Production of acid chloride

PURPOSE:When an acid chloride is prepared by reaction of the acid anhydride with a chlorinating agent, zirconium tetrachloride, which is readily available and easy-to- handle, is used as the chlorinating agent to produce the acid chloride in a short time in high yield and facilitate the separation and purification. CONSTITUTION:The reaction between an acid anhydride of formula I (R is residue of aliphatic acid or aromatic acid) and zirconium tetrachloride of formula II is conducted in an appropriate organic solvent, preferably diethyl ether being readily removed, at 10-30 deg.C for 10-20min to produce the acid chloride of formula III in high yield. Zirconium tetrachloride, the chlorinating agent, is relatively stable to water, thus easy-to-handle. Further, this process extremely shortens the reaction time and the reaction proceeds quantitatively at room temperature to produce no by- products boiling at low temperature. Therefore, the separation and purification of the acid chloride are readily effected.