JP2792686B2 - Hydrogenation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hydrogenating polymers containing ethylenic unsaturation. More specifically, the present invention relates to a method for selectively hydrogenating ethylenic unsaturation contained in a polymer comprising ethylenic unsaturation and one or more cyano groups.

Polymers containing both ethylenic unsaturation and cyano groups are of course well known in the art. Such polymers are most often produced by copolymerizing polyolefins, especially diolefins, with ethylenically unsaturated nitriles, such as acrylonitrile. Such polymers can also include other monomers, such as those that introduce aromatic unsaturation into the polymer. Conjugated diolefins, especially polymers prepared by copolymerizing butadiene with ethylenically unsaturated nitriles, especially acrylonitrile, are of course well known in the prior art, and such polymers have been commercially produced for some time. . Although the most common use of such polymers is probably as synthetic rubber, such polymers are made in a fairly wide range of related compositions over a wide range of molecular weights, with a wide range of end uses. For example, such polymers are known to be useful in fibers, packaging, seals, tubes, membranes, sheaths, and the like. However, as is well known in the art, the low oxygen and ozone resistance and thermal stability of polymers do not generally allow the use of polymers alone in many of these end uses.

It is, of course, known in the art to selectively hydrogenate polymers to improve oxygen and ozone resistance and thermal stability by reducing the amount of ethylenic unsaturation contained therein. Previously, heterogeneous catalysts consisting of supported metals as taught in British Patent Nos. 2,011,911 and 2,087,403 were used. Various metals or metal compounds that can be used with or without support are taught in U.S. Pat. No. 3,700,637. However, these catalysts are not particularly active,
In addition, many of them are not particularly selective, so that ethylenic unsaturation cannot often be converted to a high degree without converting at least a part of the cyano group into an amine group.
Thereafter, mixed metal catalysts, in particular, for example, U.S. Pat.
Combinations of palladium with one or more other metals as taught in US Pat. No. 329 have been used,
These catalysts are also not particularly active, and many are not particularly selective. More recently, the use of metals supported on silica, such as platinum, palladium, ruthenium, etc., as taught by U.S. Pat. No. 4,452,951, has been proposed. When at least a portion of the cyano group is converted, the activity is relatively low, especially when Pd is used. More recently, the use of catalysts prepared by combining palladium carboxylate with a reducing agent such as hydrogen, as taught in U.S. Pat. Conversion of the group to an amino group often occurs. Also, this catalyst, especially those prepared using hydrogen as the reducing agent, is not particularly active. Even more recently, the use of various ruthenium compounds as taught by U.S. Pat.No. 4,631,315 has been proposed, including British Patent No. 1,558,491 and U.S. Pat.
The use of various rhodium complexes is also known, as taught by 00,637 and 4,647,627. While at least some of these latter catalysts promote particularly selective hydrogenation of such polymers, the catalytic metals are rather expensive or undersupplied. In view of these drawbacks, at least a metal which is reasonably available and can selectively hydrogenate polymers containing ethylenic unsaturation and one or more cyano groups, Obviously, there is a need for an improved catalyst composition that can convert (saturate) ethylenic unsaturation relatively efficiently while suppressing conversion.

It has now been found that the above-mentioned and other disadvantages of the conventional methods of hydrogenating polymers containing ethylenic unsaturation and cyano groups can be eliminated or at least reduced by the process according to the invention. Accordingly, it is an object of the present invention to provide a selective hydrogenation agent for polymers comprising both ethylenically unsaturated and cyano groups. Another object of the invention is to minimize the conversion of cyano groups to amine groups,
It is an object of the present invention to provide a process in which a substantial part of the ethylenic unsaturation results in converted (saturated) hydrogenated products. It is also an object of the present invention to provide such a process that uses a catalyst made from readily available or easily obtainable materials and a process that allows selective hydrogenation with relatively short contact times.

According to the present invention: (a) the presence of a catalyst prepared by combining one or more palladium compounds and one or more aluminum compounds in a second preferred solvent, which may be the same as or different from the first preferred solvent; Contacting a polymer comprising ethylenic unsaturation and cyano groups with hydrogen in a first suitable solvent; (b) a time sufficient to convert at least a portion of the ethylenic unsaturation contained in the polymer. Maintaining contact in step (a); and (C) recovering the at least partially hydrogenated polymer, selectively hydrogenating the polymer comprising ethylenically unsaturated and cyano groups, comprising the steps of: A method is provided.

