Mitsubishi Chemical Corporation

Mitsubishi Kasei Corporation

Yu Kanda

Toshio Uchibori

Takeshi Ishikawa

Akio Tsuboi

Kouji Teramoto

Haruo Habu

Takeshi Matsuoka

Makoto Tezuka

Hidefumi Sano

Tsutomu Yonemori

The present invention provides a method for producing .epsilon.-caprolactam, which comprises subjecting cyclohexene to a hydration reaction to obtain cyclohexanol, subjecting the cyclohexanol to a dehydrogenation reaction to obtain cyclohexanone, subjecting the cyclohexanone to an oxime-forming reaction to obtain cyclohexanone oxime, and subjecting the cyclohexanone oxime to a Beckmann rearrangement reaction to obtain .epsilon.-caprolactam, wherein methylcyclopentanones contained in the cyclohexanone subjected to the oxime-forming reaction are controlled to be not more than 400 ppm. According to the present invention, it is possible to produce .epsilon.-caprolactam having a quality not inferior to conventional quality at a low cost.

Process for the preparation of .epsilon.-caprolactam

Cyclohexene is separated from a mixture of cyclohexene and at least one of cyclohexane and benzene by subjecting the mixture to extractive distillation in the presence of an extraction solvent the formula: ##STR1## wherein R.sup.1 and R.sup.2 each is a C.sub.1-10 alkyl group or hydrogen, and n is an integer of from 2-4, thereby preparing a fraction rich in cyclohexene.

Method for separating cyclohexene

A method for preparing an oxime, which comprises partitioning an aqueous hydroxylamine salt solution phase and a ketone or aldehyde phase by a cation exchange membrane, and permitting hydroxylamine in the aqueous hydroxylamine salt solution phase to diffuse and transfer through the membrane to the ketone or aldehyde phase and to form an oxime in the ketone or aldehyde phase.

Method for preparing an oxime

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Kitakyushu, Japan

Yu Kanda