Abstract: A stabilization method of a vinyl compound with hydroxy group of an improved stability is achieved by preventing it from being denatured on storage, transportation, manufacturing process while maintaining its reactivity. A composition containing the vinyl compound with hydroxy group of an improved stability is obtained by the described stabilization method. The stabilization method is characterized by coexisting a vinyl compound with hydroxy group of formula (1), a primary antioxidant, alcohol and/or water, ##STR1## wherein R is a hydrogen atom or an organic residue, X is a --CN group, a --COR.sub.0 group or a --COOR.sub.0 group, and R.sub.0 is a hydrogen atom or an organic residue. In this stabilization method, not less than 50 ppm of alcohol and/or water is added with respect to the vinyl compound with hydroxy group. The stabilization method may be achieved by coexisting the above-defined vinyl compound with hydroxy group, the primary antioxidant and organic acid.

Abstract: A vinyl compound having a hydroxy group of the formula (1) ##STR1## wherein R is a hydrogen atom or an organic residue, X is a --CN group, a --COR.sub.0 group or a --COOR.sub.0 group and R.sub.0 is a hydrogen atom or an organic residue, is prepared by reacting a vinyl compound of the formula (2) ##STR2## wherein X is a --CN group, a --COR.sub.0 group or a --COOR.sub.0 group and R.sub.0 is a hydrogen atom or an organic residue, with an aldehyde series compound in the presence of a tertiary amine compound, and water in a sufficient amount for forming an aqueous phase upon the completion of the reaction. In this method, since the aqueous phase is formed upon the completion of the reaction, the organic phase including the vinyl compound having a hydroxy group and the aqueous phase including the tertiary amine compound can be easily separated.

Abstract: The present invention provides a stabilized maleimide compound which is hard to discolor during storage. The maleimide compound has a content of primary amines of not more than 500 ppm or further has a content of maleic anhydride in the range of 5 to 2,000 ppm or a content of 2-amino-N-substituted succinimide compounds of not more than 300 ppm. Furthermore, it is preferable that the content of chlorine compounds reduced as a chlorine atom is not more than 10 ppm and further the content of volatile components having a boiling point of not more than 200.degree. C. at normal pressure is not more than 2,000 ppm.

Abstract: In the production of an N-unsubstituted maleinimide by the ring-closing alcohol-removing treatment of an N-unsubstituted maleinamic ester for conversion into an imide, an acid catalyst or a mono(cyclo)alkyl sulfuric ester is used for the reaction. In this case, the alcohol concentration in the reaction solution is preferable to be adjusted to a low level. By using a maleinamic acid and an alcohol in conjunction with an inert solvent and an acid catalyst, a mixture of maleinamic acid with an acid catalyst, or a mono(cyclo)alkyl sulfuric ester, a corresponding maleinamic ester is obtained.

Abstract: A method for handling a maleimide, which method comprises handling said maleimide in the presence of a stabilizer at a temperature exceeding the melting point thereof in a state kept in contact with a gas phase having a molecular oxygen content of not more than 10% by volume.

Abstract: 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.

Abstract: 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].

Abstract: A method for the production of a maleimide, which comprises effecting a former-stage reaction by adding maleic anhydride and a primary amine in amounts such that the molar ratio of said maleic anhydride to said primary amine is less than 1 under application of heat to a water-insoluble or water-immisible inert organic solvent containing an acid catalyst and subsequently carrying out a latter-stage reaction by adding to the reaction system maleic anhydride in an amount such that the molar ratio of the total amount of maleic anhydride to be added to said reaction system to the total amount of said primary amine added to said reaction system exceeds 1.

Abstract: Method for the transportation or storage of N-phenyl maleimide, which method comprises mixing N-phenyl maleimide with maleic anhydride in a ratio of 1 to 90 parts by weight of N-phenyl maleimide to 99 to 10 parts by weight of maleic anhydride and handling the resultant mixture in a molten state in the presence of a polymerization inhibitor, and a composition of liquid state.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.