Highly selective production of propionic acid from lactic acid catalyzed by NaI

• Published in: Green chemistry : an international journal and green chemistry resource : GC 2020-11, Vol.22 (21), p.7468-7475
• Main Authors: Liu, Shengqin, Feng, Huan, Li, Teng, Wang, Yantao, Rong, Nianxin, Yang, Weiran
• Format: Article
• Language: English
• Subjects: Acids; Carboxyl group; Catalysts; Cellulose; Feed industry; Food industry; Green chemistry; Hydroxyl groups; Lactic acid; Petrochemicals industry; Propionic acid
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/d0gc02676j

Propionic acid (PA), a valuable chemical widely used in the food and feed industry, is currently produced by the petrochemical industry. Selective production of PA from bio-based lactic acid (LA) is difficult due to the high activation energy of the hydroxyl group at the α position of the carboxyl group. Herein, a metal-free catalytic system for the highly selective transformation of bio-based LA to PA, which was used as the solvent to simplify the separation step, is reported using NaI as the catalyst. Under the optimal reaction conditions, a >99% yield of PA can be obtained from LA. A heat-induced radical-activated hydrogen mechanism was proposed based on the kinetic study and intermediate capture. The metal-free system can be reused five times without any loss in activity, and the PA product is easily separated. In addition, a two-step method using cellulose as the raw material to produce PA was conducted. This strategy offers a green and efficient approach to synthesize PA from biomass resources. Efficient and highly selective production of propionic acid from biomass derived lactic acid was realized using I − /H 2 without adding other strong acids or metal catalysts.