In one embodiment of the present invention, the catalyst is prepared by contacting one or more aluminum compounds selected from the group consisting of aluminum hydride, alkylaluminum and mixtures thereof with one or more certain palladium compounds. The present invention, in another preferred form, produces a catalyst by contacting one or more palladium compounds with one or more alkyl alumoxane in a suitable solvent. For convenience, one or more alkylalumoxanes are often referred to herein simply as alumoxanes.

The catalyst is prepared by combining the palladium compound and the aluminum compound in a suitable solvent. Hydrogenation of the polymer is preferably carried out under high temperature and pressure, and
Performed in a suitable solvent.

The accompanying drawings are graphs showing the conversion or saturation of ethylenic unsaturation at two different nominal retention times as a function of the molar ratio of aluminum to palladium used in the preparation of the hydrogenation catalyst.

As described above, the present invention relates to a method for selectively hydrogenating ethylenic unsaturation and ethylenic unsaturation contained in a polymer comprising one or more cyano groups. Hydrogenation was carried out in the presence of a catalyst prepared by contacting one or more palladium compounds with one or more aluminum compounds in a suitable solvent.

In general, any polymer containing ethylenic unsaturation and one or more cyano groups may be hydrogenated in the process of the present invention. Hydrogenizable polymers include one or more polyolefins, especially diolefins, prepared by polymerization.
Addition polymers that also contain one or more cyano groups are included. Cyano groups can be introduced into the polymer by copolymerizing one or more ethylenically unsaturated nitriles with a polyolefin. It is also possible to introduce one or more ethylenically unsaturated nitriles into a polymer containing ethylenic unsaturation to introduce cyano groups. Also, a cyano group can be introduced by reacting a polymer containing ethylenic unsaturation with a compound capable of providing a cyano group to the polymer. For example, one or more cyano groups can be introduced into a metal atom containing polymer by reacting with Cl-C≡N as taught in US Pat. No. 3,135,716. The polymer that can be hydrogenated by the method of the present invention may have aromatic unsaturation. As is well known, aromatic unsaturation can be incorporated into polymers by copolymerizing monomers containing aromatic unsaturation, such as monoalkenyl aromatic hydrocarbons.

As is well known in the art, polymers composed of polyolefin monomer units and polymers composed of both polyolefin monomer units and monoalkenyl aromatic hydrocarbon monomer units are produced by polymerizing monomers in bulk, solution or emulsion. Can. Generally, any of the polymerization initiators or catalysts known in the art can be used to carry out the polymerization. Suitable catalysts include free radicals,
Mention may be made of anionic and cationic initiators or polymerization catalysts.
However, as is well known, anionic and cationic initiators cannot be used in emulsion polymerization.
Also, as is well known in the art, ethylenically unsaturated nitriles do not polymerize or copolymerize with anionic and cationic initiators. Thus, polymers made by copolymerizing one or more polyolefin monomers with one or more ethylenically unsaturated nitriles are most commonly made with free radical initiators or catalysts. Further, copolymers containing one or more ethylenically unsaturated nitrile monomer units are most often prepared by an emulsion process. When the polymer to be hydrogenated in the process of the invention contains one or more ethylenically unsaturated nitriles and is not a grafted or modified polymer but a copolymer prepared by direct copolymerization, a free radical initiator As above, the emulsion method is generally used. Such a polymer can be a random polymer, a tapered polymer or a block polymer. On the other hand, when the polymer to be hydrogenated is a graft or modified copolymer, the base polymer containing ethylenic unsaturation is first prepared by any known method and then the ethylenically unsaturated base is added thereto using a free radical initiator. Grafting a saturated nitrile or introducing a cyano group by a direct or indirect reaction between a polymer having ethylenic unsaturation or ethylenic and aromatic unsaturation and a compound capable of imparting a cyano group to the polymer be able to. Also in this case, if the base polymer is not a homopolymer, it may be a random polymer, a tapered polymer, or a block polymer.

