Method for hydrogenating functionalized polymer and products thereof

Abstract

A method for preparing hydrogenated polymers containing acidic functionality in a portion thereof initially containing ethylenic unsaturation from a polymer containing ethylenic unsaturation or both aromatic and ethylenic unsaturation comprising the steps of first incorporating an acidic functional group precursor radical into the polymer, hydrogenating at least a portion of the ethylenic unsaturation contained in the polymer containing the acidic functional group precursor radicals and then converting at least a portion of the acidic functional group precursor radicals to the corresponding acidic functional group. In general, any acidic functional group precursor radical which will have less of an impact upon the hydrogenation reaction than the corresponding acidic functional group may be used. Best results are, however, achieved when acidic functional group precursors are used which are relatively neutral and which do not react or complex with the metal compounds used to prepare the catalyst or resulting from the combination of such metal compounds. The catalyst used to effect the hydrogenation will be prepared by combining a compound, preferably an alkoxide or carboxylate, of an iron group metal with an alkyl or a hydride containing a Group I-A, II-A or III-B metal. Preparation of the catalyst is preferably accomplished in the presence of water. Best results are achieved when the acidic functional group precursor is a metal salt and the metal salt and the reducing component used to prepare the catalyst contain the same metal. Depending upon the particular catalyst employed and the acidic functional group precursor radical used, up to about 90-95% of the ethylenic unsaturation initially contained in the polymer can be converted or hydrogenated.