1.With the aid of the addition reaction between phosphorus pentachloride and 1,3-butadiene, 2-chloro-3-butenylphosphonic dichloride was prepared.2.The methyl, ethyl, propyl, isopropyl, butyl, isobutyl, allyl, hexyl, 2-methoxyethyl, and 2-ethoxyethyl esters of 2-chloro-3-butenylphosphonic acid were prepared by the action of alcohols on 2-chloro-3-butenylphosphonic dichloride, and some of their properties were determined.3.By reaction between alcoholic potash and esters of 2-chloro-3-butenylphosphonic acid, the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, allyl, hexyl, 2-methoxyethyl, and 2-ethoxyethyl esters of 1,3-butadienylphosphonic acid were synthesized.