an improved process for production of allyl chloride which comprises thermally chlorinating propylene above 300 ° c ., but below that at which substantial carbon formation is effected , separating the allyl chloride from its by - products , subjecting the unsaturated compounds in said by - products to a low temperature chlorination , separating the 1 , 2 - dichloropropane from the products of said low temperature chlorination , and passing said 1 , 2 - dichloropropane to a cracking furnace . the effluent from the cracking furnace can be recycled to the allyl chloride finishing system by adding it to the high temperature propylene chlorination reactor effluent . reaction temperatures are optimized to eliminate problems caused by carbon formation in the high temperature chlorination reactor , while overall yields of allyl chloride are increased and effluents which are ecologically and economically undesirable are reduced .