Synthesis of Acrylonitrile from Renewable Lactic Acid.

Acrylonitrile (ACN) is widely used as monomer in the synthesis of polymers and carbon fibers. Nowadays, its production is based on fossil resources. Herein, we present an alternative process based on renewable resources. Lactic acid (LA) obtained by fermentation of biomass is converted to ACN in two steps with an overall selectivity of 57%. In the first step, a direct amidation of LA in the presence of water is conducted at 230 °C. Zeolites can catalyze the formation of lactamide, and a selectivity of 92% is reached at 33% conversion with NH4-ZSM-5. In the second step, the dehydration of lactamide to ACN is carried out with the assistance of acetic anhydride, and an ACN yield of 62% is achieved in the dehydration.