Nippon Shokubai Co., Ltd.

Yohji Akazawa

Kazuhiko Sakamoto

Masatoshi Ueoka

Masao Baba

Sei Nakahara

Yoshikuni Mori

Hidefumi Haramaki

Takahiro Takeda

Saburo Nakahara

The present invention provides an improved process for production of acrylic acid by subjecting propylene and/or acrolein to catalytic gas-phase oxidation with a molecular oxygen-containing gas. In the process, the mixed gas obtained by the catalytic gas-phase oxidation is contacted with an aqueous collecting agent containing acrylic acid, acetic acid and a poorly-soluble-in-water solvent, to form an aqueous acrylic acid solution; and the aqueous acrylic acid solution is subjected to azeotropic distillation in the presence of a poorly-soluble-in-water solvent to remove by-products and obtain high-purity acrylic acid.

Process for the production of 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.

Polymerization inhibitor and inhibiting method for vinyl compound

Spherical fine particles of colored resin are provided. The fine particles are of a spherical shape and are superior in heat resistance, solvent resistance, and chemical resistance, and sufficiently satisfactory in durability and coloring, and industrially advantageous. The spherical fine particles of colored resin are made by incorporating an amino resin cured matter and an inorganic pigment into one body, and a ratio of the inorganic pigment against a total amount of the amino resin cured matter and inorganic pigment is in a range of from about 1 to 30% by weight.

Method for producing spherical fine particles of colored resin

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Hyogo, Japan

Yohji Akazawa