Using the method of the present invention, any polymer containing ethylenic unsaturation and one or more cyano groups and optionally aromatic unsaturation can be selectively hydrogenated, however, the method of the present invention Copolymers of one or more conjugated diolefins and one or more ethylenically unsaturated nitriles; one or more monoalkenyl aromatic hydrocarbon monomers; one or more conjugated diolefins and one or more ethylenically unsaturated nitriles Copolymer; base polymer of one or more conjugated diolefins or 1
One or more montalkenyl aromatic hydrocarbon monomers and 1
A graft copolymer obtained by grafting one or more ethylenically unsaturated nitriles onto a base copolymer of one or more conjugated diolefins; a polymer of one or more conjugated diolefins and one or more monoalkenyl aromatic hydrocarbon monomers
It will most often be used to selectively hydrogenate modified polymers and copolymers modified by reacting a copolymer with one or more conjugated olefins with a compound capable of introducing a cyano group into the polymer. Each of these polymers may be prepared by methods well known in the art. Generally, the molecular weight and relative composition of the polymer to be hydrogenated in the method of the present invention are not particularly limited. However, it is important that the polymer be soluble in a suitable solvent for performing the hydrogenation, and this requirement will limit the maximum molecular weight of the useful polymer or its composition for a given solvent. .

In general, any of the palladium compounds known to be useful in making catalysts for hydrogenating ethylenic unsaturation can be used individually or in combination in making the catalysts of the present invention. And, as preferred compounds,
A palladium carboxylate of the formula (RCOO) _n Pd, wherein R is a hydrocarbyl group having 1 to about 50, preferably about 5 to about 20 carbon atoms, and n is a number satisfying the valency of Pd; A palladium chelate of about 3 to about 50, preferably about 3 to about 20, carbon atoms; Formula (RCO) _n Pd, wherein R is 1 to about 50 carbon atoms;
Preferably about 5 to about 30 hydrocarbon groups, where n is a number that satisfies the valency of Pd]; an alkoxide of the general formula Pd (SO
_x) salt of _n acid or its partial ester of the sulfur-containing; and the general formula Pd (R'SO _{3) n} [wherein, R 'is 1 to the number of carbon atoms
About 30 aliphatic or aromatic groups, and n is a number that satisfies the valency of Pd.] Palladium salts of aliphatic or aromatic sulfonic acids. Carboxylates useful for making the catalysts of the present invention include palladium salts of hydrocarbon aliphatic, hydrocarbon cycloaliphatic and aromatic hydrocarbon acids. Examples of hydrocarbon aliphatic acids are caproic acid (hexanoic acid), ethylhexanoic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid,
Stearic acid, oleic acid, linolenic acid, citronellic acid and the like can be mentioned. Hydrocarbon aromatic acids may include benzoic acid and alkyl-substituted aromatic acids wherein the alkyl substituent has 1 to about 20 carbon atoms. Examples of alicyclic acids are naphthenic acid, cyclohexylcarboxylic acid, abietic resin acids and the like. Suitable chelating agents that can be used in combination with various palladium compounds to prepare palladium chelates useful for the production of the catalyst of the present invention include β-ketone, α-hydroxycarboxylic acid, β-hydroxycarboxylic acid, β-hydroxycarboxylic acid,
And hydroxycarbonyl compounds. Examples of β-ketones that can be used include acetylacetone, 1,3-hexanedione, 3,5-nonadione, methyl acetoacetate, methyl acetoacetate and the like. Examples of α-hydroxycarboxylic acids that can be used include lactic acid, glycolic acid, and α-hydroxycarboxylic acid.
Hydroxyphenylacetic acid, α-hydroxy-α-phenylacetic acid, α-hydroxycyclohexylacetic acid and the like.
Examples of β-hydroxycarboxylic acids include salicylic acid,
Alkyl-substituted salicylic acid and the like can be mentioned. Β that can be used
Examples of the -hydroxycarbonyl compound include salicylaldehyde, o-hydroxyacetophenone and the like.
Metal alkoxides useful for preparing the catalyst of the present invention include palladium alkoxides of hydrocarbon aliphatic alcohols, hydrocarbon alicyclic alcohols and hydrocarbon aromatic alcohols. Examples of hydrocarbon aliphatic alcohols include hexanol, ethylhexanol, heptanol, octanol, nonanol, decanol, didecanol, and the like. Examples of palladium metal salts of sulfur-containing acids and partial esters thereof include palladium salts such as sulfonic acid, sulfuric acid, sulfurous acid, and partial esters thereof.
Among the salts of aliphatic and aromatic acids, salts of aromatic sulfonic acids such as benzenesulfonic acid, p-toluenesulfonic acid, and the like are particularly useful.

