Using a polydiene diol as an example, butadiene is anionically polymerized
 using a difunctional lithium initiator such as the sec-butyllithium adduct
 of diisopropenylbenzene as an example. The living chain ends are then
 capped with a capping agent such as described in U.S. Pat. Nos. 4,417,029,
 4,518,753, and 4,753,991, which are herein incorporated by reference.
 There are many multilithium initiators that can be used herein. The di-
 s-butyllithium adduct of m-diisopropenylbenzene is preferred because of
 the relatively low cost of the reagents involved and the relative ease of
 preparation. Diphenylethylene, styrene, butadiene, and isoprene will also
 work well to form dilithium initiators by the reaction:
 ##STR1##
 Still another compound which will form a diinitiator with an organo alkali
 metal such as lithium and will work herein is the adduct derived from the
 reaction of 1,3-bis(1-phenylethenyl)benzene (DDPE) with two equivalents of
 a lithium alkyl:
 ##STR2##
 Related adducts which are also known to give effective dilithium initiators
 are derived from the 1,4-isomer of DDPE. In a similar way, it is known to
 make analogs of the DDPE species having alkyl substituents on the aromatic
 rings to enhance solubility of the lithium adducts. Related families of
 products which also make good dilithium initiators are derived from
 bis[4-(1-phenylethenyl)phenyl]ether,
 4,4'-bis(1-phenylethenyl)-1,1'-biphenyl, and
 2,2'-bis[4-(1-phenylethenyl)phenyl]propane (See L. H. Tung and G. Y. S.
 Lo, Macromolecules, 1994, 27, 1680-1684 (1994) and U.S. Pat. Nos.
 4,172,100, 4,196,154, 4,182,818, and 4,196,153 which are herein
 incorporated by reference). Suitable lithium alkyls for making these
 dilithium initiators include the commercially available reagents (i.e.,
 sec-butyl and n-butyl lithium) as well as anionic prepolymers of these
 reagents, polystyryl lithium, polybutadienyl lithium, polyisoprenyl
 lithium, and the like.
 The polymerization is normally carried out at a temperature of 20 to
 80.degree. C. in a hydrocarbon solvent. The solution/dispersion/slurry of
 the polymer in the solvent is called the polymer cement. The cement
 usually has a solids (polymer) content in the range of 10 to 30 percent by
 weight (wt %) but it can range from 5 to 70 wt %. Suitable solvents
 include straight and branched chain hydrocarbons such as pentane, hexane,
 octane and the like, as well as alkyl-substituted derivatives thereof;
 cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane,
 cycloheptane and the like, as well as alkyl-substituted derivatives
 thereof; aromatic and alkyl-substituted derivatives thereof; aromatic and
 alkyl-substituted aromatic hydrocarbons such as benzene, naphthalene,
 toluene, xylene and the like; hydrogenated aromatic hydrocarbons such as
 tetralin, decalin and the like; linear and cyclic ethers such as dimethyl
 ether, methylethyl ether, diethyl ether, tetrahydrofuran and the like. The
 capping reaction is carried out in the same solution and usually at about
 the same temperature as the polymerization reaction, as a matter of
 convenience.
 The general class of capping agents useful herein which form strongly
 associating chain ends and cause gelation are those which form alkali
 metal-O or alkali metal-N (preferably, LiO and LiN) bonds. Specific
 capping agents which are highly useful herein include ethylene oxide and
 substituted ethylene oxide compounds, oxetane and substituted oxetane
 compounds, aldehydes, ketones, esters, anhydrides, carbon dioxide, sulfur
 trioxide, aminating agents which form lithium imides, especially imines,
 and suitable reactive amine compounds like 1,5-diazabicyclohexane as
 described in U.S. Pat. No. 4,816,520 which is herein incorporated by
 reference. At least 0.1 mole of capping agent per mole of polymer chain
 end is necessary to give sufficient functionalization for most
 applications. It is preferred that from 1 to 10 moles of the capping agent
 per mole of polymer chain end be used in the capping of the polymer
 although the upper limit is only a practical one determined by cost
 benefit.
