Daicel Chemical Industries, Ltd.

Kiyokazu Murata

Toyokazu Yagii

Teruo Itokazu

Hiroyuki Miura

Hidetaka Kojima

Yasutaka Tanaka

Kenji Oka

Mamoru Watabiki

Kozo Kawahashi

Hiroshi Oda

Toshihide Maruyama

A process produces a corresponding dicarboxylic acid by subjecting a cycloalkane to an oxidative cleavage reaction with oxygen in the presence of a catalyst in a liquid phase using a continuous reactor, in which a residence time &#x3c4; (hr) satisfies the following condition: 0.1&#x2266;&#x3c4;&#x2266;50/c, wherein c is the proportion (% by weight) of the cycloalkane to the total weight of a charged liquid. The catalyst includes, for example, cobalt compounds, manganese compounds, and mixtures of these compounds, as well as imide compounds having at least one cyclic imide skeleton.

Process for producing dicarboxylic acid

An aliphatic diisocyanate compound is prepared in a high yield by reacting dimethyl carbonate with an aliphatic diamine in the presence of an alkali catalyst to produce a corresponding urethane compound; and, within 48 hours after the completion of the preparation of the urethane compound, thermally decomposing the urethane compound under a reduced pressure of 1 to 700 Torr in a high-boiling-point solvent.

Process for preparation of isocyanate compounds

A diisocyanate compound substantially free from chlorine is prepared by the following consecutive steps (1), (2) and (3):

Packing material for high-performance liquid chromatography and process

A process for continuously producing aromatic carbonates comprising continuously feeding a dialkyl carbonate, an aromatic hydroxy compound, and a catalyst to a reactor equipped with a distillation tower, continuously distilling off a by-produced aliphatic alcohol from the distillation tower so as to keep the aliphatic alcohol concentration in the reactor at 2% by weight or less, and continuously withdrawing produced alkylaryl carbonate and/or diaryl carbonate and the catalyst from the reactor; and a process for continuously producing a diaryl carbonate comprising continuously feeding an alkylaryl carbonate and a catalyst to a reactor equipped with a distillation tower, continuously distilling off a by-produced dialkyl carbonate from the distillation tower so as to keep the dialkylcarbonate concentration in the reactor at 2% by weight or less, and continuously withdrawing the produced diaryl carbonate and the catalyst from the reactor are disclosed. Continuous production of aromatic carbonates can be performed in a stable manner without being accompanied by clogging of a distillation tower.

Continuous production of aromatic carbonates

Process for producing polyurethane

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Hyogo, Japan

Kiyokazu Murata