Generally, any one or more of the aluminum compounds known to be useful in making hydrogenation catalysts can be used to make the hydrogenation catalyst used in the process of the present invention. Suitable aluminum compounds include those having the general formula Al (R) ₃ , wherein each R can be the same or different groups selected from H and a hydrocarbyl group having 1 to about 20 carbon atoms. . Preferably, each R is an alkyl group having 1 to about 5 carbon atoms.

Another preferred group of suitable aluminum compounds are the alkylalumoxane compounds known to be useful in the production of olefin polymerization catalysts, as taught, for example, in U.S. Patent No. 4,665,208. Can be used individually or in combination for producing the hydrogenation catalyst of the present invention. The disclosures of the above patent specifications are incorporated herein by reference. Alumoxane compounds useful for the preparation of the catalyst of the present invention can be cyclic or linear. Cyclic alumoxanes general formula _{(R-Al-O) m} , linear alumoxanes have the general formula _{R 2 AlO- (R-Al-} O) - represented by _n AlR _2.
In both general formulas, each R and / or each R ₂ has 1 to 1 carbon atoms.
About 8, preferably 1 to about 5 identical or different alkyl groups such as methyl, ethyl, propyl, butyl and pentyl; m is an integer from about 3 to about 40; n is about 1 to about 40
Is an integer. In a preferred embodiment of the invention, the one or more alkylalumoxanes is a mixture of cyclic and linear alumoxanes, wherein each R is methyl;
m is a number from about 3 to about 20, and n is a number from about 10 to about 20. As is well known, alumoxanes can be produced by reacting an alkyl aluminum with water. Generally, the resulting product is a mixture of both linear and cyclic compounds.

As is well known, alkylalumoxane can be contacted with water in several ways. For example, the alkyl aluminum can be first dissolved in a suitable solvent, such as toluene or an aliphatic hydrocarbon, and then the solution can be contacted with a similar solvent having a relatively low water content. Alternatively, the alkyl aluminum can be contacted with a hydrated salt, such as hydrated copper sulfate or ferrous sulfate. When using this method, hydrated ferrous sulfate is often used. According to this method, a dilute solution of an alkyl aluminum in a suitable solvent such as toluene is contacted with hydrated ferrous sulfate. Generally, about 1 mole of hydrated ferrous sulfate is contacted with about 6 to about 7 moles of trialkylaluminum. When trimethylaluminum is used as the alkylaluminum, methane is generated when the conversion of the alkylaluminum to alumoxane occurs.

Generally, the hydrogenation catalyst useful in the hydrogenation process of the present invention is prepared by combining the palladium compound and the aluminum compound in a suitable solvent or diluent. Generally, the palladium compound and the aluminum compound are combined such that the Al: Pd ratio is about 0.1: 1 to about 1.5: 1, but the range of Al: Pd atomic ratio when using alumoxane is about 20. : 1 is preferred. Generally, under an inert or reducing atmosphere, about 20 to about 100
Contact at a temperature of ° C. Generally, any solvent or diluent that does not react with the palladium or aluminum compound used in preparing the catalyst may be used in preparing the catalyst. Of course, it is often most convenient to dissolve the polymer and produce the catalyst in the same solvent in which the subsequent hydrogenation takes place, and catalysts which can be used in the process of the invention using such solvents Suitable solvents for the polymer that can be hydrogenated by the method of the present invention, which can be used for the production of the polymer, are described below. However, catalysts made in ethereal solvents are significantly more active than catalysts made in hydrocarbons. Therefore, it is preferable to use an ether solvent for the production of the catalyst. In general, any linear or cyclic ether having 2 to about 20 carbon atoms and 1 to about 3 oxygen atoms may be used. Diethers having about 4 to about 10 carbon atoms are particularly effective and preferred. Generally, the palladium and aluminum compounds that can be used in the production of the hydrogenation catalyst can be, and preferably are, combined in separate vessels, but the temperature at which these components are contacted is within the ranges specified above. As far as possible, each component can be separately introduced into the hydrogenation reaction vessel. Generally, from about 1 to about 120 to reduce the palladium compound or other compound to produce an active catalyst.
Minute contact is sufficient.

