Production of vinylidene olefins

摘要

Vinylidene olefin can be formed in good yield and high selectivity in much shorter reaction periods than found critical heretofore. The process involves dimerizing vinyl olefin with at least one trialkylaluminum compound as the catalyst component charged to the reaction vessel. These materials are charged to the reactor so that it contains in the range of 0.001 to 0.5 mol of trialkylaluminum per mol of the initial vinyl olefin. The reaction is performed at a temperature in the range of 100 DEG to 200 DEG C. for a period of time sufficient to convert 10 to 99% by weight of the initial vinyl olefin to a different product with at least 80 wt % vinylidene dimer selectivity. In conducting the process the liquid reaction mixture is in direct contact with a nickel-containing metal alloy surface for at least one hour at a temperature above about 50 DEG C., and (ii) at least one acetylenic hydrocarbon is added to the mixture prior to such contact in an mount at least sufficient to inhibit double bond isomerization in the reaction mixture but insufficient to inhibit formation of the vinylidene dimer. The acetylenic hydrocarbon also overcomes the devastating effect nickel impurities in the feed or in residues in the reactor have on dimer selectivity.