Nippon Shokubai Co., Ltd.

Tadayoshi Kawashima

Tetsuya Kajihara

Yasuhiro Shingai

Tokumasa Ishida

Yoshitake Ishii

Yukihiro Yoneda

Masahiro Uemura

Hideaki Nagano

Kei Hamamoto

Sumio Nakashima

Kaoru Iwasaki

Souichi Yamada

This invention discloses a method for producing maleic anhydride comprising an azeotropic distillation step to dehydrate a crude maleic acid-containing aqueous solution, which method is characterized by as an azeotropic solvent (1) using an organic solvent exhibiting a maximum dissolving concentration of the organic solvent in water in the range of 0.1-5% by weight at a temperature of 20&#xb0; C. According to this invention, it is made possible to prevent the occurrence of a blocking substance, allow a continuous operation for a long time, and remove by-produced acid components by a process of distillation for azeotropic dehydration.

Method for production of maleic anhydride

The present invention provides: a production process for a hydroxyalkyl(meth)acrylate, which can raise productivity together with avoiding danger of explosion, and further can suppress side-formation of impurities such as a diester or a monoester wherein the impurities have a bad influence on product quality. When the time from the start of adding an alkylene oxide (AO) till the end of supplying the entirety of the AO is defined as T (hour), the amount of more than 50% of the entirety of the AO is supplied before T/2 (hour) has passed since the start of adding the AO. In addition, when the total amount of an AO as supplied and the time from the start of adding the AO till the end of supplying the entirety of the AO are defined as W (mol) and T (hour) respectively, the supply of the AO is started at a supplying speed V0 (mol/hour) that is faster than the average supplying speed V (&equals;W/T) (mol/hour), and thereafter the supplying speed of the AO is decreased at least once, and then the supply of the entirety of the AO is completed for T (hour) from the start of adding the AO.

Production process for hydroxyalkyl (meth)acrylate

In the operation of producing an alkylamino(meth)acrylate by the reaction of transesterification of an alkyl(meth)acrylate with an alkylamino alcohol, the alkyl alcohol by-produced during the transesterification is distilled in the form of an azeotropic mixture with the alkyl(meth)acrylate, the resultant distillate is purified with an ion-exchange resin and handled, on the other hand, the reaction solution is distilled to allow separation of the catalyst wherein is provided a method and apparatus for effecting, in the production of the alkylamino(meth)acrylate, the distillation under such a condition as represses the amount of in crease of the Michael adduct below 2%.

Method for production of alkylamino(Meth)acrylate and apparatus therefor

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Himeji, Japan

Tadayoshi Kawashima