Generally, the polymer in solution is hydrogenated. In general,
Any solvent conventionally known to be capable of use in dissolving a copolymer containing one or more conjugated diolefins, optionally one or more alkenyl aromatic hydrocarbons and one or more cyano groups, can be used. It can be used for hydrogenation in the inventive method. Thus, preferred solvents are linear and cyclic ethers such as diethyl ether, tetrahydrofuran and the like;
Halogenated, especially chlorinated aromatic hydrocarbons such as chlorobenzene, dichlorobenzene, methylchlorobenzene, etc .; acetone, methyl ethyl ketone, diethyl ketone,
Aliphatic and cyclic ketones such as butanone, pentanone, cyclopentanone, cyclohexanone and the like can be mentioned. Generally, a temperature of about 20 ° C to about 175 ° C, about 50 to about 1,0
Hydrogenation is performed at a total pressure of 00 psig and a hydrogen partial pressure of about 50 to about 950 psig. Generally, during the hydrogenation, a catalyst or catalyst component at a concentration sufficient to provide about 0.4 to about 40 mmol (gram molecule) of palladium per pound of polymer is added. Generally, contact under hydrogenation conditions is continued for a nominal retention time of about 10 to about 360 minutes. With regard to hydrogenation, the selective hydrogenation of ethylenically unsaturated is carried out under the above conditions, but when the degree of hydrogenation of ethylenically unsaturated reaches about 90%, conversion of cyano groups to amino groups is generally performed. It should be noted that In this regard, it should be noted that of the several variables that can be used to adjust the hydrogenation rate, temperature, catalyst concentration, and retention time generally have the greatest effect. Therefore, these variables can be carefully adjusted to prevent significant conversion of cyano groups to amine groups. Generally, hydrogenation of the aromatic unsaturation does not occur at the hydrogenation conditions intended for use in the process of the present invention. However, at higher conversions of ethylenic unsaturation, some aromatic unsaturation may also be converted.

While not wishing to be bound by any particular theory, it is believed that the palladium and aluminum compounds together cause a catalytic formation reaction. The catalyst thus formed is stable and can be stored for a relatively long time before use.

After the hydrogenation of the polymer is complete, the polymer may be recovered as a crumb using methods well known in the art. For example, the polymer can be recovered as debris by precipitation with a polar compound such as an alcohol. Alternatively, the solution can be brought into contact with steam or water and a solvent and subsequently removed by azeotropic distillation. Generally, these recovery methods also effectively remove a significant portion of the catalyst.

The hydrogenated polymer produced by the method of the present invention can be used for any of the applications which are conventionally well known in the art as the application of such a hydrogenated polymer. For example, selectively hydrogenated polymers consisting of one or more conjugated diolefin monomer units and cyano groups have improved weather and temperature resistance and can be used in seals, packaging, tubes, and the like.

In one preferred embodiment of the present invention, from about 55% by weight to
A random copolymer consisting of about 85% by weight of conjugated diolefin monomer units and about 45% to about 15% by weight of unsaturated nitrile monomer units may be prepared by dissolving, in solution, each alkyl group, which may be the same or different. A trialkylaluminum having from about 5 to about 5 carbon atoms and from about 5 to about 30 carbon atoms
Is selectively hydrogenated using a catalyst prepared by combining palladium carboxylate. Preferably, the butadiene / acrylonitrile copolymer is hydrogenated in the presence of a catalyst prepared by contacting palladium 2-ethylhexanoate with triethylaluminum. Preferably, the palladium carboxylate and trialkylaluminum are combined in an amount sufficient to provide an Al: Pd atomic ratio of about 0.3 to about 0.9. Preferably, the catalyst is prepared in a separate step using a diether having from about 4 to about 10 carbon atoms as a solvent. Preferably 1,
2-Dimethoxyethane is used as solvent.

In another preferred embodiment, from about 55% to about 85% by weight.
Wt% conjugated diolefin monomer units and about 45 wt%
A random copolymer comprising about 15 weight percent of unsaturated nitrile monomer units, in solution, the general formula (R-AlO) _m alumoxane least one general formula _{R 2 AlO- (R-AlO)} - n AlR 2 Wherein R is a methyl group, m is a number from about 3 to about 20, and n is from about 10 to about 20
And about 5 to about 30 carbon atoms of palladium carboxylate. Preferably, the butadiene / acrylonitrile copolymer is hydrogenated in the presence of a catalyst prepared by contacting palladium 2-ethylhexanoate with a preferred alkylalumoxane mixture. The mixture of palladium carboxylate and alkylalumoxane has an Al: Pd atomic ratio of about 0.2: 1 to
Preferably, sufficient amounts are combined to be about 10: 1. Preferably, the palladium carboxylate and alumoxane are combined in an amount sufficient to provide an Al: Pd atomic ratio of about 0.5: 1 to about 2: 1. The catalyst is preferably prepared in a separate step using ether as solvent. Most preferably, a diether having from about 4 to about 10 carbon atoms, such as 1,2-dimethoxyethane, is used as the solvent for preparing the catalyst.

