A soln of (CAS NO. ) (300mL) in C₆H₆ (200mL) was washed with two 100mL portions of cold 5% NaHCO₃ soln, separated, dried with CaCl₂ and distd.

Repeated fractional distn at 4mm Hg through a glass helices-packed column (avoiding porous porcelain or silicon-carbide boiling chips, and hydrocarbon or silicon greases on the ground joints) gave benzoyl chloride that did not darken on addition of AlCl₃. Further purification was achieved by adding 3 mole% each of AlCl₃ and toluene, standing overnight, and distilling off the benzoyl chloride at 1-2mm. Refluxing for 2h with an equal weight of chloride before distn, has also been used.