Sumitomo Chemical Company, Limited

Katsuyuki Shiota

Kunihiko Tanaka

Yuji Ueda

Hirokazu Hosaka

Toshiharu Morita

Masayoshi Minai

Hiroshi Yamachika

Fujio Masuko

Kenji Tanimoto

Seiichi Kai

Kazuhiko Fujiyoshi

A method for producing 2-cyclopentenones represented by the formula, ##STR1## wherein R represents an alkyl, alkenyl, cycloalkyl, substituted or non-substituted aryl or aralkyl group, which comprises heating 4-cyclopentenones represented by the formula, ##STR2## wherein R has the same meaning as above, in the presence of 1,8-diaza-bicyclo[5,4,0]undecene or its organic acid salt. The 2-cyclopentenones are useful as an intermediate for perfumes, medicines and agricultural chemicals.

Method for producing 2-cyclopentenones

Acetone having a markedly low content of aldehydes is recovered from an aqueous rectification residue brought about by rectification of crude acetone carried out after one crude acetone having been alkali-treated or while an alkali or an aqueous solution thereof being added to the crude acetone, by mixing the aqueous rectification residue with an alkali, neutralizing the mixture to a pH of 4 to 9, and then subjecting the resulting mixture to distillation to obtain acetone as a distillate.

Method for the recovery of acetone

Highly decolorized, purified hydroquinone and resorcinol can be separated from each other from a mixture containing hydroquinone and resorcinol and recovered by continuously rectifying the mixture, thereby obtaining rectification bottoms containing resorcinol and hydroquinone in a ratio by weight of resorcinol to hydroquinone of 0.1-1:1 while obtaining resorcinol as a distillate, redistilling the rectification bottoms, contacting hydroquinone vapor with water vapor, condensing the hydroquinone vapor in the presence of the water vapor, thereby recovering hydroquinone as an aqueous hydroquinone solution, and then recrystallizing the aqueous hydroquinone solution, if necessary, in the presence of an organic solvent, thereby separating hydroquinone from the aqueous solution.

Process for separation and purification of dihydric phenols

An organic quaternary ammonium salt used as a catalyst in a reaction between a benzylnitrile and a halide in the presence of an alkali to obtain an .alpha.-alkyl- or .alpha.-phenyl-benzylnitrile, is recovered effectively from the reaction solution containing the .alpha.-alkyl- or .alpha.-phenyl-benzylnitrile, the alkali and the catalyst, by adding water to the reaction solution to make the alkali concentration of the water layer 10% by weight or below, and then separating the water layer containing the organic quaternary ammonium salt from the oil layer containing the .alpha.-alkyl- or .alpha.-phenyl-benzylnitrile.

Recovery of catalyst

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Toyonaka, Japan

Katsuyuki Shiota