Patent GB-989728-A (GB)
Title: Catalyst for oxidizing organic combustible constituents and carbon monoxide in exhaust gases of internal combustion engines and industrial waste gases
IPC: B01J23/00
Filed: 1961-07-26
Abstract: A catalyst for oxidizing organic combustible constituents and carbon monoxide in exhaust gases of internal combustion engines and industrial waste gases is prepared by impregnating an inorganic oxide carrier containing at least a major proportion of alumina and having an apparent bulk density (defined) of less than 0.4 grams/c.c. with an aqueous solution of a compound of a metal, said metal having catalytic oxidizing activity, drying the composite at a temperature below 260 DEG  C. without substantial oxidation thereof and then subjecting the dried composite, before contact with any mixture of air and exhaust or waste gas, to treatment with hydrogen or a gaseous hydrogen-hydrocarbon mixture at 95 DEG -980 DEG  C. said metal compound being reduced to metal having catalystic oxidizing activity. The metal may be: V, Cr, Mo, W, Fe, Co, Ni, Cu, Pd, Rh, Ru, Ir, Os, Ag, Au and Pt or mixtures, e.g. Pt-Fe, Pt-Co, Pt-Ni, Pd-Fe, Pd-Co, Pd-Ni, Pt-Pd, Pd-Cu-Co, Pt-Co-Cu-Li, Pt-Co-Cu, Cu-Co-Ni-Pt, Pt-Pd-Co, Mg-Pt, Pt-Co-Mg, Li-Pt-Co and Cu-Co-Li. Water soluble compounds of these metals are nitrates, sulphates, chlorates, chlorides and carbonates.  The alumina may also contain 0.5-20% of TiO2, HfO2, ZrO2 or a mixture of these.  The alumina may be precipitated from AlCl3 solution washed, dried, calcined in air and the Al2O3 particles, mixed with a solution of a Pt compound in amount so that the catalyst contains 0.01 to 5% of Pt.  The density of the Al2O3 may be controlled by keeping the Al to chloride weight ratio above 1.3 during the preparation of the Al2O3 hydrosol, or by ageing by subjecting to pressure sufficient to maintain water in the liquid phase at 99 DEG  C. Phosphorus or a halogen may be combined with the support either before or after the incorporation of the catalytic alloy active metal, e.g. by the use of HF, HCl or NH4F or NH4Cl. Specification 693,648 is referred to.ALSO:A catalyst for oxidizing organic combustible constituents and carbon monoxide in exhaust gases of internal combustion engines and industrial waste gases is prepared by impregnating an inorganic oxide carrier containing at least a major proportion of alumina and having an apparent bulk density (defined) of less than 0,4 grams/c.c. with an aqueous solution of a compound of a metal, said metal having catalytic oxidizing activity, drying the composite at a temperature below 260  DEG C. without substantial oxidation thereof and then subjecting the dried composite, before contact with any mixture of air and exhaust of waste gas, to treatment with hydrogen or a gaseous hydrogen-hydrocarbon mixture at 95-980  DEG C., said metal compound being reduced to metal having catalytic oxidizing activity.  The metal may be: V, Cr, Mo, W, Fe, Co, Ni, Cu, Pd, Rh, Ru, Ir, Os, Ag, Au and Pt or mixtures e.g. Pt-Fe, Pt-Co, Pt-Ni, Pd-Fe, Pd-Co, Pd-Ni, Pt-Pd, Pd-Cu-Co, Pt-Co-Cu-Li, Pt-Co-Cu, Cu-Co-Ni-Pt, Pt-Pd-Co, Mg-Pt, Pt-Co-Mg, Li-Pt-Co and Cu-Co-Li.  Water soluble compounds of these metals are nitrates, sulphates, chlorates, chlorides and carbonates. The alumina may also contain 0,5-20% of TiO2, HfO2, ZrO2 or a mixture of these.  The alumina may be precipitated from AlCl3 solution, washed, dried, calcined in aid and the Al2O3 particles, mixed with a solution of a Pt compound in amount so that the catalyst contains 0,01-5% of Pt.  The density of the Al2O3 may be controlled by keeping the Al to chloride weight ratio above 1,3 during the preparation of the Al2O3 hydrosol, or by ageing by subjecting to pressure sufficient to maintain water in the liquid phase at 99  DEG C.  Phosphorus or a halogen may be combined with the support either before or after the incorporation of the catalytically active metal e.g. by the use of HF, HCl or NH4F or NH4Cl.  Specification 693,648 is referred to.