Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Hideto Hashiba

Yukio Aoki

Ikuo Kurimoto

Akiyoshi Nakajima

Michio Tanimoto

Hideo Onodera

Shigeru Ohno

Shinichi Higashi

Osamu Takayasu

The present invention provides: a fixed-bed shell-and-tube reactor, which can stably produce an aimed product for a long period when a solid particulate material such as a catalyst is packed and used for each substance; and its usage. The fixed-bed shell-and-tube reactor comprises a plurality of reaction tubes that are packed with a solid particulate material and arranged in parallel, wherein the solid particulate material is weighed so as to be uniform volume, and is packed in each reaction tube in a packing time of not shorter than 30 seconds per liter.

Fixed-bed shell-and-tube reactor and its usage

In the production of maleic anhydride by the contact of a raw material gas containing an aliphatic hydrocarbon of not less than 4 carbon atoms and molecular oxygen with a vanadium-phosphorus oxide catalyst, the raw material gas is caused to allow presence therein of nitrogen and an inert gas possessing a thermal conductivity of not less than 800 (10,Wm,K,) at 700 K. The gas formed by the oxidation reaction is allowed to contact an absorbent to effect recovery of the produced maleic anhydride. Maleic anhydride is recovered from produced oxidation reaction gas separated from a remained oxidation reaction gas after recovering maleic anhydride, and the saparated inert gas is circulated to the reaction zone. The catalyst capable of producing maleic anhydride with a high yield can be obtained by activating the vanadium-phosphorus oxide catalyst with the gas composition containing an inert gas possessing a thermal conductivity of not less than 800 (10,Wm,K,) at 700 K.

Method for production of maleic anhydride

A vanadium-phosphorus oxide having an X-ray diffraction spectrum (Cu--K.alpha.) showing main peaks of the diffraction angle 2.theta.(.+-.0.2.degree.) at 18.5.degree., 23.0.degree., 28.4.degree., 29.9.degree., and 43.1.degree. and having the intensity ratio of the peaks of the diffraction angle 2.theta.(.+-.0.2.degree.) at 23.0.degree. and 28.4.degree. in the following range

Method of preparing maleic anhydride by vapor phase oxidation of

A process for producing methacrylic acid, which comprises

Process for producing methacrylic acid

A catalyst for the production of methacrylic acid composed of an inert carrier and a catalytically active substance. The catalytically active substance layer being composed of oxides represented by the following formula (I)

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Himeji, Japan

Hideto Hashiba