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, an alternative process based on renewable resources is presented. Lactic acid (LA), which can be obtained by fermentation of biomass, was 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 was conducted at 230 °C. Zeolites can catalyze the formation of lactamide, and a selectivity of 92 % was reached at 33 % conversion with NH₄ -ZSM-5. In the second step, the dehydration of lactamide to ACN was performed with acetic anhydride, and an ACN selectivity of 62 % was achieved at full conversion.