Abstract: In the production of acrolein and acrylic acid by the catalytic gas phase oxidation of propylene with a molecular oxygen-containing gas, a method is provided which enables acrolein and acrylic acid to be stably produced with a high yield for a long time from propylene by effectively repressing such secondary reactions as are responsible for the formation of organic acids, high boiling compounds, and tarry compounds, the deposition of carbonized materials, and the deterioration of the quality of products. The content of unsaturated hydrocarbons (excluding propylene) of 2-5 carbon atoms in the raw material for propylene is kept below 500 ppm (by weight). Particularly, it is proper to use a raw material for propylene which has a content of unsaturated hydrocarbons (excluding propylene) of 2-5 carbon atoms of not more than 200 ppm (by weight) and a total content of diene and acetylenic compounds of 2-5 carbon atoms of not more than 200 ppm (by weight).

Abstract: A catalyst for the production of acrylic acid by the vapor-phase catalytic oxidation of acrolein or acrolein-containing gas and a method for the production of acrylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo and V as essential components and used for the production of acrylic acid by vapor-phase catalytic oxidation of acrolein and (B) a solid acid having acid strength (Ho) of not more than −11.93. Since this catalyst excels in catalytic activity and service life, it allows acrylic acid to be produced stably at a high yield for a long time.

Abstract: An apparatus for feeding a granular catalyst to a destination such as a reactor at a constant feeding rate uniformly charges the catalyst material into the device. The granular catalyst is loaded into individual compartments of a hopper and is ejected at a discharge rate controlled by a gate. When a vibrator is activated, a trough is caused to vibrate in its obliquely upward direction and the granular material in the trough is smoothly conveyed toward outlets of granular material passages formed in the trough, and is introduced to reaction tubes of the reactor via sieves. Powdery waste of the granular catalyst produced by the vibration of the trough is removed by letting it fall the sieves made in the granular material passages.

Abstract: A method for producing acrylic acid from propylene at high efficiency by two-stage catalytic oxidation using a single fixed bed shell-and-tube heat exchanger type reactor is provided. The method comprises dividing the shell space of said reactor into an upper space and lower space with a partition plate, allowing a heating medium to circulate in each of the spaces substantially independently of each other, and carrying out the vapor phase oxidation under specific conditions. Said specific conditions including providing a first stage catalyst layer at lower portion of each of the reaction tubes, a second stage catalyst layer at upper portion thereof and an inert substance layer therebetween, and making void ratio of the inert substance layer 40-99.5%.

Abstract: A catalyst for the production of unsaturated aldehyde and unsaturated carboxylic acid by the vapor-phase catalytic oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butanol and methyl-t-butyl ether and a method for the production of unsaturated aldehyde and unsaturated carboxylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo, Bi and Fe as essential components and used for the production of unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene, isobutylene, t-butanol and/or methyl-t-butyl ether and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows unsaturated aldehyde and unsaturated carboxylic acid to be produced stably at a high yield for a long time.

Abstract: Acrylic acid can be produced efficiently by subjecting acrolein to catalytic gas-phase oxidation in the presence of a molybdenum/vanadium-based oxide catalyst prepared by using particular substances as the raw materials of the individual metal elements constituting the catalyst. A preferable example of such a catalyst is prepared by using, as the raw materials of vanadium, ammonium metavanadate and at least one vanadium oxide in which the valency of vanadium is larger than 0 but smaller than 5; as the raw material of copper, copper nitrate; and, as at least part of the raw material(s) of antimony, at least one antimony oxide in which the valency of antimony is larger than 0 but smaller than 5.

Abstract: As an improvement for the process for production of acrylic acid by subjecting acrolein or an acrolein-containing gas to gas-phase oxidation with molecular oxygen in a fixed bed multitubular reactor, there is provided a novel process capable of producing acrylic acid at a high yield by suppressing the generation of heat spots in catalyst or the build-up of heat in hot spots of catalyst. The process comprises filling, in each of reactor tubes, two or more kinds of catalyst particles of different volumes so as to form a plurality of catalyst layers in the axial direction of the tube in such a manner that the particle volume of catalyst layer becomes smaller as the position of catalyst layer changes from the raw material gas inlet side of the tube to the raw material gas outlet side, each catalyst particle comprising, as the active component, a compound oxide containing at least Mo and V.

