Chlorination of glycerol with HCl to 1,3-dichloro-2-propanol catalyzed by aliphatic carboxylic acids.

Glycerol oversupplied in biodiesel production can be used as a renewable raw material for producing high-valued chemicals, such as 1,3-dichloro-2-propanol (1,3-DCP), propanediol, acrolein, and acrylic acid. Catalytic chlorination of glycerol to 1,3-DCP is an alternative to propylene chlorination. The catalytic activities of various aliphatic carboxylic acid catalysts for the catalytic chlorination of glycerol with HCl to 1,3-DCP were investigated. When monocarboxylic acids, such as acetic, propanoic, butyric, and hexylic acids, were used as the catalysts, the monocarboxylic acids with the carbon numbers of 3 and 4 favored the glycerol chlorination to 1,3-DCP. When dicarboxylic acids, such as oxalic, malonic, succinic, and adipic acids, were used as the catalysts, the dicarboxylic acids with long carbon chain favored the glycerol chlorination to 1,3-DCP. The highest yield of 1,3-DCP of 88.6% was obtained over adipic acid catalyst after reacting at 110 °C for 14 h. When hydroxylcarboxylic acids, such as citric, malic, and lactic acids, were used as the catalysts, the 1,3-DCP yields were approximately half of those over monocarboxylic and dicarboxylic acid catalysts with the same carbon number, respectively. The steric hindrance effect of carboxylic acids played an important role in glycerol chlorination to 1,3-DCP as compared with their acid strengths. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]