Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Tatsuya Kawabata

Masaaki Okuno

Kenji Ueda

Shinya Tanaka

Tsukasa Takahashi

Yasuhisa Emoto

Masahide Shima

Yasushi Kiyooka

Masafumi Sugio

Toshio Sagane

Chisako Nishio

A catalyst for partial oxidation of olefin, which comprises silver or silver oxide and an alkali metal or a compound thereof supported on an &#x3b1;-alumina carrier containing silicon or a compound thereof, wherein the silicon or the compound thereof exists at a position substantially identical to that of a particle of the alkali metal or the compound thereof, a preparation method thereof, and a process for preparing olefin oxide which comprises subjecting olefin to vapor-phase oxidation with a molecular oxygen-containing gas in the presence of the catalyst.

Catalyst for partial oxidation of olefin, preparation method thereof, and process for preparing alkylene oxide

A catalyst for obtaining pyromellitic anhydride at a high raw material gas concentration with high yield and a method for the production of pyromellitic anhydride are provided. The catalyst containing vanadium and silver as essential component elements for catalyst and having an atomic ratio of silver to vanadium in the range of from 0.001 to 0.2 allows efficient production of pyromellitic anhydride by the vapor-phase oxidation of a tetraalkylbenzene with a molecular oxygen-containing gas. The method of this invention accomplishes the production of pyromellitic anhydride by the use of the catalyst.

Catalyst for production of pyromellitic anhydride and method for

A method for producing efficiently on a commercial scale pyromellitic anhydride having high purity and suffering only sparing coloration in a high yield from a raw material of high concentration is provided. By the use of a multilayer catalyst formed by packing on the reaction gas outlet side a first catalyst containing V and Mo and/or W and having an atomic ratio of Mo and/or W to V in the range of from 0.01 to 2, on the raw material mixed gas inlet side a second catalyst containing V, Mo and/or W and having an atomic ratio of Mo and/or W to V smaller than the atomic ratio of the first catalyst, and/or a third catalyst containing V and an alkali metal and having an atomic ratio of the alkali metal to V in the range of from 0.2 to 2.5, pyromellitic anhydride is produced by the vapor-phase oxidation of a tetraalkyl benzene with a molecular oxygen-containing gas.

Method for production pyromellitic anhydride

The invention relates to a catalyst for producing phthalic anhydride by gas phase catalytic oxidation of o-xylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen and, to a process for producing phthalic anhydride by using said catalyst. The catalyst is made by supporting, on a heat-resistant inorganic carrier, a catalytic active substance which comprises: vanadium oxide; anatase type titanium dioxide having specific surface area of 10 to 60 m.sup.2 /g; niobium; at least one element selected from potassium, cesium, rubidium and thallium; phosphorus; and antimony. The catalytic active substance is prepared by using a five-valent antimony compound as an antimony source. The process for producing phthalic anhydride comprises use of said catalyst.

Catalyst for producing phthalic anhydride and process by using the same

The production of phthalic anhydride by the catalytic vapor-phase oxidation of a mixture of ortho-xylene and naphthalene is accomplished advantageously by a method which comprises packing in a reaction vessel, as a former-stage catalyst, a catalyst produced by supporting on an inactive carrier a catalytic substance composed of vanadium oxide and a specific anatase type titanium dioxide, Nb, P, Sb, and at least one component selected from the group consisting of K, Cs, Rb, and Tl as oxide and, as a latter-stage catalyst, a catalyst similar to the former-stage catalyst excepting the amount of the at least one component selected from among K, Cs, Rb, and Tl is in the range between 17 and 63% by weight as an oxide based on the amount of the same component used in the former-stage catalyst, both in specified bed heights feeding to this reaction vessel the mixture of ortho-xylene and naphthalene and a molecular oxygen-containing gas at a temperature in the range between 300.degree. and 450 .degree. C.

Method for production of phthalic anhydride by vapor-phase oxidation of

The invention presents catalysts for producing phthalic anhydride by vapor phase catalytic oxidation of orthoxylene and/or naphthalene with molecular oxygen or gas containing molecular oxygen. The catalyst is prepared by supporting a catalytic active substance comprising 1 to 20 parts by weight (hereinafter abbreviated 'parts') of vanadium oxide as V.sub.2 O.sub.3, 99 to 80 parts of anatase type titanium dioxide with specific surface area of 10 to 60 m.sup.2 /g as TiO.sub.2 and per 100 parts of the sum of these two ingredients, 0.05 to 1.2 parts of at least one element selected from potassium, cesium, rubidium and thallium as oxide, and 0.05 to 2 parts of silver as Ag.sub.2 O on a heat resistant inorganic carrier. The catalyst may also contain, per 100 parts in total of vanadium oxide and titanium dioxide, 0 to 1 part of niobium as Nb.sub.2 O.sub.5, 0 to 1.2 parts of phosphorus as P.sub.2 O.sub.3, and 0 to 5 parts of antimony as Sb.sub.2 O.sub.3 (however, contents of niobium, phosphorus and antimony will not be zero at the same time).

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Hyogo, Japan

Tatsuya Kawabata