Catalysts aluminas

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 ... 

Catalyst alumina from aluminum isopropoxide with piperidine. 2-B = 2-butanol 2-P = 2-pentanol 3-P = 3-pentanol. 

Temperature, 275" catalyst, alumina from aluminum isopropoxide with piperidine. 

This paper identifies alumina, rare earths, platinum, and magnesia as important SOx capture materials. Alumina is either incorporated directly into the matrix of a cracking catalyst or added as a separate particle. Cerium is shown to promote the capture of SO2 on high alumina cracking catalyst, alumina, and magnesia. Other rare earths are ranked by their effectiveness. The promotional effect of platinum is shown between 1200 and 1400 F for SO2 capture on alumina. Silica, from free silica or silica-alumina in the matrix of cracking catalyst, acts as a poison by migrating to the additive. 

Rare earths have also been included as desirable SOx catalyst components in early patents but the catalytic behavior of cerium, in particular, had not been clarified. This paper has presented evidence that cerium catalyzes the oxidative adsorption of SO2 on high alumina cracking catalyst, alumina, and magnesia. We also have shown the catalytic character of platinum. The details of the catalysis especially by cerium, however, remain unexplained. 

The same authors (77) also investigated the Michael addition of nitromethane to a,/l-unsaturated carbonyl compounds such as methyl crotonate, 3-buten-2-one, 2-cyclohexen-l-one, and crotonaldehyde in the presence of various solid base catalysts (alumina-supported potassium fluoride and hydroxide, alkaline earth metal oxides, and lanthanum oxide). The reactions were carried out at 273 or 323 K the results show that SrO, BaO, and La203 exhibited practically no activity for any Michael additions, whereas MgO and CaO exhibited no activity for the reaction of methyl crotonate and 3-buten-2-one, but low activities for 2-cyclohexen-l-one and crotonaldehyde. The most active catalysts were KF/alumina and KOH/alumina for all of the Michael additions tested. 

Both alumina and silica gel are more stable physically than the common polystyrene supports. The alumina-bound catalysts are particularly promising because of their higher activity and higher selectivity compared with the silica gel-bound catalysts. Alumina also is stable in alkali. The alumina-bound catalysts 32 and 33 worked well for reaction of 1-bromooctane with concentrated aqueous sodium cyanide 118). 

Support for NO oxidation reaction was reported that Si02 seemed to be preferable (Xue et al., 1996). However, NSR catalysts are subjected high thermal stability like as the conventional automotive catalyst. Alumina supports is popular for the catalyst for its high thermal durability with a high surface area. Some other supports have been developed for improving SOx durability as described later. 

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,... 

In nonalkylation systems, such as the classic heterogeneous catalysts [alumina-supported M0O3, Re207, and WtCOtg] or combinations such as WC16 + AICI3, the carbene must come from the alkene, which is a more difficult problem to explain. 

All these results are easily explained on the basis of structural properties of samples provided by X ray and EPR studies. It was actually pointed out that for low contents of chromium in the catalysts, alumina interacts with the amorphous active phase and favours the stabilization of low coordinate chromium ions... 

Caro s acid, 22, 44, 74 Carvacrylamine, 22, 9 Catalyst, alumina, 22, 40 boron trifluoride, 20, 6 copper bronze, 20, 45 copper-chromium oxide for decarboxylation, 22, 67... 

Figure 4 Representation of the three components of a typical HDS catalyst (alumina, M0S2, and cobalt promoter) and the spatial relation between them.

The dehydration reaction is performed over a suitable sold acid catalyst (alumina or silica-alumina) at typically 250°C. The equiUbrium is established and the products separated from any unconverted ethanol by distillation. The ethanol is recycled Figure 10.9. 

Various catalysts used in the two processes have been described as follows zeolite, alumina, silica-alumina, FCC catalyst, reforming catalyst, and others. The most common catalysts used in the cracking of heavy hydrocarbons are acidic catalysts alumina and silica-alumina with mesopores, and also zeolite with micropores, etc. They are typically used in the commercial petroleum process. For the chemical properties of catalyst, the... 

The lower quantification limit of platinum in a reforming catalyst (alumina support) is 5 ppm. 

The traditional catalysts have usually a short period of operation because of high rates of deactivation processes, such as polymerization, carbonization, and decomposition of the active component. The catalysts are routinely prepared by precipitation, which results in formation of a wide range of surface species, providing a number of side reactions. The side reactions may also occur on alumina, the main support for the hydrogenolysis catalysts. Alumina is an active catalyst for dehydration processes as well ... 

---