 At this point in the process, the polymer forms a gel. A trialkyl aluminum
 compound is then added to this gel which then dissipates. The alternative
 process involves adding the trialkyl aluminum compound to the polymer
 mixture before the alkali metal reacts with the gel-forming functionality
 to form a gel. It may be added before, during, or after polymerization. In
 these cases, no polymer gel forms. If the trialkyl aluminum is added
 before or during polymerization, then less than a molar ratio of Al:Li of
 1:1 should be added because the polymerization will stop if the ratio
 reaches 1:1. In yet another alternative, the trialkyl aluminum compound is
 added at the same time as the capping reagent. It may be premixed with the
 capping agent or just added to the reactor at the same time as the capping
 reagent. In this process, no polymer gel forms. Using triethyl aluminum as
 an example, it is believed that the mechanism of these two processes,
 adding the trialkyl aluminum reagent either before or after capping, is as
 follows:
 ##STR3##
 As described above, gel is avoided or removed by addition of a trialkyl
 aluminum compound. It is important that the chain end retains activity for
 nucleophilic substitution reactions after the "ate" complex has formed.
 Even after the trialkyl aluminum reagent has been added and the "ate"
 complex has formed, the chain end is still capable of further reaction.
 The trialkyl aluminum compounds used in the present invention are those
 wherein the alkyl groups contain from 1 to 10 carbon atoms. Preferred
 trialkyl aluminum compounds are triethyl aluminum, trimethyl aluminum,
 tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum,
 tri-n-hexylaluminum, and trioctyl aluminum because these reagents are
 readily available in commercial quantities. Triethylaluminum is most
 preferred as it is least expensive on a molar basis.
 The molar ratio of the trialkyl aluminum compound to the polymer chain ends
 is generally at least 0.1:1, preferably 0.33:1 and most preferably 0.66:1
 to 1:1 since this results in a freely flowing solution. If it is less than
 0.1:1, then the level of reduction in gel is too low to give an observable
 reduction in either the shear stress or the viscosity of the solution. If
 the ratio is more that 1:1, then the cost goes up unnecessarily but the
 advantages are still achieved. It is advantageous to be able to use less
 aluminum for cost purposes.
 This invention also facilitates hydrogenation in situations wherein a
 trialkylaluminum compound is used in the functionalization of an existing
 polymer or the conversion of the functionality of an already
 functionalized polymer to a different functional group using one of the
 gel-forming capping agents described herein.
 Following functionalization, it is common practice to terminate the
 reaction by the addition of an alkanol, preferably methanol. It is
 preferable to add a sufficient quantity of the terminating alcohol to
 provide one mole of the alcohol per mole of alkali metal, usually lithium,
 and three moles of the alcohol per mole of aluminum. Reaction with the
 alcohol results in alcoholysis of the alkylaluminum. In the case of
 triethylaluminum, this is expected to result in a mixture of
 dialkoxyethylaluminum and trialkoxyaluminum, with the displaced ethyl
 groups having been converted into ethane. When terminal alcohol groups are
 introduced, for example, by reaction with ethylene oxide, addition of the
 alcohol also results in an equilibrium level of protonation of the polymer
 chain ends. Methanol is preferred in this case as the resulting
 equilibrium favors protonation of chain ends. If a less acidic alcohol,
 such as 2-ethylhexanol, is used, the polymer cement may exhibit the
 properties of a weak gel. Presumably, this is due to interaction of
 ionized chain ends with the alkoxy(alkyl)aluminum products. This step may
 be omitted. However, partial hydrolysis of the terminal "ate" complex
 leads to Al--O--Al bonds. In the absence of vigorous mixing, this can
 result in the temporary formation of a rather strong gel during the wash
 process. Also, this hydrolysis liberates substantial quantities of ethane
 gas, leading to problems with foaming. Hydrolysis of the alcohol reaction
 products is slower, leading to less problems with gel formation in wash,
 and does not liberate ethane as vigorously. For these reasons, it is
 generally desirable to terminate the polymerization with an alkanol after
 functionalization.
