Rare earth perovskite catalysts

Rare earth perovskite catalysts

218 Methane Catalytic Containing Conversion A subject which is gaining more and more interest, following pioneering work and Bhasin in J. reported ...

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218 Methane

Catalytic Containing

Conversion

A subject which is gaining more and more interest, following pioneering work and Bhasin in J. reported by Keller Catalysis (73 (1982) 9) and subsequent papers from the groups of Baerns (see, for example, Proc. Int. Congr. Catal., 3 and T,unsford (see, for (1984) 581) example, J. Amer. Chem. Sot., 107 (1985) coupling of 5062) is the oxidative higher hydrocarbons. methane to give are beginning to More and m"re groups work in this area (including the group which I lead and that of Kees van der the Technica! University of Wiele at Eindhoven) and there is increasing industrial activity. One particularly active industrial laboratory is that of Atlantic Richfield the latest of a series of Co. and organisation have patents to this recently appeared. US Patents 4,499,322 and 4,499,323 claim that catalysts based and On manganese oxide containing praseodymium oxide are effective for the production of mixtures of hydrocarbons. The first of these patents claims containing at one catalysts least oxide of the reducible metals Mn , Sn, In, Ge, Pb, Sb and Bi, preferably Xl, together with at least one promoter such as Na, K or Li, especially Na. The incorporation of P into the catalyst gives a distinct improl-event. With a catalyst containing 7% Na and 10% Mn, supported on silica, the conversion of methane (in a methane-oxvgen mixture) at 800°C was 15.2% and the selectivity to C2 to C, hydrocarbons was 82%. The second patent claims a catalyst formulation based on similar reducible oxides together ;i. i th that of praseodymium (Pr 0 ) and at least one alkali or alka!?iiA earth metal or compound. The catalyst must contain no Ni, Rh, Pd, Ag, OS, Ir, Pt or Au. As an example, a ?iaMnO2!Pr oxide" was prepared by impregnating Pr6011 with sodium permanganate from an aqueous solution. The calcined solids contained 10 ut% of NaMnO~. In an experiment in which methane a one was assed over the f 8 oxidised catalyst at 825 C (and in which the catalyst was subsequently reoxidised by oxygen), a conversion of 80.9% of the methane was obtained with a selectivity to C2 and higher hydrocarbons (including ;;;r-~;ics) of 6.8%. Coke (3.3%) was also

Julian

Ross

applledcatalysls - Volume 23 No. 1 -

May 1986

Combustion

of

Waste

Gases

An article in the Chinese journal, Chemical World (No.5, (1985) 162) presents work carried out at the East China Institute of Chemical Technology, Shanghai, on the catalytic combustion of containing dimethyl ether waste gases ((CH )20). Key to the work is the use of a 2 oneycomb-like catalyst with a non-noble metal constituent. The catalyst is said to exhibit excellent performance in uses such as the treatment of waste gases containing less than 1% of pollutants, the major component (65 - 70%) of which is the ether; the other major components are about 4% of methanol, 2.5 - 3% of acrylonitrile (AS) and 2 - 3% of methyl acrylate (MA). These emitted from are the process of manufacturing MA from AN and MeOH. It is reported that the conversion of Me20 and the residue Me20 were over 98% and less than 400 ppm respectively and that MA and the AN, YeOH contained in the gases were completely eliminated in the catalytic combustion process "using an entrance temperature of and a space 260-E velocity of 20,000 h .

Rare Earth

Perovskitc

Catalysts

Rare earth perovskite catalysts prepared by impregnation have been found to be very active for the conversion of CO to C02: This has been reported in the Chinese Journal, Petroleum Technology (No.6, (1985) 317) by Rong Jing-fang of the Chinese University of Science and Technology. He reported, for example, that a supported catalyst containing 23% of the active compounds was comparable with one containing pure active components which was made by coprecipitation. The effect of the number of impregnations, of the active components and the quantities of support used, of the procedures and conditions of preparation and especially of the properties of the supporting materials on the activities of the rare earth perovskite materials were all studied. Yew Catalyst

for Hydrotreating

An article in the Chinese journal, Petrochemical Processing (No.6, (1985) 16) describes the development and testing of a new catalyst of nomen-