Patent ID: 7541489
Filing Date: 2009-06-02
Classification: C07C

Abstract:
1. A method of preparing a halophthalic acid, said method comprising the steps of: contacting in a liquid phase reaction mixture at least one halogen-substituted ortho-xylene with oxygen and acetic acid at a temperature in a range between about 120° C. and about 220° C. in the presence of a catalyst system, said catalyst system consisting essentially of a source of cobalt ions, a source of manganese ions, and a source of bromide ions, said reaction mixture being characterized by an initial molar ratio of cobalt ion to halogen-substituted ortho-xylene of less than about 2%, an initial molar ratio of manganese ion to halogen-substituted ortho-xylene of less than about 1.5%, and an initial molar ratio of bromide ion to halogen-substituted ortho-xylene of less than about 0.5%, said oxygen being present in an amount corresponding to a partial pressure of oxygen in a range between about 0.00001 and about 15 bar, to provide a product mixture comprising less than 10 percent halogen-substituted ortho-xylene starting material, a halophthalic acid product, and less than about 10,000 parts per million halobenzoic acid by-product and less than 1000 parts per million halophthalide by-product based on a total amount of halophthalic acid present in the product mixture.