Catalyst recycling in the hydroaminomethylation of methyl oleate: A route to novel polyamide monomers

Abstract

This article describes the development of an effective thermomorphic multicomponent solvent (TMS) system for the production of branched polyamide monomers. In this system, methyl oleate, a renewable from fats and oils, and a functionalized amine are used as starting materials in a tandem catalytic reaction, which merges different reaction steps into a single preparative step. This particular TMS system consisted of a heptane/acetonitrile solvent mixture and made reusing the precious rhodium catalyst possible in three recycle runs. A constant yield of 61–65% was obtained for each run due to low‐catalyst leaching. Fortunately, the catalyst system does not require any additional phosphorous ligands and allows high yields. A scale‐up for the production of 10–11 g of the desired product in each run was realized. Subsequent hydrogenation of the product directly provided an amine ester, which is a valuable polyamide monomer.Practical applications: A method was developed to enable access to primary amines via hydroaminomethylation and hydrogenation. The product, a nitrile ester, is a valuable intermediate for polyamide monomers. This nitrile ester was successfully hydrogenated to an amine ester, which features a potential polyamide monomer directly. A catalyst recycle of the homogeneous rhodium complex within the hydroaminomethylation of methyl oleate and an amino nitrile was successfully carried out, enabling constant homogeneous catalyst activity over the course of three recycle runs. A scale‐up to obtain 10–11 g of the hydroaminomethylation product was realized.A general method is described for the conversion of methyl oleate within a hydroaminomethylation reaction. The catalyst can be recovered and reused. Valuable polyamide intermediates were obtained.