Kuraray Co., Ltd.

Mitsui Chemicals, Inc.

Mitsui Toatsu Chemicals, Incorporated

Rensuke Ikarashi

Takashi Fukumoto

Takeshi Isobe

Yoshihiro Sezaki

Hirozo Segawa

Morimasa Kuragano

Katsuji Yoguchi

Minoru Koshibe

Nobutaka Ueda

Kazuo Wakimura

Shin-ichi Tadokoro

Koji Fujita

Tadaharu Hase

Process for producing 2-azabicyclo&lsqb;2.2.1&rsqb;hept-5-en-3-one

A process for producing 2-azabicyclo[2.2.1]hept-5-en-3-one is provided by reacting a sulfonyl cyanide represented by the general formula R--SO.sub.2 CN (in which R represents an alkyl group or a phenyl group which may have a substituent), in the presence of water and in a hydrocarbon solvent at a pH of 4 to 7 inclusive. 2-Azabicyclo[2.2.1]hept-5-en-3-one can be produced in a high yield and a high purity in one step process, with a reduced amount of solvent used, safely and with good productivity. A method of crystallizing 2-azabicyclo[2.2.1]hept-5-en-3-one is also provided, which includes dissolving 2-azabicyclo[2.2.1]hept-5-en-3-one into an organic solvent mainly including at least one of diisopropyl ether and methyl tertiary butyl ether, cooling the solution to deposit crystals of 2-azabicyclo[2.2.1]hept-5-en-3-one. Finely divided particulate crystals of 2-azabicyclo[2.2.1]hept-5-en-3-one excellent in fluidity and handleability can be obtained with a simple procedure and in a high recovery rate.

Process for producing and method of crystallizing

A process for producing 2-azabicyclo[2.2.1]hept-5-en-3-one is provided by reacting a sulfonyl cyanide represented by the general formula R-SO.sub.2 CN (in which R represents an alkyl group or a phenyl group which may have a substituent), in the presence of water and in a hydrocarbon solvent at a pH of 4 to 7 inclusive. 2-Azabicyclo[2.2.1]hept-5-en-3-one can be produced in a high yield and a high purity in one step process, with a reduced amount of solvent used, safely and with good productivity. A method of crystallizing 2-azabicyclo[2.2.1]hept-5-en-3-one is also provided, which includes dissolving 2-azabicyclo[2.2.1]hept-5-en-3-one into an organic solvent mainly including at least one of diisopropyl ether and methyl tertiary butyl ether, cooling the solution to deposit crystals of 2-azabicyclo[2.2.1]hept-5-en-3-one. Finely divided particulate crystals of 2-azabicyclo[2.2.1]hept-5-en-3-one excellent in fluidity and handleability can be obtained with a simple procedure and in a high recovery rate.

A process for producing refined methacrylic acid comprising the steps of oxidizing methacrolein and the like catalytically in a vapor phase to form a methacrylic acid-containing gas, cooling and condensing the gas to an aqueous methacrylic acid solution, adding to the solution an organic solvent that forms two liquid phases with water to carry out an extraction operation and thereby to obtain an extract, bringing the extract into contact with water to mix them together, separating the mixture into an organic phase and a water phase, and distilling the organic phase. According to this process, highly refined methacrylic acid containing little dibasic acids such as maleic acid and citraconic acid can be obtained economically and without increasing wastes that are unrecoverable to the process.

Process for refining methacrylic acid

A process is provided for the purification of methacrylic acid. The process can easily remove dibasic acids and aldehydes containing in trace amounts as impurities. According to the process, crude methacrylic acid obtained as an aqueous solution by vapor-phase catalytic oxidation of isobutylene, tertiary butanol, methacrolein or isobutyl aldehyde is treated with at least one compound selected from the group consisting of m-aminophenol, m-phenylenediamine, 2,4-diaminotoluene and 2,4-diamino-diphenylamine, followed by distillation, optionally, in the presence of a p-phenylene diamine.

Purification process of methacrylic acid

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Kitakanbara-gun, Japan

Rensuke Ikarashi