Direct Preparation Of Dichloropropanol From Glycerol And Hydrochloric Acid Gas In A Solvent-free Batch Reactor: Effect Of Experimental Conditions

摘要

Solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas was carried out in a batch reactor with a variation of reaction conditions (agitation speed, reaction time, reaction temperature, and reaction pressure), amount of H_3PW_(12)O_(40) catalyst, and amount of water absorbent (silica gel blue). The reaction was conducted at high agitation speed in order to avoid mass transfer limitation between glycerol and hydrochloric acid gas. In the direct preparation of DCP from glycerol and hydrochloric acid gas, DCP formation was increased with increasing reaction time, reaction temperature, and reaction pressure. Chlorination of glycerol occurred via the following consecutive reaction steps: glycerol→monochloropropanediol (MCPD)→dichloropropanol (DCP)→trichlo-ropropane (TCP). Reaction rate decreased in the order of first-step reaction>second-step reaction>third-step reaction. The presence of H_3PW_(12)O_(40) catalyst and water absorbent (silica gel blue) enhanced the formation of DCP. DCP formation was increased with increasing the amount of H_3PW_(12)O_(40) catalyst and water absorbent (silica gel blue). Strong Bronsted acid site of H_3PW_(12)O_(40) catalyst and water removal from the reaction system favorably served in improving DCP formation.