Preferential alkylation or acylation of meta-disubstituted benzenes
AssigneeThe Dow Chemical Company
InventorsJames R. Dewald, Lowell D. Markley
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Abstract
In a mixture of isomers of a disubstituted benzene such as dichlorobenzene, the meta-disubstituted isomer is preferentially reacted with an alkylating or acylating agent, e.g., an alkyl halide, by contacting the mixture with the agent in the presence of a Friedel-Craft catalyst at a temperature of less than about 60.degree. C. The resulting alkylated or acylated meta-isomer can be readily separated from the reaction mixture by simple distillation.
Claims11
In an isomeric mixture comprising para- and meta-disubstituted benzenes having two halogen substituents, a process for the alkylation of the meta-disubstituted benzene which process comprises contacting the isomeric mixture with an alkylating agent in the presence of a catalytic amount of a Friedel-Crafts catalyst at a reaction temperature less than about 60.degree. C such that the meta-disubstituted benzene is preferentially alkylated.
In an isomeric mixture comprising disubstituted benzenes represented by the formulas:
- ##STR3## wherein each X is individually halogen and R is hydrogen, a process for the preferential alkylation of the disubstituted benzene of formula (I) which process comprises contacting the isomeric mixture with an alkylating agent in the presence of a catalytic amount of an aluminum trihalide at a reaction temperature of between about -20.degree. C and about 60.degree. C.
In an isomeric mixture comprising disubstituted benzenes represented by the formulas:
- ##STR4## wherein each X is individually halogen and R is alkyl, a process for the preferential alkylation of the disubstituted benzene of formula (I) which process comprises contacting the isomeric mixture with an alkylating agent in the presence of a catalytic amount of a Friedel-Crafts catalyst at a reaction temperature of between about -20.degree. C and about 60.degree. C.
In an isomeric mixture comprising para- and m-dihalobenzenes, a process for the alkylation of the m-dihalobenzene which process comprises contacting the isomeric mixture with an alkylating agent in the presence of a catalytic amount of a Friedel-Crafts catalyst at a reaction temperature less than about 60.degree. C such that the m-dihalobenzene is preferentially alkylated.
Dependencies are inferred from the claim text.