 The polymer solution is then washed with aqueous acid. Mineral acids
 (phosphoric, sulfuric, hydrochloric acids, etc.) are generally preferable,
 as these acids are inexpensive, readily available, and have little
 tendency to partition into the organic phase. Acids that partition into
 the organic phase may interfere with hydrogenation. The quantity and
 strength of the acid used are chosen so that the salts that are produced
 are soluble. If phosphoric acid is used, it is preferable to add a
 sufficient quantity to supply 1 mole of acid per mole of lithium and at
 least 3 moles of acid per mole of Al. It is also preferable to use a
 relatively concentrated acid solution at a relatively low aqueous acid
 phase weight ratio. For a 20% solids content in the cement wherein the
 polymerization targets a molecular weight of about 4,000, it is most
 preferable to conduct the wash using 20% wt. to 40% wt. aqueous phosphoric
 acid at a aqueous acid phase weight ratio between about 0.1:1 and 0.25:1
 aqueous acid:cement and at a temperature of about 45.degree. C. to
 55.degree. C. Although this extraction is relatively insensitive to mixing
 conditions, it is preferable to avoid unnecessarily high shear. The cement
 should be allowed to settle until substantially free of entrained water.
 The wash can be performed under conditions of minimal dispersion ("dancing
 interface") contact, which results in very little entrainment of the
 aqueous acid in the organic phase, or by more vigorous mixing, followed by
 settling. The water concentration by Karl Fisher titration should then be
 on the order of 400 ppm. Surprisingly, the efficiency of hydrogenation of
 these cements with the standard Ni/Al catalyst was found to comparable to
 dry, aluminum-free solutions of comparable polymers. The Ni/Al catalyst
 can then be extracted into aqueous acid and the liquid polymer product
 isolated by devolatization.
 Hydrogenation of polymers of conjugated dienes is typically accomplished
 with the use of nickel catalysts, as described in U.S. Pat. Nos. Re.
 27,145 and 4,970,254 and U.S. patent application Ser. No. 07/785715, now
 U.S. Pat. No. 5,166,277 which are incorporated herein by reference. The
 preferred nickel catalyst is a mixture of nickel 2-ethylhexanoate and
 triethylaluminum. Hydrogenation may also be accomplished using the
 catalysts described in U.S. Pat. Nos. 3,415,759 and 5,057,582, which are
 herein incorporated by reference. These catalysts are made by contacting
 one or more Group VIII metal carboxylates (CAS version, Group VIIIA in the
 previous IU form, and Groups VIII, IX and X in the new notation) with
 one or more alkyl alumoxanes which were prepared by reaction of an
 aluminum alkyl with water. As described in the above patents, such
 catalysts produce excellent results in that they selectively hydrogenate
 ethylenic unsaturation to a high degree while basically unaffecting the
 aromatic unsaturation. The preferred Group VIII metals are nickel and
 cobalt. Other homogeneous hydrogenation catalysts can be used including
 those made with Ti, Ru, Rh, etc. Heterogeneous hydrogenation catalysts can
 also be used including those made with Pt, Pd, Ni, Co, etc.

