Nippon Shokubai Kagaku Kogyo Co., Ltd.

Sokubai Kagaku Kogyo, Co., Ltd.

Kentaro Sakamoto

Yuichi Kita

Masao Baba

Atsushi Okubo

Takahisa Sato

Kazuo Kishino

Akio Fukui

Koichi Nakagawa

Hitoshi Kanei

Masakazu Nakagawa

Yoichi Nakagawa

Takeshi Okuno

Tomoaki Tobo

The present invention is directed to an acrylonitrile maleimides solution composition of highly desirable shelf like, having the acid component in said acrylonitrile maleimides soltuion adjusted to a level of no more than 0.1% by weight based on the amount of said maleimides contained in said solution and having a polymerization inhibitor in said solution adjusted to a level in the range of 0.0001 to 1% by weight based on the amount of said solution, and a method for the production thereof.

Acrylonitrile maleimides solution composition of improved shelf life and

A method for inhibiting polymerization of a maleimide, which comprises adding to said maleimide, as a polymerization inhibitor, at least one compound selected from the group consisting of thiodipropionic esters, 4-t-butyl-catechol, 2,4-dimethyl-6-t-butyl phenol, 2,5-di-t-butylhydroquinone, 2-t-butyl-hydroquinone, 2,4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-trizaine, 2,2'-thiobis-(4-methyl-6-t-butylphenol), 4,4'-thiobis-(6-butyl-m-cresol), and triethyleneglycol-bis-[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate].

Method for inhibiting polymerization of maleimides

A method for the production of a maleimide by dehydration and ring-closure of maleinamic acid obtained by the reaction of maleic anhydride with an amine, which method is characterized by effecting ring-closure imidation of said maleinamic acid by heating said maleinamic acid in a water-insoluble or water-immiscible inert organic non-polar solvent in the presence of a catalyst of an amine salt produced from the amine and an acid, a mixture of the amine salt and the acid, or a supported catalyst on a solid carrier the catalyst or the acid.

Method for production of maleimides

A method for the production of maleimides, which comprises subjecting maleinamic acids to ring-closure imidation in an organic solvent capable of forming an azeotrope with water in the presence of an acid catalyst at a temperature in the range of 120.degree. to 250.degree. C. while removing the formed water in the form of an azeotrope with said organic solvent and thereafter purifying the produced maleimides.

A method for the production of maleimides, which comprises subjecting maleinamic acids to ring-closure imidation in an organic solvent capable of forming an azeotrope with water in the presence of an acid catalyst at a temperature in the range of 120.degree. C. to 250.degree. C. while removing the formed water in the form of an azeotrope with said organic solvent and thereafter purifying the produced maleimides.

Method for production of N-phenyl and N-cyclohexyl maleimides

A method for the manufacture of high-purity phthalic anhydride, which comprises exposing crude phthalic anhydride obtained by vapor-phase catalytic oxidation of ortho-xylene to contact with a gas containing molecular oxygen at an elevated temperature in the presence of an alkali metal salt of at least one carboxylic acid selected from the group consisting of maleic acid, succinic acid and benzoic acid, and optionally a manganese-containing alloy, and subsequently subjecting the resultant reaction mixture to distillation.

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Hyogo, Japan

Kentaro Sakamoto