Preparation of 2,5-dichlorobenzophenones
AssigneeMaxdem Incorporated
InventorsYing Wang, Mark S. Trimmer
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Abstract
A method for preparing isomerically pure 2,5-dichlorobenzophenones in good to high yields is provided. The invention comprises Friedel-Crafts aroylation of 1,4-dichlorobenzene using an aroyl halide or aromatic anhydride and at least one Lewis acid, the latter being present in an amount of at least about 1.1 mole per mole of aroyl halide or aromatic anhydride, preferably about 1.5 moles per mole of aroyl halide or aromatic anhydride and, more preferably, from about 2 to about 2.5 moles of Lewis acid per mole of aroyl halide or aromatic anhydride. Preferably, the molar ratio of 1,4-dichlorobenzene to aroyl halide ranges from about 1.2:1 to about 8:1.
Claims22
A method for preparing 2,5-dichlorobenzophenones, comprising:
- Friedel-Crafts aroylation of 1,4-dichlorobenzene using an aroyl halide or an aromatic anhydride, and at least one Lewis acid present in an amount of at least about 1.5 mole per mole of aroyl halide or aromatic anhydride.
A method according to claim wherein the aromatic anhydride is selected from the group consisting of phthalic anhydride, substituted phthalic anhydrides, benzoic anhydride, and substituted benzoic anhydrides.
A method according to claim wherein 1,4-dichlorobenzene and the aroyl halide are present in a ratio of at least about 1.2 mole of 1,4-dichlorobenzene per mole of the aroyl halide.
A method according to claim wherein the Friedel-Crafts aroylation is carried out at a temperature of from about 0.degree. to about 250.degree. C.
A method for preparing 2,5 -dichlorobenzophenones, comprising:
- Friedel-Crafts aroylation of 1,4-dichlorobenzene using an aroyl halide or an aromatic anhydride, and at least one Lewis acid, in the absence of nitrobenzene;
- wherein the molar ratio of Lewis acid to 1,4-dichlorobenzene to aroyl halide or aromatic anhydride is no less than about 1.1:1.3:1, and the 2,5-dichlorobenzophenones are obtained in at least about 50% yield.
Dependencies are inferred from the claim text.