EXAMPLES
 Diol Synthesis Reactions
 Synthesis conditions and characterization are described in Table 1. Unless
 otherwise specified, the initiators were prepared by adding two moles of
 either s-butyllithium or t-butyllithium to one mole of
 m-diisopropenylbenzene in cyclohexane in the presence of one mole of
 diethylether (DEE) per mole of lithium at a temperature of 20.degree. C.
 to 50.degree. C. These initiators were used to polymerize butadiene in
 cyclohexane/10% wt. DEE in a 2 liter glass autoclave, targeting a
 butadiene number average molecular weight of 4,000 or 3,200. The initiator
 fragment and EO endcaps add another 530. In general, molecular weights
 were close to predicted (basis titration of the initiator) and
 polydispersities were relatively low, &lt;1.2. Polymer solids in the cements
 were varied from 10% wt. to 20% wt. At greater than 10% solids, the
 monomer was added in several increments. An attempt was made to keep the
 polymerization temperature below 50.degree. C. Vinyl contents in excess of
 50% could be achieved if the average polymerization temperature was kept
 at or below about 25.degree. C. Triethylaluminum (TEA) was used to break
 up, or prevent gel and ethylene oxide (EO) was reacted with the living
 chain ends in order to introduce the desired hydroxyl endgroups. Unless
 otherwise specified, one mole of TEA was added per mole of chain ends.
 Ethylene oxide was generally added in an amount of at least 20%.
 The capping reaction was carried out according to one of the following
 procedures: (1) A bomb containing (EO) was connected to the reactor and a
 bomb containing an approximately 16% wt. solution of triethylaluminum in
 hexane was attached to it. The valves of the sample bombs were then opened
 sequentially, starting at the valve closest to the reactor, so that the EO
 was added, followed very rapidly by the alkyl aluminum solution. Reaction
 with EO is very fast, so gel was observed to form. This gel broke very
 rapidly, yielding a pale yellow, freely flowing, low viscosity solution.
 (2) Two bombs, one containing the desired quantity of EO and the other
 containing the desired quantity of an approximately 16% wt. solution of
 triethylaluminum (TEA) in hexane, were attached to the reactor as
 described above. When the polymerization was complete, the TEA solution
 was pressured into the bomb containing the EO and allowed to interact for
 about one minute. The contents were then pressured into the autoclave and
 allowed to react with the living chain ends for 30 minutes. While the heat
 of mixing of the EO and TEA was appreciable, .sup.1 H NMR of the mixture
 suggested that the reaction between EO and TEA was relatively slow under
 these conditions. No increase in viscosity was observed on addition of the
 mixture and the color faded to pale yellow, indicative of capping. (3) The
 desired quantity of about 16% to 25% wt. triethylaluminum solution was
 added and allowed to react with the living chain ends for 15 minutes. The
 reaction was exothermic enough to raise the temperature a few degrees. The
 yellow color of the polymer anion persisted, but the solution viscosity
 decreased noticeably, especially at higher polymerization solids. After 15
 minutes, the EO charge was added and flushed in with about 44 grams of
 cyclohexane from a bomb attached above it, resulting in a temperature
 increase of a few degrees and a decrease in the color of the solution, but
 no increase in the viscosity. One polymerization, run 22930-83C, was
 performed at 0.5:1 TEA:Li. The resulting solution was higher in viscosity,
 but much less so than is obtained in the absence of TEA. Unless otherwise
 specified, methanol was then added to "terminate" the polymerization.
 Sufficient methanol was added to provide 1 mole of methanol per mole of
 lithium and about 3.1 moles of methanol per mole of aluminum. For
 comparison, a polymerization was conducted at 10% solids, EO was added,
 and the resulting gel was allowed to stand until the color of the entire
 reactor contents changed from the red-orange of the polymer anion to the
 pale yellow of the EO-capped diol. An excess of methanol was added to
 break the gel.
 TABLE I
 Synthesis Conditions for Preparation of Diinitiated Butadiene Polymers and
 Capping with EO.
