Olefin disproportionation process

A process for the disproportionation of olefins comprising contacting at least two suitable non-conjugated olefinic reactants under suitable reaction conditions with a catalytic amount of a catalyst composition consisting essentially of (1) at least one neutral carbene complex having the general formula ##STR17## wherein R is an aryl or substituted aryl radical containing 6 to 30 carbon atoms per radical wherein the substituted aryl radical can have one or more substituents each of which can be the same or different and selected from the group consisting of halides, alkoxides and alkyl radicals containing 1 to 20 carbon atoms per radical;

• R.sup.I is selected from the group consisting of alkyl, cycloalkyl, aryl, substituted aryl, trialkylsilyl, and triarylsilyl radicals containing 1 to 30 carbon atoms per radical with the aryl substituents being the same as for the sustituted aryl of R;
• Y is 0, Se, S, N, or P;
• m is 1 when Y is 0, Se, or S and 2 when Y is N or P;
• M is tungsten or rhenium;
• each L is individually selected from CO, NO, PF.sub.3, PCl.sub.3, or pyridine;
• L.sup.I is cyclopentadienyl or allyl;
• p is 0 or 1;
• and n is 5 when p is 0 or 2 when p is 1, and
• (2) at least one activator selcted from chlorinated or chlorobrominated saturated organic compound having 1 to 20 carbon atoms per molecule and containing only carbon and chlorine or carbon, chlorine, and bromine.