The invention relates to a method for synthesizing dichloropropanol by catalyzing
glycerol for chlorination under the existence of
dicarboxylic acid-
rare earth chloride, which comprises the following steps of: mixing
glycerol and a
dicarboxylic acid-
rare earth chloride composite catalyst in a chloridizing reactor R-1, and then introducing
chlorine hydride gas, constantly evaporating out water and partial dichloropropanol generated in the reactor; introducing
chlorine hydride as a
tail gas into a chloridizing reactor R-2 filled with the
glycerol and the catalyst; after the chlorination of the reactor R-1 is ended, evaporating dichloropropanol by decompression and then adding the glycerol for further chlorination; during the
distillation of the chloridizing reactor R-1, starting to introduce
chlorine hydride into the chloridizing reactor R-2, and the chlorine hydride as the
tail gas into a chloridizing reactor R-3, wherein the glycerol and the catalyst added into the chloridizing reactors R-1, R-2 and R-3 have the same dosage; after the chlorination of the chloridizing reactor R-2 is ended, repeating the procedures of
distillation, feeding and chlorination in the chloridizing reactor R-1; connecting the chloridizing reactors R-1,R-2 and R-3 from head to
tail, and introducing the chlorine hydride as the tail gas into the chloridizing reactor R-1 while introducing the chlorine hydride into the chloridizing reactor R-3; transferring a mixed liquor of the dichloropropanol, water and the chlorine hydride to a
distillation still, and adding an
organic solvent to remove water by azeotropy. The method has the advantages of high
reaction speed, high utilization ratio of the chlorine hydride and high yield.