Recyclable homogeneous catalyst for the hydroesterification of methyl oleate in thermomorphic solvent systems

Abstract

In the development of commodity markets alternatives to fossil resources are of high interest. One alternative is the usage of oleo compounds. In this paper an atom economic hydroesterification of methyl oleate to linear and branched diesters is described. The selectivity to linear or branched products can be influenced by reaction parameters. These diesters can be used in polymers, plasticizers, lubricants or to adjust crystallinity in these materials. To the best of our knowledge we provide the first efficient catalyst recycling in the hydroesterification of fatty compounds. The catalyst system of palladium and XANTphos proved to be very stable. Products with the tough palladium XANTphos catalyst are mostly branched, while the selectivity to linear products can be influenced by temperature, carbon monoxide pressure and choice of solvent up to 64%. A high selectivity of 94% towards branched products was obtained if no solvent was used. Separation of products and catalyst was realised using thermomorphic solvent systems (TMS). The catalyst was recycled in a methanol/decane system with low leaching values. A recycling of the catalyst phase was conducted three times with no significant activity loss.