The formation of chlorinated compounds from benzene in a fly ash model system

We have studied the formation of chlorophenols and chlorobenzenes from benzene on an alumina support, impregnated with copper chloride and potassium chloride. Chlorophenols and chlorobenzenes, which are precursors for the formation of PCDDs and PCDFs, are formed from benzene under these conditions, but in too low amounts to subsequently give detectable amounts of PCDDs and PCDFs. When a mixture of 12C/13C benzene was used, only chlorophenols and chlorobenzenes with 12C6 or 13C6 rings were formed. This means that those compounds are formed directly from benzene, formation does not occur through fragmentation of the benzene, followed by recombination. Chlorination of benzene and formation of chlorophenols are likely determined thermodynamically.