Nippon Shokubai Co., Ltd.

Hidefumi Haramaki

Takeshi Nishimura

Kazuhiko Sakamoto

Osamu Dodo

Tetsuji Mitsumoto

Yukihiro Matsumoto

Sei Nakahara

Masatoshi Ueoka

Masao Baba

Mamoru Takamura

Takehiro Takashima

Yohji Akazawa

Yousuke Ogata

Manabu Matsui

A process for producing an acrylic ester using acrylic acid and an aliphatic or alicyclic alcohol having from 5 to 8 carbon atoms, as raw materials, and using a strongly acidic cation exchange resin as a catalyst. In such a process for producing an acrylic ester, a crude acrylic ester withdrawn from the bottom of a low-boiling separation column is supplied to a rectifying column, a rectified acrylic ester is taken out from the top of the rectifying column, while a high-boiling substance containing an acrylic ester, which is withdrawn from the bottom of the rectifying column, is supplied to a high-boiling separation column and/or a thin-film evaporator to separate it into an acrylic ester component and a high-boiling substance, and the separated acrylic ester component is taken out as a distillate and supplied to the low-boiling separation column for its recovery.

Process for producing acrylic ester

This invention resides in providing a method for the prevention of possible polymerization of the easily polymerizable substance during the purification thereof by a column provided with (a) at least one tray directly fixed to a support ring with a bolt and a nut and/or (b) at least one tray fixed to a support ring with a vertical clamp or a distillation column provided in the lower part thereof with a splash collision plate.

Method for production of easily polymerizable substance and purification apparatus

A method for producing an organic acid and/or an organic acid ester which utilizes a steam system permitting stable production of an organic acid and/or an organic acid ester and realizing a high thermal efficiency constantly relative to the waste heat generated in the process of the production is provided. More particularly, this invention concerns a method for the production of an organic acid and/or an organic acid ester, wherein heat generated in the process for producing an organic acid and/or an organic acid ester is recovered in the form of steam, and the steam is used in any of the following forms: {circle around (1)} thermal energy, {circle around (2)} dynamic energy, and {circle around (3)} electrical energy in the process for producing an organic acid and/or an organic acid ester.

Method for production of organic acid

A shell-and-tube reactor has a plurality of reaction tubes incorporated therein, a circulation path for the heating medium formed outside the reaction tubes, a heating medium introducing section provided on the upper part of the shell in the reactor and a heating medium discharge section provided on the lower part of the shell in the reactor, a back pressure applying means for the heating medium is further provided in the heating medium discharge section.

Shell-and-tube reactor

In a method for producing acrylic acid by the steps of a reaction of catalytic gas phase oxidation, absorbing the acrylic acid with an absorbent, and dehydrating the acrylic acid-containing aqueous solution, the method is characterized that the step of dehydration comprises adding and an azeotropic solvent, distilling the resultant mixture, and adjusting the acrylic acid concentration at the top of the column in the range of 0.06-0.80 wt. %, thereby preventing the bottoms of the azeotropic dehydration column from substantially containing the azeotropic solvent and water. As results, the acrylic acid is kept from forming a polymer in any of the distillation columns involved in the production, and effective utilization of acrylic acid.

Method for production of acrylic acid

The present invention provides a process for producing (meth)acrylic acid by gas-phase catalytic oxidation, which comprises cooling and condensing a (meth)acrylic acid-containing reaction product gas to obtain a crude aqueous (meth)acrylic acid solution; cooling the aqueous solution to deposit the impurities contained in the aqueous solution, as solid matter; separating the solid matter; and then extracting and separating (meth)acrylic acid from the purified aqueous (meth)acrylic acid solution obtained. Unlike the conventional processes in which (meth)acrylic acid is extracted and separated from a crude aqueous (meth)acrylic acid solution, the present process can avoid various troubles caused by the impurities contained in the crude aqueous (meth)acrylic acid solution, for example, generation of scum and the like, and therefore can produce (meth)acrylic acid at a higher purity than in the conventional processes.

Process for producing (meth) acrylic acid

This invention is directed to a polymerization inhibitor and a polymerization inhibiting method which enables the continuous operation of a device for producing vinyl compounds over a long period of time and virtually eliminates corrosion. Further, the polymerization inhibitors according to the present invention are superior in polymerization inhibition when transferring and storing the vinyl compound products and in other cases. The polymerization inhibitor according to the present invention contains manganese dithiocarbamate or a thiuram compound as an effective component. The polymerization inhibiting method of this invention comprises individual or joint use of said inhibitors, or joint use of a copper salt, another manganese salt, or quinones in addition to said inhibitors. Further, the method may comprise jointly using copper dithiocarbamates in a manganese salt as polymerization inhibitors, or jointly using quinones in addition to the salts.

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Himeji, Japan

Hidefumi Haramaki