Preparation of 1-octene by the selective tetramerization of ethylene

A diphosphinoamine ligands has been synthesized. In combination with Cr(III), methylalumoxane (MAO) and tetrachloroethane (TCE), they generate active catalytic systems for ethylene tetramerization toward 1-octene. The effects of reaction temperature, reaction pressure, molar ratio of Al/Cr, TCE/Cr, ligand/Cr, reaction time and sorts of cocatalyst on catalytic activity and selectivity to 1-octene were studied. The results show that the diphosphinoamine/Cr(III)/TCE/MAO four-membered catalytic systems for ethylene tetramerization have improved the selectivity to 1-octene, but catalytic activity is lower than that of three component system. MAO is requisite in forming active species for ethylene tetramerization toward 1-octene. TCE shows significant promotion effect to assist chromium center in improving selectivity toward 1-octene.

Graphical abstractThe effects of tetrachloroethane on the catalytic performance in ethylene tetramerization reactions were studied using a homogeneous [Cr(acac)3/diphoshinoamine(PNP)/methylaluminoxane (MAO)/tetrachloroethane] catalyst system. The results show that the tetrachloroethane has significant promotion effect to assist chromium center in improving selectivity toward 1-Octene. Figure optionsDownload full-size imageDownload as PowerPoint slide