Process for the preparation of halophthalic anhydrides
AssigneeOccidental Chemical Corporation
InventorsKarl W. Seper, Edward J. Colman, David Y. Tang, Mary K. Cocoman, Harry E. Buckholtz
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Abstract
A process for the preparation of a halophthalic anhydride, such as chlorophthalic anhydride, comprising the liquid phase reaction of bromine with a halogen substituted hexa- or tetra-hydrophthalic anhydride to produce halophthalic anhydride and gaseous HBr, and reacting the gaseous HBr with chlorine to regenerate bromine.
Claims15
A process for the preparation of a halogen substituted phthalic anhydride of the formula ##STR5## wherein X is independently F-, Cl-, Br-, or I-;
- and n is 1 or 2, which comprises
- a) reacting in the liquid phase at temperatures below about 230.degree. Celsius, bromine with a halogen substituted hexa-, or tetra- hydrophthalo- reactant of the formula ##STR6## wherein Q is monohalo and is the same as X or is gem-dihalo, wherein at least one halogen is the same as X, and n is the same number as in formula I, with the proviso that each monohalo is directly attached to a double bond carbon and each gem-dihalo is directly attached to a non-double bond carbon and with the proviso that the initial reaction is carried out at a temperature below 170.degree. Celsius to produce the halogen substituted phthalo compound, of Formula I, and gaseous HBr;
- and
- B) reacting the gaseous HBr with chlorine to produce bromine and HCl.
A process for the preparation of halogen substituted phthalic anhydrides of the formula:
- ##STR7## where each X is independently F-, Cl-, Br-, and n is 1 or 2, which comprises
- (A) reacting bromine with a halogen-substituted tetra-hydrophthalic anhydride reactant of the formula:
- ##STR8## where Q is monohalo and is the same as X with the proviso that the monohalo is directly attached to a double bond carbon in the liquid phase at a temperature of 0.degree. to 190.degree. Celsius to produce the compound of Formula I and gaseous HBr, and
- (B) reacting the gaseous HBr with chlorine to produce bromine and HCl.
A process for the preparation of a halogen-substituted phthalic anhydride of the formula:
- ##STR9## where each X is independently F-, Cl-, or Br- and n is 1 or 2, comprising the liquid phase reaction of bromine with a halogen substituted tetrahydrophthalic anhydride reactant of the formula:
- ##STR10## where Q is halo and is the same as X and n is the same number as in Formula I, with the proviso that each halo is directly attached to a double bond carbon, to produce the compound of Formula I and gaseous HBr and regenerating the bromine reactant;
- wherein the process comprises the steps of:
- (A) adding the major portion of the bromine to a reaction mixture comprising the reactant of Formula II and maintaining the reaction mixture at a temperature of about 90.degree. to 125.degree. Celsius until the bromine is substantially consumed with concurrent formation of gaseous HBr therefrom;
- (B) increasing the temperature to about 130.degree. to 145.degree. Celsius and maintaining thereat while the remaining portion of the bromine is added and substantially consumed with concurrent formation of HBr therefrom;
- (C) increasing the temperature to about 150.degree. to 190.degree. Celsius to remove any remaining dissolved HBr from the liquid phase;
- and
- (D) reacting the gaseous HBr with chlorine to produce bromine and HCl.
Dependencies are inferred from the claim text.