In both of the preferred embodiments, the components used to make the catalyst are contacted at a temperature of about 25 ° C to about 60 ° C, and
Keep contact for a minute. About 20 ° C to about 100 ° C, about 50psig
Hydrogenation is suitably conducted at a total pressure of from about 1,000 psig and a hydrogen partial pressure of from about 50 to about 950 psig. It is preferred to carry out the hydrogenation in a ketone solvent, preferably an aliphatic ketone having from about 3 to about 10 carbon atoms, preferably a dialkyl ketone having from about 1 to about 5 carbon atoms in which the alkyls are the same or different, preferably ketones. Is methyl ethyl ketone.

It is preferred to carry out the selective hydrogenation such that at least about 85% of the ethylenic unsaturation originally contained in the polymer is converted (saturated) and only up to about 10% of the cyano groups are converted to amino groups. In a preferred embodiment, it is preferred that the polymer be present in solution at a concentration of about 2 to about 15% by weight of the combined polymer and solvent. Preferably, the nominal retention time under hydrogenated conditions is from about 30 to about 120 minutes. When using alumoxane, about 0.2 per pound of polymer
To about 15 mmol (gram molecule), preferably about 5 to about 15 mmol
Sufficient catalyst is added during the hydrogenation to yield (gram molecules) palladium.

Having thus described the invention and its preferred embodiments broadly, the invention will become more apparent by reference to the following examples. However, the examples are merely for explanation and are not intended to limit the present invention.

Example 1 In this example, a series of hydrogenation catalysts were prepared by combining a palladium salt of 2-ethylhexanoic acid and triethylaluminum at various Al: Pd atomic ratios. or,
For comparison, 2 without triethylaluminum
-Catalyst No. 1 below using palladium ethylhexanoate
A catalyst was manufactured. That is, the palladium salt of 2-ethylhexanoic acid was simply reduced with hydrogen in a hydrogenation reactor in the presence of a polymer to produce this catalyst. The Al: Pd atomic ratio of the catalyst produced in this example was 0 to about 1.5.
In the production of a catalyst using triethylaluminium as a reducing agent, a palladium salt and triethylaluminum are converted into 1,
Combine in 2-dimethoxyethane, contact at 25 ° C.,
The exotherm was left for 0 minutes. An aluminum-free catalyst was prepared by contacting the palladium salt with hydrogen in methyl ethyl ketone in the presence of a polymer at 60 ° C. and a hydrogen partial pressure of about 895 psig. In the production of each catalyst, the palladium salt concentration in the solvent was 40 mmol /. After preparation, each of the catalysts prepared with triethylaluminum was kept in a solvent and stored at 25 ° C until later used for selective hydrogenation of the modified block copolymer. In this example, a total of nine catalysts were produced. For convenience, these catalysts are referred to below as catalysts 1-9. Relative to that used to produce each of the nine catalysts
The atomic ratio of Al: Pd is summarized in Table 1 below.

Example 2 In this example, each catalyst prepared in Example 1 was used to selectively hydrogenate a butadiene-acrylonitrile rubber containing 80% by weight of butadiene and 20% by weight of acrylonitrile. Each hydrogenation was carried out at a total pressure of 900 psig at 60 ° C. and a partial pressure of hydrogen of about 895 psig in the presence of sufficient catalyst to provide about 8.5 mmol of Pd per pound of polymer.
Each hydrogenation was performed in methyl ethyl ketone solvent, and during each hydrogenation the polymer concentration was 5% by weight of the combined polymer and solvent. 30 minutes after each hydrogenation and 2
At time points, samples were removed and the degree of hydrogenation was measured for each of these samples. The relative amount of ethylenic unsaturation remaining in the polymer was measured by ozone titration to determine the degree of hydrogenation. The degree of hydrogenation at each catalyst after 30 minutes and 2 hours was plotted in the attached Figure 1. The results are shown in Table 2 below.

