Regeneration of H3PW12O40 catalyst in the direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas

Methods for regenerating H 3 PW 12 O 40 catalyst in the solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas were investigated. Regenerated H 3 PW 12 O 40 catalyst was then applied to the solvent-free direct preparation of DCP. In the solvent-free direct preparation of DCP, selectivity for DCP over H 3 PW 12 O 40 catalyst regenerated by method I (recovery of solid H 3 PW 12 O 40 catalyst by evaporating homogeneous liquidphase product solution) significantly decreased with increasing recycling run, while that over H 3 PW 12 O 40 catalyst regenerated by method II (regeneration of H 3 PW 12 O 40 catalyst by oxidative calcination of solid product recovered by method I) was slightly decreased with no significant catalyst deactivation with respect to recycling run. On the other hand, selectivity for DCP over H 3 PW 12 O 40 catalyst regenerated by method III (regeneration of H 3 PW 12 O 40 catalyst by recrystallization and subsequent oxidative calcination of solid product recovered by method II) was the same as that over fresh catalyst without any catalyst deactivation with respect to recycling run. Thus, method III was found to be the most efficient method for the regeneration of H 3 PW 12 O 40 catalyst.