 Polymerization Capping Reaction
 Mn Addition
 Sample # RLi [DiLi] (N) % Solids (.sup.1 H NMR) Order TEA:Li
 t.sub.rxn (min).sup.1 EO/Li
 22930-82D s-BuLi 0.47 10% 3700 -- None
 overnight 1.3
 22930-83C s-BuLi 0.47 10% 3700 EO 1st. 1:1 30
 1.2
 22930-84B s-BuLi 0.47 10% 3790 EO 1st. 1:1 30
 1.2
 22930-90A s-BuLi 0.38 10% 3950 Al to EO 1:1 1
 2.3
 22930-104C t-BuLi 0.57 20% 5290 Al 1st 1:1 15
 2.4
 22930-105B t-BuLi 0.57 20% 4970 Al 1st 1:1 15
 3.2
 22930-107B t-BuLi 0.5 20% 4470 Al 1st 1:1 15
 2.4
 22930-109B s-BuLi 0.57 10% 4360 Al 1st 1:1 15
 1.5
 .sup.1 Case (1): time EO/TEA mixture is in contact with PLi prior to
 termination; Case (2): time EO in contact with TEA prior to addition to
 PLi; Case (3): time TEA in contact with PLi prior to EO addition.
 Hydrogenation
 Unless otherwise specified, hydrogenation reactions were carried out in a 1
 gal. SS autoclave using a Ni/Al catalyst prepared by reacting
 triethylaluminum and nickel octoate (2:1 Al:Ni), according to the
 following general procedure. The polymer cement was charged to the
 autoclave and sparged with argon (if the transfer was not conducted under
 nitrogen), and then with hydrogen. Only cements that had been washed were
 exposed to ambient atmosphere. The reactor was pressured up to 800 psi
 with hydrogen. The reactor temperature was adjusted to about 60.degree. C.
 and then the first aliquot of catalyst solution was added. The autoclave
 was then heated to maintain a temperature of about 80.degree. C. and
 reaction was allowed to proceed under 800 psi of H.sub.2 for the desired
 time. Additional aliquots of catalyst were added as specified in Table 2
 below. The catalyst was extracted with aqueous phosphoric acid (generally
 20% wt). The extent of hydrogenation was determined using 1H NMR. These
 results are summarized in Table 2. Samples for further testing were washed
 with deionized water until the pH of the settled aqueous phase was &lt;5 and
 then dried in a rotary evaporator.
 A number of attempts were made to hydrogenate the alcohol terminated
 polymer solutions. Methanol-terminated cements prepared at a TEA:Li ratio
 of 1:1 remained poorly hydrogenated after quite long reaction times at
 high catalyst loadings, as evidenced by runs 22930-84C and 22930-90B. When
 2-ethylhexanol (2-EH) was substituted for methanol, the cement gelled on
 standing. It was necessary to add methanol to break the gel before the
 solution could be hydrogenated. Not surprisingly, hydrogenation was quite
 difficult. Hydrogenation of the cement prepared using an 0.5:1 ratio of
 TEA to Li was more facile, but still rather difficult. After reaction with
 a total of 225 PPM Ni for a total reaction time of greater than 18 hours,
 0.34 meq/g of residual unsaturation remained (98.0% conversion). The
 reactor was blocked-in at 800 psi hydrogen overnight at ambient
 temperature after a total of 125 PPM Ni had been added. By comparison, the
 cement prepared at 10% solids without adding TEA was hydrogenated to a
 residual unsaturation of 0.18 meq/g (98.9% conversion) in 2 hours in the
 presence of only 125 PPM Ni.
 The solution provided herein is to wash the aluminum and lithium out with
 aqueous acid prior to hydrogenation. It is unexpected that this would work
 well since the Ni/Al catalyst is known to be susceptible to deactivation
 by relatively low levels of water. For this reason, extraction with
 aqueous acid would not be anticipated to lead to improved hydrogenation
 performance unless followed by some operation to remove residual water.
