Merging biomass and CO2 utilization; process design and assessment on simultaneous production of lactic acid and formic acid from glycerol and CO2

Abstract

Biomass and CO2 conversion is receiving great attention to address climate change and energy crisis. Bio-based lactic acid (LA) appeals industries, however, current technologies suffer from low productivity and waste production. The transfer hydrogenation of glycerol and CO2 to LA and formic acid (FA) has been proposed as an alternative pathway, but further development and process design are required. This study proposes the integrated process for conversion of glycerol and CO2 to LA and FA derivatives. A two-pot/two-step transfer hydrogenation was demonstrated to achieve high products yield, catalyst reusability, and product separation. The esterification of lactate and formate salts to corresponding esters utilizing CO2 was also developed, which reduces H2SO4 consumption and K2SO4 waste. Techno-economic and life cycle assessments reveal that CO2 utilization is crucial for high economic benefit and low climate change impact. This study shows integrating biomass and CO2 could have synergies to design greener process.