Analysis on the production technology of benzaldehyde

benzaldehyde was trial produced by a new process which comprised following steps:(1)photochlorinating the side chain of toluene to generate benzyl dichloride and controlling the forming amount of benzyl trichloride;(2)rectifying to remove benzyl chloride which was recycled;(3)hydrolyzing the fraction containing high content of benzyl dichloride to produce benzaldehyde;(4)distilling further to obtain high purity (≥99.5%) product of benzaldehyde.The problems existing in the trial production were analyzed and solutions and measures are raised.The key points in operation were discussed.