Mitsubishi Chemical Corporation

Mitsubishi Petrochemical Company Limited

Norioki Mine

Masahiko Yamagishi

Chikara Sugimoto

Yoshiro Suzuki

Masashi Inaba

Mamoru Mizutani

Minoru Kotato

Yoshiaki Mori

Manabu Okuyama

Toshimitsu Kato

Yoshio Fukui

Tatsuto Yoshioka

Naoki Kato

Seishi Fujii

Naoyuki Watanabe

Tooru Segi

Refined ethylene sulfite exhibits an excellent storage stability when used as a constituent of an electrolyte. A method of producing same has a step of reacting ethylene glycol and thionyl chloride to producing raw ethylene sulfite, a rectifying step for rectifying the raw ethylene sulfite, and a refining process for refining the raw ethylene sulfite or the rectified ethylene sulfite conducted before or after the rectifying step. The refining process is at least one process selected from the group consisting of a washing process, a dehydration process by total reflux distillation, a second rectifying process, and an absorbing process. Refined ethylene sulfite produced according to the method contains chloroethanol in an amount of not more than 1000 ppm.

Method for producing refined ethylene sulfite

A method for preparing a (meth)acrylic acid ester, which comprises reacting (meth)acrylic acid with a C.sub.1-3 alcohol in the presence of a strongly acidic ion exchange resin as a catalyst, wherein the reaction is carried out under reduced pressure while the molar ratio of the alcohol to the (meth)acrylic acid is adjusted to be less than 1, whereby it is possible not only to improve the esterification yield by one pass but also to reduce the amount of a by-product alkoxypropionate which is problematic in the purification system.

Method for preparing (meth)acrylic acid ester

In a method for inhibiting the polymerization of (meth)acrylic acid or esters thereof, the improvement comprising using as a polymerization inhibitor a N-oxyl compound represented by the general formula (1): ##STR1## wherein X represents CH.sub.2, CHOH, C=O, CHCOCH.sub.3 or CHNHCOCH.sub.2, in combination with phosphine compound or a cobalt compound.

Method for inhibiting polymerization of (meth) acrylic acid or esters

Method for producing L-aspartic acid

The present invention provides a method of preparing high purity 2,6-naphthalene dicarboxylic acid in which the contents of coloring substances, heavy metal and bromine compounds can be reduced by dissolving coarse crystals of 2,6-naphthalene dicarboxylic acid containing impurities in supercritical or subcritical water containing an entrainer composed of an organic solvent containing oxygen and having a specific solubility parameter, and by cooling an obtained solution to cause crystals to precipitate so as to separate the crystals from mother liquor.

Method of preparing high purity 2,6-naphthalene dicarboxylic acid

4,4'-Biphenol is prepared through debutylation of 3,3', 5,5'-tetra-tert-butyl-4,4'-biphenol in an organic solvent in the presence of an acid catalyst wherein the debutylation is carried out continuously using at least two reactors aligned in series, with a high yield and high purity on an industrial level.

Method for preparing 4,4'-biphenol

A process for preparing 4,4'-dihydroxybiphenyl is disclosed, which comprises debutylation of 3,3', 5,5'-tetra-t-butyl-4,4'-dihydroxybiphenyl in an organic solvent in the presence of an acid catalyst, wherein said debutylation is carried out in the presence of water and/or a lower alcohol. The desired product can be obtained at a high purity in a high yield.

Process for preparing 4,4'-dihydroxybiphenyl

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Yokkaichi, Japan

Norioki Mine