As can be seen from the data summarized in Table 2 and FIG. 1, the best results were obtained with catalysts prepared with an Al: Pd atomic ratio of about 0.3 to about 0.9. This is particularly evident from the curves in FIG. 1 with data obtained at a nominal retention time of 2 hours.

Example 3 In this example, a hydrogenation catalyst called catalyst No. 10 was produced by combining a palladium salt of 2-ethylhexanoic acid and methylalumoxane at an Al: Pd atomic ratio of 0.7: 1. Also, for comparison, the same palladium 2-ethylhexanoate and triethylalmonium as previously used at an Al: Pd atomic ratio of 0.7: 1 were combined to produce a catalyst designated as Catalyst No. 11. In the preparation of these catalysts, the ether or
Combine palladium 2-ethylhexanoate and aluminum compound in 1,2-dimethoxyethane and contact at 25 ° C.
The exotherm was left for 30 minutes. During the preparation of each catalyst, the concentration of palladium 2-ethylhexanoate in the solvent was 40 mmol /. After preparation, each prepared catalyst is kept in a solvent and stored at 25 ° C. until selective hydrogenation of the butadiene-acrylonitrile copolymer as summarized in Example 4.

Example 4 In this example, using the catalyst produced in Example 3,
A butadiene-acrylonitrile rubber containing 80% by weight butadiene and 20% by weight acrylonitrile was selectively hydrogenated. 60 ℃, total pressure 900psig and hydrogen partial pressure about 895p
Each hydrogenation was carried out in the presence of sufficient catalyst to provide sig, about 8.5 mmol Pd per pound of polymer. About hydrogenation was performed in a methyl ketone solvent, and the polymer concentration at each hydrogenation was 5 wt% of the combined polymer and solvent. During each hydrogenation, samples were taken after 30, 60, and 2 hours, and the degree of hydrogenation was measured for each of these samples. The degree of hydrogenation was determined by measuring the relative amount of ethylenic unsaturation remaining in the polymer using ozone titration. The degree of hydrogenation by each catalyst after 30 minutes, 60 minutes and 2 hours is shown in the attached Table 3.

As is clear from the data summarized in the previous table, catalyst No. 1
0 was more active than catalyst No. 11 for the entire time (2 hours) tested.

Example 5 In this example, two catalysts were produced as in Example 3, except that the amount of aluminum compound used was increased to an amount sufficient to provide an Al: Pd atomic ratio of 1.5: 1. The reactants and method used for catalyst preparation were the same as those summarized in Example 3. For convenience, the catalyst produced with alkylalumoxane is hereinafter referred to as catalyst No. 12, and the catalyst produced with triethylaluminum is referred to as catalyst No. 13. After preparation, the catalyst was kept in a solvent and stored at 25 ° C. until it was used to hydrogenate the same polymer as in Example 4 as summarized in Example 6 below.

Example 6 In this example, the catalyst produced in Example 5, ie, the catalyst
Using Nos. 12 and 13, the same polymer as that hydrogenated in Example 4 was hydrogenated. This example was performed under the same hydrogenation conditions as used in Example 4. 30 between each hydrogenation
A sample was taken out after 60 minutes, 120 minutes, and 120 minutes.
The degree of hydrogenation was measured in the same manner as used in. The results obtained in these experiments are summarized in Table 4 below.

As is clear from the data summarized in the preceding table, catalyst No. 12 which is a catalyst produced with alumoxane is particularly effective at this Al: Pd atomic ratio, but catalyst No. 13 which is a catalyst produced with triethylaluminum. Was considerably less active.

[Brief description of the drawings]

FIG. 1 is a graph plotting the conversion (or saturation) of ethylenic unsaturation at two different nominal retention times versus the molar ratio of aluminum to palladium used to produce the hydrogenation catalyst.

