Aluminas, as supports

RARE EARTH MODIFIED SILICA-ALUMINAS AS SUPPORTS FOR BIFUNCTIONAL CATALYSIS... 

V-Benzoyl-TV, TV -dialkylthioureas have been prepared under microwave irradiation using potassium fluoride impregnated on alumina as support. Reaction... 

The use of ancillary ligands (imido, alkyUdyne) in alkane metathesis, as well as the improved performance obtained by using alumina or silica-alumina as supports, suggests that other improvements in this field can be envisaged. 

Selective protection of an aldehyde.1 Selective reduction of 4-acetylbenzaldehyde (1) to 4-(l-hydroxyethyl)benzaldehyde (3) is possible by conversion to the sodium bisulfate adduct (2), which is absorbed on silica to increase the stability. The dried adduct is then reduced with diborane. Use of alumina as support is less satisfactory. 

Aluminas are used in various catalytic applications, a-, y-, and -aluminas are all used as support materials, the first one in applications where low surface areas are desired, as in partial oxidation reactions. The latter two, and especially y-alumina, in applications where high surface areas and high thermal and mechanical stability are required. One of the most prominent applications of y-alumina as support is the catalytic converter for pollution control, where an alumina washcoat covers a monolithic support. The washcoat is impregnated with the catalytically active noble metals. Another major application area of high-surface aluminas as support is in the petrochemical industry in hydrotreating plants. Alumina-supported catalysts with Co, Ni, and/or Mo are used for this purpose. Also, all noble metals are available as supported catalysts based on aluminas. Such catalysts are used for hydrogenation reactions or sometimes oxidation reactions. If high... 

One of the directions pursued with ordered mesoporous materials has been changing the framework composition. Many different elements could be incorporated in the walls. Among the numerous variations the all-alumina composition has been of special interest. This is related to the wide spread use of alumina as support in catalysis. Successful syntheses with a neutral and anionic template have been achieved [56], see Table 1. The details will be provided in one of the following presentations [ 56b]. 

The catalyst prepared using a mixture of sepiolite and alumina as support "SACuNi", without doubt led to a pronounced increase in the activity compared... 

With y-alumina, silica and Na-Y zeolite as supports, catalysts derived from [PPN][Ru3Co(CO)i3][ I and other Ru-Co clustersl were studied in the hydrogenation of CO to methane. The formation of CO2 suggested the occurrence of the WGSR and the possibility, at low CO/H2 ratios (1 4), of there being some CO2 methanation. Under these conditions the best yields were obtained with alumina as support. 

Figure 12. Schematic representation of water decomposition using sepiolite and europiunt(III) (A) exchanged alumina as support for [Ru(bipy)3] " (D) (reproduced from ref. 323)...

Souza MVM, Schmal M. Surface characterization of zirctmia-coated alumina as support for Pt particles. Phys Status Solidi A. 2001 187 297-303. 

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