- Synthesis of 3,5-dichloroalkylbenzene and recovery of 1,3-dichlorobenzene
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A process for synthesizing 3,5-dichloroalkylbenzene and recovering 1,3-dichlorobenzene from a starting mixture of 1,3- and 1,4-dichlorobenzenes. The process includes the sequential steps of selectively alkylating the 1,3-dichlorobenzene in the starting mixture; isomerizing a portion of the 2,4-dichloroalkylbenzene produced to 3,5-dichloroalkylbenzene; separating the 1,4-dichlorobenzene from the isomeric mixture of dichlorocumenes; and selectively transalkylating the dichlorocumenes to yield alkylbenzene, 3,5-dichloroalkylbenzene and 1,3-dichlorobenzene. By selectively alkylating only a portion of the 1,3-dichlorobenzene, the reaction products are obtained in good yield and substantially free of undesirable by-products.
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- Process for preparing 3,5-dichloro-α-methylstyrene
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In the preparation of 3,5-dichloro-α-methylstyrene by isopropylation of an m/p-dichlorobenzene mixture, isomerization of the resulting alkylation mixture, subsequent side chain bromination of the alkylation mixture and dehydrobromination of the resulting bromination mixture, the improvement which comprises reacting an excess of an m/p-dichlorobenzene mixture which contains at least 50% by weight of m-dichlorobenzene with isopropyl halide, isomerizing the resulting alkylation mixture under pressure in the presence of aluminum chloride until thermodynamic equilibrium has been attained, separating off the isomerized alkylation mixture from the unreacted m/p-dichlorobenzene mixture, and recycling the unreacted mixture for further reaction.
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