This invention relates to a process for removing hydrogenation catalyst residue from hydrogenated polymers comprising:(I) treating a polymer cement comprising an unsaturated polymer in an inert water-immiscible liquid with a hydrogen source in the presence of a hydrogenation catalyst;(II
The invention provides a catalyst composition suitable for hydrogenation of polymers containing ethylenical unsaturation which comprises at least:(a) a titanium compound of the formula ##STR1## wherein A.sub.1 represents an optionally substituted heterocyclic five membered ring compr