 The catalyst was extracted using aqueous phosphoric acid. In all cases,
 sufficient H.sub.3 PO.sub.4 was added to provide 1 mole of acid per mole
 of lithium, and 3 moles of acid per mole of aluminum. At this ratio the
 aluminum phosphate salts were observed to remain soluble in the aqueous
 phase. Use of phosphoric acid at concentrations of 20% wt. to 40% wt.
 allows for aqueous acid phase weight ratios (aqueous:organic) in the range
 of 0.1:1 to 0.25:1. Unless otherwise specified, these extractions were
 performed in a glass resin kettle (with indents to act as baffles) at
 about 50.degree. C. to 60.degree. C.
 The first pre-hydrogenation wash was carried out under minimally dispersive
 or "dancing interface" conditions, that is, the stir rate was set just
 below the point at which droplets of one phase began to break off and
 disperse into the other phase. Samples of the cement were collected and
 analyzed for water, aluminum, lithium, and phosphate during the
 extraction. This data is summarized in Table 3. The initially clear cement
 began to turn cloudy and increase in viscosity until a very weak gel
 formed. As the extraction continued, the cement near the interface began
 to clear and decrease in viscosity. After an hour, the entire cement phase
 was once again clear and low in viscosity. These observations suggest the
 following sequence of events. Initially, little metal extraction occurs
 but water begins to diffuse into the cement and reacts with aluminum to
 produce a weak gel. As the extraction proceeds, the aluminum and lithium
 are pulled into the aqueous phase until finally the cement is
 substantially free of metals. Indeed, a cement sample taken at 20 minutes
 was very high in Al and Li, while the 60 minute sample contained only
 about 45 ppm Al and 7 ppm Li. As expected, the water and phosphate levels
 were low, 450 ppm and 10 ppm, respectively. Little change occurred on
 settling for 1 hour. This cement (105B) was then hydrogenated with no
 further treatment. As can be seen front Table 3 hydrogenation was quite
 facile. The residual unsaturation was decreased to 0.27 meq/g after
 reaction for 2 hours in the presence of 150 ppm Ni. Addition of another
 100 PPM of Ni reduced the value to 0.08 meq/g (over 99.5% conversion).
 In a second experiment, the wash was carried out in a more conventional
 way. The cement and aqueous acid were mixed at a high enough stir rate to
 disperse the acid in the organic phase. After 20 minutes, stirring was
 discontinued and samples were taken at 15, 30 and 60 minutes. The low
 lithium and phosphate levels, even after less than an hour of settling,
 suggest that extraction is efficient and little of the aqueous acid
 remains entrained after a reasonable settling time. Contact with deionized
 water resulted in no further decrease in the level of ionic species. After
 settling overnight, the water, lithium and aluminum were down to 330 ppm,
 2 ppm, and &lt;10 ppm, respectively. This sample (107B) was also hydrogenated
 without difficulty, reaching an residual unsaturation of 0.1 meq/g in 3
 hours with only 85 ppm of Ni.
 The cements in the above examples were terminated with methanol. Contact
 with water should also effectively terminate the living chain ends. Since
 all of the aluminum and lithium are extracted in the wash, the
 hydrogenation should not be effected by how the polymerization is
 terminated.
 In a third experiment, the "live" polymer cement was added directly to the
 aqueous acid. Under the mixing conditions of this experiment, a gel formed
 as the cement was added. The gel formed faster, and was stronger, than was
 observed in the "minimally-dispersive mixing" experiment. Foaming also
 occurred, presumably due to out-gassing of ethane. When cements were
 terminated with methanol, ethane evolution was slower. A significant
 fraction of the ethane produced by reaction with the alcohol was probably
 lost when the polymerization reactor was vented. The stir rate was
 increased to about 400 RPM to facilitate dissolution of the gel.
 Extraction and de-entrainment was less effective in this case. The final
 cement contained 780 ppm water, 57 ppm phosphate, 26 ppm Li, and 460 ppm
 Al. Nevertheless, the hydrogenation was accomplished without difficulty.
 An residual unsaturation of 0.22 meq/g was achieved after adding only 80
 ppm Ni.