Continuation of the front page (72) Inventor Lynn Henry Throw United States, Texas 77429, Syprith, Rifleman Trail 12638 (56) References JP-A-61-247706 (JP, A) (58) Investigated Field (Int.Cl. ⁶ , DB name) C08F 8 / 00,8 / 04 B01J 21/00-21 / 20,23 / 44

Claims (23)

(57) [Claims] (A) one or more palladium compounds and one or more palladium compounds in a second solvent which may be the same as or different from the first solvent;
Contacting a polymer comprising ethylenic unsaturation and a cyano group with hydrogen in a first solvent in the presence of a catalyst prepared by combining one or more aluminum compounds; and (b) ethylene contained in said polymer. Maintaining the contact in step (a) for a time sufficient to hydrogenate at least a portion of the ethylenically unsaturated; and (c) recovering the at least partially hydrogenated polymer. A method for selectively hydrogenating ethylenic unsaturation of a polymer containing both saturation and cyano groups. 2. The method according to claim 1, wherein the first and second solvents are selected from the group consisting of linear or cyclic ethers, halogenated aromatic hydrocarbons and aliphatic or cyclic ketones. 3. A polymer comprising ethylenic unsaturation and cyano groups, the copolymer comprising one or more conjugated diolefins and one or more ethylenically unsaturated nitriles; one or more monoalkenyl aromatic hydrocarbon monomers; Copolymers of one or more conjugated diolefins and one or more ethylenically unsaturated nitriles; one or more base polymers of conjugated diolefins and one or more monoalkenyl aromatic hydrocarbon monomers and one or more conjugated diolefins A graft copolymer obtained by grafting one or more ethylenically unsaturated nitriles onto a base copolymer of the above; a modified copolymer of one or more conjugated diolefins modified by reacting a polymer or a derivative thereof with a compound capable of introducing a cyano group or 1 Modification of one or more monoalkenyl aromatic hydrocarbon monomers with one or more conjugated diolefins The method according to claim 1 or 2, wherein the method is selected from the group consisting of copolymers. 4. The process according to claim 1, wherein the contacting in step (a) is carried out at a temperature of 20 to 175 ° C., a total pressure of 50 to 1,000 psig and a hydrogen partial pressure of 50 to 950 psig. 5. The method according to claim 1, wherein the contacting in step (a) is continued for a holding time in the range from 10 to 360 minutes. 6. The method according to claim 1, wherein the one or more palladium compounds is a palladium carboxylate containing 1 to 50 carbon atoms. 7. A palladium carboxylate having 5 to 30 carbon atoms.
The method according to claim 6, wherein the number of the components is one. 8. The method according to claim 7, wherein the palladium carboxylate is palladium 2-ethylhexanoate. 9. An ether having 2 to 20 carbon atoms,
9. A method according to any of the preceding claims, wherein one or more palladium compounds and one or more aluminum compounds are combined. 10. The method according to claim 9, wherein the ether is a diether having 4 to 10 carbon atoms. 11. The method according to claim 10, wherein the ether is 1,2-dimethoxyethane. 12. The method according to claim 1, wherein the first solvent is a ketone having 3 to 10 carbon atoms. 13. The method according to claim 12, wherein the ketone is methyl ethyl ketone. 14. The method according to claim 1, wherein the hydrogenation is carried out so that the polymer saturates at least 85% of the ethylenic unsaturation originally contained, while the cyano groups which are converted into amine groups are less than 5%. 14. The method according to any of 13 above. 15. The process according to claim 1, wherein the one or more aluminum compounds are selected from aluminum hydride, alkyl aluminum and mixtures thereof. 16. A catalyst according to claim 15, wherein one or more palladium compounds and one or more aluminum compounds are contacted at an Al: Pd atomic ratio in the range of 0.1: 1 to 1.5: 1. The described method. 17. The method according to claim 16, wherein the atomic ratio of Al: Pd is in the range of 0.3: 1 to 0.9: 1. 18. The method according to claim 1, wherein the one or more aluminum compounds is one or more alkylalumoxanes. 19. A catalyst according to claim 18, wherein one or more palladium compounds and one or more alkylalumoxanes are contacted at an Al: Pd atomic ratio in the range of 0.2: 1 to 10: 1. The described method. 20. The method according to claim 19, wherein the atomic ratio of Al: Pd is 0.5: 1 to 2.0: 1. 21. One or more alkylalumoxanes are one or more alkylalumoxanes of the general formula (R—Al—O) _m and one or more alkylalumoxanes of the general formula R ₂ AlO— (R—Al—O) _n —AlR ₂ One or more alkylalumoxane wherein R and R ₂ are the same or different alkyl groups each having 1 to 5 carbon atoms, m is a number of 5 to 20, and n is a number of 10 to 20 21. The method according to claim 18, 19, or 20. 22. The method according to claim 21, wherein R is a methyl group. 23. The method according to claim 21, wherein R is an ethyl group.