Hydroaminomethylation of methyl 10-undecenoate with integrated catalyst recycling via a thermomorphic multiphase system for the continuous production of renewable amines

Abstract

A thermomorphic multiphase system (TMS) consisting of methanol and n-dodecane was successfully applied to the hydroaminomethylation (HAM) of the renewable methyl 10-undecenoate. By using different amine substrates, a variety of α,ω-bifunctional products with potential use as intermediates for the polymer industry were obtained with high yields of up to 96%. The full potential of our TMS was shown in a miniplant, with over 90 h of continuous operation showing a stable selectivity towards the desired amine product of 80%. Combining the TMS with an OSN membrane for continuous separation of the by-product water from the reaction system was a key factor for the excellent results. The water concentration in the recycle could be kept below 4% so that only 3% of the undesired aldol condensate was obtained after 90 hours. The low catalyst leaching via the TMS and the OSN membrane is particularly remarkable. The total loss of rhodium over the 90 hours continuous operation is 2.5% of the initial amount used, and for the ligand SulfoXantphos only 0.4% of the initial amount. The loss of rhodium via the TMS and the OSN is 6 ppm per produced desired amine product.