EFFECT OF CARBOXYLIC-ACIDS ON THE METATHESIS OF METHYL 10-UNDECENOATE

The metathesis of esters of unsaturated carboxylic acids catalyzed by the WCl//6/Me//4Sn system is influenced by the presence of free acids. The extent of their effect depends on how they are delivered into the reaction mixture. If the acid is allowed to react with WCl//6 (either free or as an admixture to the ester) before dosing Me//4Sn, the equivalent part of WCl//6 is converted rapidly to WOCl//4 and the activity of the catalyst is not affected. An excess of the acid over WCl//6, however, leads to carboxylation of WOCl//4 followed by the formation of WO//2Cl//2, and to loss of catalytic activity. Reaction of the acid with active centers already formed results in their deactivation.