Titanium Complexes with Functional Alkoxido Ligands for Selective Ethylene Dimerization – A High Throughput Experimentation Approach

Abstract New titanium complexes of general formula [Ti(OR) 2 (O i Pr) 2 ], containing functionalized alkoxido ligands, were developed for the selective catalytic dimerization of ethylene to 1‐butene using a combined High Throughput Screening (HTS) / Design of Experiment (DoE) approach. First, a library of 19 ligands was elaborated and a primary screening spotted the phosphorus‐functionalized alkoxido ligands as most promising. A second, more focused library containing 8 alkoxidophosphane ligands was then developed. A longer linear spacer between the alkoxido and the phosphorus functions, as in [Ti( 19 ) 2 (O i Pr) 2 ], was found beneficial for this catalytic reaction. After identification of the best co‐catalyst (AlEt 3 ) and co‐ligand (O n Bu), final optimization of the reaction conditions was performed using a design of experiments (DoE) approach. The complex [Ti( 19 ) 2 (O n Bu) 2 ] was shown to selectively dimerize ethylene in 1‐butene (C 4 (α)=93 % (99 + %)) at 30 bar C 2 H 4 and 55 °C with AlEt 3 as co‐catalyst, resulting in very high activity and selectivity for a molecular titanium catalyst (13000 g g Ti −1 h −1 , 93 % 1‐butene).