Comparative dimerization of 1-butene with a variety of metal catalysts,and the investigation of a new catalyst for C-H bond activation

摘要

Catalytic dimerization of 1-butene by a variety of catalysts is carried out,and the products are analyzed by gas chromatography and mass spectrometry.Catalysts based on cobalt and iron can produce highly linear dimers,with the cobalt-based dimers exceeding 97% linearity.Catalysts based on vanadium and aluminum prefer to make branched dimers,which are most often methyl-heptenes in the case of vanadium and almost exclusively 2-ethyl-1-butene in the case of aluminum.The vanadium catalyst also produces substantial amounts of dienes and alkanes,suggesting a competing hydrogenation/dehydrogenation pathway that appears to involve vinyl C-H bond activation.Nickel catalysts are generally less selectin than those based on iron or cobalt for making linear dimers,but they can make dimers with 60% linearity.The major by-products for the nickel systems are trisubstituted internal olefins.An important side reaction that must be considered for dimerization reaction is 1-butene isomerization to 2-butene,which makes recycling the butene difficult for a linear dimerization process.Aluminum,iron,and vanadium systems promote very little isomerization,but nickel and cobalt systems tend to isomerize the undimerized substrate heavily.