Abstract: A heteropoly-acid of the formula:H.sub.3+x (PMo.sub.12-x V.sub.x O.sub.40).nH.sub.2 Owherein x and n are numbers satisfying respectively the equations: 0.ltoreq.x.ltoreq.3 and n.ltoreq.6, and comprising phosphorus as the central atom and molybdenum or molybdenum and vanadium as the coordinating atoms, or its reduction-form product, which is in a cubic crystal structure having diffraction lines at lattice spacings (d) of at least 8.4, 6.8, 5.9, 4.8, 4.2 and 3.4 in the X-ray powder diffraction. The heteropoly-acid is useful as a catalyst, especially as a catalyst in the production of methacrylic acid by the gas-phase catalytic oxidation of methacrolein.

Abstract: In the production of methacrolein by vapor phase catalytic oxidation of isobutylene and/or t-butyl alcohol, an improved process for suppressing the amount of acetone to be by-produced which comprises contacting a gaseous mixture comprising isobutylene or t-butyl alcohol, molecular oxygen and steam with a metal oxide catalyst composition comprising molybdenum and bismuth as the essential metal components, the amount of steam in the gaseous mixture being kept to be not more than 4 mol per mol of isobutylene or not more than 3 mol per mol of t-butyl alcohol.

Abstract: In the production of acrylonitrile by a vapor phase reaction of propylene, ammonia and oxygen at an elevated temperature, a process which comprises contacting propylene, ammonia and oxygen with a catalyst composition comprising a catalyst system of the formula: Tl.sub.a P.sub.b Mo.sub.c Fe.sub.d Bi.sub.e X.sub.f O.sub.g wherein X represents one or more of the metals, Ni, Mg and Co, and a, b, c, d, e, f and g represent respectively the relative number of atoms of each component; provided that when c is 12, a is 2 or less, but not 0; b is 0 to 5; d is 0.1 to 5; e is 0.1 to 5; f is 2 to 15; and the value of g depends on the number of the other atoms and is usually from 38.3 to 81.5.

Abstract: A process for the selective removal of nitrogen oxides from waste gases containing nitrogen oxides, which comprises contacting the waste gases with a metal oxide catalyst having the following formula:V.sub.x A.sub.y O.sub.zwherein V is vanadium; A is at least one element selected from the group consisting of copper, zinc, tin, lead, titanium, phosphorus, chromium, iron, cobalt and nickel; x and y are each a numeral of 0.5 to 12; and z is a numeral of 1 to 60, at a temperature of 150.degree. to 800.degree. C in the presence of ammonia.

Abstract: A method for treating ammonia-containing gases for removing ammonia therefrom, which comprises contacting the ammonia-containing gases with a metal oxide catalyst having the following formula:Cr.sub.x A.sub.y O.sub.zwherein Cr is chromium; A is at least one element selected from the group consisting of tin, antimony, vanadium, cobalt, silver, zinc, nickel, titanium, molybdenum, tungsten, sulfur, phosphorus, boron, germanium and zirconium; x is a numeral of 4 to 12; y is a numeral of 0.2 to 8 and z is a numeral of 6.2 to 42, in a vapor phase at a temperature of from 200.degree. to 500.degree. C in the presence of molecular oxygen, and thereby the ammonia is oxidized to harmless nitrogen gas.

Abstract: A catalytic process for the preparation of acrolein by the vapor phase oxidation of propylene which comprises contacting propylene and oxygen with a catalyst composition comprising a catalyst system of the formula:Mo.sub.a Bi.sub.b Fe.sub.c X.sub.d Ni.sub.e Tl.sub.f P.sub.g O.sub.hwherein X is one or more of Mg, Mn and Co and a, b, c, d, e, f, g and h represent, respectively, the number of atoms wherein a is 12, b is 0.1 to 5, c is 0.1 to 5, d is 0 to 12, e is 0.1 to 12, f is 1 or less but not 0, g is 0 to 5 and h depends on the number of the other atoms and is usually from 36 to 89. Acrolein is produced with the use of said catalyst in a high selectivity and an excellent yield per each pass even at a large space velocity.

Abstract: A process for the preparation of acrolein by the vapor phase catalytic oxidation of propylene which comprises contacting propylene and oxygen with a catalyst composition comprising a catalyst system of the formula:Mo.sub.a Bi.sub.b Fe.sub.c Ni.sub.d Tl.sub.e P.sub.f X.sub.g Y.sub.h O.sub.iWherein X is one or more of Mg, Mn and Co, Y is one or more of Cu, Ca, Sr, Zn, Cd, Sn and Pb and a, b, c, d, e, f, g, h and i represent respectively the number of atoms and, when a is 12, b is 0.1 to 5, c is 0.1 to 12, d is 0.1 to 12, e is 1 or less but not 0, f is 0 to 5, g is 0 to 12, h is 0.1 to 12 and i is a number determined by the valence requirements of the other atoms present and from 36.5 to 95.8, provided that b plus c is from 0.2 to 12.5 and d plus g plus h is from 0.2 to 27. The process can provide acrolein in a high selectivity and an excellent single pass yield even at a large space velocity of the propylene feed.

Abstract: A catalytic process for the preparation of acrolein by the vapor phase oxidation of propylene which comprises contacting propylene and oxygen with a catalyst composition comprising a catalyst system of the formula:Mo.sub.a Bi.sub.b Fe.sub.c Ni.sub.d Tl.sub.e P.sub.f X.sub.g Y.sub.h O.sub.i wherein X is one or more of Mg, Mn and Co, Y is one or more of Cu, Ca, Sr, Zn, Cd, Sn and Pb and a, b, c, d, e, f, g, h and i represent respectively the number of atoms, provided that, when a is 12, b is 0.1 to 5, c is 0.1 to 12, d is 0.1 to 12, e is 1 or less but not 0, f is 0 to 5, g is 0 to 12, h is 0.1 to 12 and i is from 36 to 112. By such a process, acrolein is produced in a high selectivity and an excellent yield per each pass even at a large space velocity.