 TABLE 2
 Hydrogenation Results for Alcohol - Terminated and Washed Cements
 (no pre-hydrogenation extraction)
 Wash Conditions Second
 Catalyst Charge 3rd Catalyst Charge
 Phase Ratio 1st Catalyst Charge
 added added
 (Aq.: PPM T.sub.max time RU PPM
 at time time RU PPM at time RU
 Run Feed [H.sub.3 PO.sub.4 ] Organic) RPM Ni (.degree. C.) (min)
 (meq/g) Ni (min) (min) (meq/g) Ni (min) time (meq/g)
 83A 82D -- -- -- 25 86 60 1.79 125
 60 120 0.18 -- -- -- --
 84A 83C.sup.c -- -- -- 25 83 60 1.96
 125 60 120 0.81 225 t.sup.a t + 60 0.34
 84C 84B -- -- -- 25 78 60 4.86 125
 60 120 2.86 225 120 180 2.2
 90B 90A -- -- -- 50 64 60 9.26 150
 60 120 3.01 250 120 180 1.76
 104D 104C.sup.b -- -- -- 100 94 60 6.27
 200 60 120 4.5 300 120 225 3.5
 106A 105B 40% 0.11 200 50 &gt;100 60 2.13 150
 60 120 0.27 250 120 250 0.08
 107C 107B 20% 0.21 400 10 103.sup.d 30 15.35
 35 30 90 0.49 85 90 180 0.1
 110A 109B.sup.e 20% 0.21 400 20 90.sup.d 60
 5.01 80 60 120 0.22 -- -- -- --
 .sup.a sat in autoclave at room temp under H.sub.2 overnight, brought to
 temp & last 100 PPM added next day.
 .sup.b Initially terminated with 2-ethylhexanol; gelled, added methanol to
 break.
 .sup.c 0.5:1 TEA:Li.
 .sup.d occurred after 2nd catalyst charge.
 .sup.e cement washed without MeOH termination.
 TABLE 2
 Hydrogenation Results for Alcohol - Terminated and Washed Cements
 (no pre-hydrogenation extraction)
 Wash Conditions Second
 Catalyst Charge 3rd Catalyst Charge
 Phase Ratio 1st Catalyst Charge
 added added
 (Aq.: PPM T.sub.max time RU PPM
 at time time RU PPM at time RU
 Run Feed [H.sub.3 PO.sub.4 ] Organic) RPM Ni (.degree. C.) (min)
 (meq/g) Ni (min) (min) (meq/g) Ni (min) time (meq/g)
 83A 82D -- -- -- 25 86 60 1.79 125
 60 120 0.18 -- -- -- --
 84A 83C.sup.c -- -- -- 25 83 60 1.96
 125 60 120 0.81 225 t.sup.a t + 60 0.34
 84C 84B -- -- -- 25 78 60 4.86 125
 60 120 2.86 225 120 180 2.2
 90B 90A -- -- -- 50 64 60 9.26 150
 60 120 3.01 250 120 180 1.76
 104D 104C.sup.b -- -- -- 100 94 60 6.27
 200 60 120 4.5 300 120 225 3.5
 106A 105B 40% 0.11 200 50 &gt;100 60 2.13 150
 60 120 0.27 250 120 250 0.08
 107C 107B 20% 0.21 400 10 103.sup.d 30 15.35
 35 30 90 0.49 85 90 180 0.1
 110A 109B.sup.e 20% 0.21 400 20 90.sup.d 60
 5.01 80 60 120 0.22 -- -- -- --
 .sup.a sat in autoclave at room temp under H.sub.2 overnight, brought to
 temp & last 100 PPM added next day.
 .sup.b Initially terminated with 2-ethylhexanol; gelled, added methanol to
 break.
 .sup.c 0.5:1 TEA:Li.
 .sup.d occurred after 2nd catalyst charge.
 .sup.e cement washed without MeOH termination.