Clean process for preparing a chloroformyl-substituted benzene by oxidation of a tail gas hydrogen chloride from a chlorination reaction and a chloroacylation reaction and recycling of the resulting oxidation product chlorine gas into the chlorination reaction. The present invention provides a clean process for preparing a polymer-grade chloroformyl-substituted benzene.

Clean process for preparing a chloroformyl-substituted benzene by oxidation of a tail gas hydrogen chloride from a chlorination reaction and a chloroacylation reaction and recycling of the resulting oxidation product chlorine gas into the chlorination reaction. The present invention provides a clean process for preparing a polymer-grade chloroformyl-substituted benzene.