Pd-catalyzed telomerization of butadiene and methanol with direct catalyst recycling using a liquid-ionic liquid biphasic, continuous process

The telomerization of 1,3-butadiene with methanol in the presence of a phosphine modified palladium catalyst was investigated in liquid-ionic liquid biphasic systems. Suitable ionic liquids were pre-selected from computational a priori COSMO-RS screening and tested in a batch autoclave. The Pd leaching could be suppressed significantly when the ligand TPPTS was used instead of the monosulfonated ligand TPPMS. The two most promising ionic liquids [EMMIM][NTf2] and [BMMIM][NTf2] were used to immobilize the Pd-TPPTS catalyst in a continuous loop reactor with integrated separation. While the monosulfonated TPPMS ligand failed to efficiently immobilize the catalyst in the ionic liquid, the TPPTS ligand resulted in very good catalyst immobilization and a constant conversion was maintained for more than 200 h time-on-stream.