Catalyst, alumina copper chromite

Tlie inlet concentration of H2O2 is 1.18% (w/w), the space-time based on liquid flow is between 60 and 300 s and the gas superficial velocity is 5.5 cm/s. The catalyst is copper chromite on alumina support witli the following chaiacteristics = 1.159 mm,... 

High pressure processes P > 150 atm) are catalyzed by copper chromite catalysts. The most widely used process, however, is the low pressure methanol process that is conducted at 503—523 K, 5—10 MPa (50—100 atm), space velocities of 20, 000-60,000 h , and H2-to-CO ratios of 3. The reaction is catalyzed by a copper—zinc oxide catalyst using promoters such as alumina (31,32). This catalyst is more easily poisoned than the older copper chromite catalysts and requites the use of sulfiir-free synthesis gas. 

Chromia—alumina catalysts are prepared by impregnating T-alumina shapes with a solution of chromic acid, ammonium dichromate, or chromic nitrate, followed by gentie calciaation. Ziac and copper chromites are prepared by coprecipitation and ignition, or by thermal decomposition of ziac or copper chromates, or organic amine complexes thereof. Many catalysts have spiael-like stmctures (239—242). 

Catalyst, alumina, 34, 79 35, 73 ammonium acetate, 31, 25, 27 copper chromite, 31, 32 36, 12 cuprous oxide-silver oxide, 36, 36, 37 ferric nitrate, hydrated, 31, 53 piperidine, 31, 35 piperidine acetate, 31, 57 Raney nickel, 36, 21 sulfuric acid, 34, 26 Catechol, 33, 74 Cetylmalonic acid, 34, 16 Cetylmalonic ester, 34,13 Chlorination, by sulfuryl chloride, 33, 45 ... 

The hydrogenation step talces place in the conventional way in vessel packed with catalyst where the aldehydes and hydrogen are admixed at 200-300°F and 600-1200 psi. The catalyst is usually nickel or copper chromite on an inert carrier such as kieselguhr, silica gel, or alumina. The crude butyl alcohols are finally separated and purified by distillation. 

Catalyst, alumina, 34, 79 35, 73 ammonium acetate, 31, 25, 27 boron trifluoride etherate, 38, 26 copper chromite, 31,32 36, 12 copper powder in quinoline for pyrolytic decarboxylation,... 

Copper chromite tends to catalyze the reduction of the heterocyclic ring and any readily reduced substituents, whereas rhodium on alumina is an effective catalyst for the hydrogenation of the pyrrole ring under very mild conditions (B-77MI30505, B-77MI30507,79CJC1977). 

Dimethylpyrazine. This is produced, in addition to other products, by heating glucose and 25% ammonia at 100 (33), by dehydrogenation (91% yield) of 2,6-dimethylpiperazine over copper chromite at 355-360 (468), and (with other products) from 1,2-propylenediamine and 1,2-propyleneglycol over an alumina catalyst at 400 (394). 

Deactivation during carbon mononide oxidation carried over alumina supported copper and copper-chromite catalysts has been examined. Prereduction of the oxidic precursor with CO increased catalyst activity, but prereduction with hydrogen led to less activity increase due to copper metal crystallization. 

Consequently, the present work has focused to the structural changes accompanying deactivation of copper on alumina catalyst employed for CO oxidation, showing also the effect of the presence of copper-chromite phase on such deactivation. 

Copper Chromite Alumina Catalyst, Kinet. Katal. (1970) 11, 1196. 

Copper-chromite type catalysts supported by alumina or graphite and promoted with barium were used for the one step synthesis of tertiary fatty amines (R2NCH3 or RN(CH3)2) from nitrile, methanol and hydrogen. The surface composition of the catalysts was studied by XPS and by adsorption experiments. A correlation was found between the selectivity and the presence of a well-dispersed CUC1O2 phase, stabilized with barium. Moreover the elements influencing the stability of the copper catalysts were also studied and we remarked the effect of the promoter or/and of the support on the variation of the copper surface area in the presence of water or ammonia. These modifications were examined in relation with the change of the catalytic properties with time-on-stream. 

Hydrogenation is generally carried out at tanperatures of 250-280°C and pressures of 20-25 MPa. Catalysts include zinc oxide in conjunction with aluminum oxide, chromium oxide, or iron oxide, and possibly, other promoters copper chromite whose activity has been reduced by the addition of cadmium compounds and cadmium oxide on an alumina carrier. Selective hydrogenation can also be carried out in a homogenous phase with metallic soaps as catalysts. 

The most active catalysts are derived from supported platinum group metals, or copper chromite when the VOC contains chlorine. The catalyst supports are produced as high surface area gamma-alumina spheres, extmdates or cylindrical pellets that can be used in dust free conditions. Alternatively, when treating large volumes of effluent gas, honeycomb monohths made from cordierite or metal sheets are coated with a surface washcoat of the same alumina are particularly usefiil. The supports are selected to be stable at the operating temperature of the reaction. 

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