Abstract: A catalyst for the production of unsaturated aldehyde and unsaturated carboxylic acid by the vapor-phase catalytic oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butanol and methyl-t-butyl ether and a method for the production of unsaturated aldehyde and unsaturated carboxylic acid by the use of this catalyst are provided. The catalyst of this invention comprises (A) a catalyst having Mo, Bi and Fe as essential components and used for the production of unsaturated aldehyde and unsaturated carboxylic acid by vapor-phase catalytic oxidation of propylene, isobutylene, t-butanol and/or methyl-t-butyl ether and (B) a solid acid having acid strength (Ho) of not more than -11.93. Since this catalyst excels in catalytic activity and service life, it allows unsaturated aldehyde and unsaturated carboxylic acid to be produced stably at a high yield for a long time.

Abstract: A process for removal of solid organic matters formed and deposited in the reaction system when an unsaturated aldehyde or an unsaturated aidehyde-containing gas is subjected to catalytic gaseous oxidation in the presence of an oxidizing catalyst to prepare an unsaturated carboxylic acid corresponding thereto, which process comprises contacting the solid organic matters with a mixed gas containing at least 3 volume % of molecular oxygen and at least 0.1 volume % of steam at a temperature of 260.degree. to 450.degree. C.

Abstract: A process for producing an unsaturated aldehyde or an unsaturated acid comprises catalytically oxidizing propylene or at least one compound selected from isobutylene, tert.-butyl alcohol and methyl-tert.-butyl ether in a gaseous phase with molecular oxygen or a molecular oxygen-containing gas using a fixed bed multipipe reactor, wherein(a) a plurality of composite oxides, different in occupied volume, are used as catalyst,(b) a plurality of reaction zones are provided along an axial direction in each reaction pipe of the fixed bed multipipe reactor, and(c) the plurality of the catalysts different in occupied volume are filled in the plurality of the reaction zones such that the occupied volumes become lower from the starting gas inlet side to the outlet side.

Abstract: A method for the production of acrylic acid by the vapor-phase oxidation of acrolein with a molecular oxygen-containing gas in the presence of a catalyst formed of an oxide or a composite oxide of a metal element composition represented by the following formula I:Mo.sub.a V.sub.b W.sub.c Cu.sub.d X.sub.e Y.sub.f (I)wherein X is at least one element selected from the group consisting of Zr, Ti and Ce, Y is at least one element selected from the group consisting of Mg, Ca, Sr and Ba, and the subscripts a, b, c, d, e, and f are such that b=1 to 14, 0<c.ltoreq.12, 0<d.ltoreq.6, 0<e.ltoreq.10, and f=0 to 3 where a is fixed at 12, 2.0<Cu+X.ltoreq.10.0 and 0.25.ltoreq.Cu/X.ltoreq.6.0.

Abstract: A catalyst for use in the production of acrylic acid by catalytic gas phase oxidation of acrolein, comprising active substances represented by general formulaMo.sub.(a) V.sub.(b) A.sub.(c) B.sub.(d) C.sub.(e) D.sub.(f) O.sub.

Abstract: A catalyst used for producing, by catalytic gas phase oxidation of a C.sub.3 -C.sub.5 oelfin or tertiary alcohol, the corresponding unsaturated aldehyde and unsaturated carboxylic acid, said catalyst characterized by comprising molybdenum, iron and bismuth and having a specific surface area in the range from 1 to 20 m.sup.2 /gr, a pore volume in the range from 0.1 to 1.0 cc/gr and a pore diameter distribution in which the pore diameters are collectively distributed in the range of each of from 1 to 10 microns and from 0.1 to less than 1 micron; and a process for preparing said catalyst by charging an unfired material power into a centrifugal flow coating device to form particles having the average particle diameter of 2 to 10 mm and then firing the particles.