P-Xylene → Chloro-p-xylene

Participants

Reaction Steps

The use of sulfonyl fluorides, instead of sulfonyl chlorides, is essential to the process of the present invention. While not wishing to be bound by theoretical considerations, it appears that when alkyl sulfonyl chlorides react with aromatic hydrocarbons in the presence of aluminum chloride, the major reaction which occurs is chlorination, not sulfonylation, of the aromatic compound. For example, the reaction of p-xylene with methanesulfonyl chloride in the presence of aluminum chloride gave a 70% yield of 2,5-dimethylchlorobenzene and less than 1% yield of 2,5-dimethylphenyl methyl sulfone, as shown below: ##STR3## The corresponding chlorination reaction was found to occur with toluene, xylenes, and mesitylene, often to the virtual exclusion of sulfonylation. This undesired chlorination reaction accounts for the low yields previously reported in attempted alkyl sulfonyl chloride Friedel-Crafts reactions.

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