Dystar Japan Ltd.

Shinji Kubo

Kiyoshi Himeno

Toshio Hihara

Yoshiharu Hamano

A process for producing a monoazodye of the following formula (III): ##STR1## wherein X.sup.1 is nitro or halogen, X.sup.2 is halogen, R.sup.1 is lower alkoxy, R.sup.2 is lower alkyl, each of R.sup.3 and R.sup.4, which are independent of each other, is alkyl, cyanoalkyl or alkylcarbonyloxyalkyl, and each of m and n, which are independent of each other, is 0 or 1, which comprises diazotizing an aniline derivative of the following formula (I): ##STR2## wherein X.sup.1 and X.sup.2 are as defined above, followed by coupling with an aniline derivative of the following formula (II): ##STR3## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, m and n are as defined above, wherein a reaction mixture obtained by the coupling reaction is heat-treated in the presence of a polyoxyethylene higher fatty acid ester type nonionic surfactant, followed by filtration to obtain said monoazo compound in the form of a cake.

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Nakama, Japan

Shinji Kubo