Calcium oxide catalyst

Certain amines are readily prepared by the reduction of aromatic, aryl aliphatic, and heterocyclic amines. For example, aniline is reduced to cyclohexylamine by high-pressure hydrogenation in the presence of Raney nickel catalyst or a cobalt oxide-calcium oxide catalyst. The reaction occurs at a temperature above 200°, where condensation of the primary amine also takes place, viz., 2CjHiiNHj — (CjHn),NH + NH,. If this side reaction is repressed by the presence of dicyclohexylamine at the start of the reaction, a 94% yield of cyclohexylamine is obtained. Hydrogenation of aryl aliphatic amines proceeds more readily, occurring at moderate temperatures and pressures over platinum catalyst in glacial acetic acid. Other reductions using this catalyst are best performed on the amines in the form of their hydrochlorides. ... 

A large number of basic catalysts such as the metal oxides like PbO, ZnO, CaO, NaOMe and NaOEt, and hydroxides like LiOH, Ca(OH)2, and KOH are used in the preparation of poly(ester amide) resins. Alkaline metal (Li, Na, K)-doped calcium oxide catalysts are effective in transesterification of this resin. A few enzymes can also be used as the catalysts for the preparation of poly(ester amide) resins. 

Ji, L. and Liu, J. Excellent promotion hy lithium of a lanthanum-calcium oxide catalyst for oxidative dehydrogenation of ethane to ethane. Ghent. Contntun. 1996,10,1203. 

Less activated substrates such as uorohaloben2enes also undergo nucleophilic displacement and thereby permit entry to other useful compounds. Bromine is preferentially displaced in -bromofluoroben2ene [460-00-4] by hydroxyl ion under the following conditions calcium hydroxide, water, cuprous oxide catalyst, 250°C, 3.46 MPa (500 psi), to give -fluorophenol [371-41-5] in 79% yield (162,163). This product is a key precursor to sorbinil, an en2yme inhibitor (aldose reductase). 

In the vapor phase, acetone vapor is passed over a catalyst bed of magnesium aluminate (206), 2iac oxide—bismuth oxide (207), calcium oxide (208), lithium or 2iac-doped mixed magnesia—alumina (209), calcium on alumina (210), or basic mixed-metal oxide catalysts (211—214). Temperatures ranging... 

In the presence of a potassium catalyst dispersed on calcium oxide, toluene reacts with 1,3-butadiene to yield 5-phenyl-2-pentane (22). 

Salts of neodecanoic acid have been used in the preparation of supported catalysts, such as silver neodecanoate for the preparation of ethylene oxide catalysts (119), and the nickel soap in the preparation of a hydrogenation catalyst (120). Metal neodecanoates, such as magnesium, lead, calcium, and zinc, are used to improve the adherence of plasticized poly(vinyl butyral) sheet to safety glass in car windshields (121). Platinum complexes using neodecanoic acid have been studied for antitumor activity (122). Neodecanoic acid and its esters are used in cosmetics as emoUients, emulsifiers, and solubilizers (77,123,124). Zinc or copper salts of neoacids are used as preservatives for wood (125). 

The industrial catalysts for ammonia synthesis consist of far more than the catalyticaHy active iron (74). There are textural promoters, alumina and calcium oxide, that minimise sintering of the iron and a chemical promoter, potassium (about 1 wt % of the catalyst), and possibly present as K2O the potassium is beheved to be present on the iron surface and to donate electrons to the iron, increasing its activity for the dissociative adsorption of N2. The primary iron particles are about 30 nm in size, and the surface area is about 15 m /g. These catalysts last for years. 

Over the years, HteraHy thousands of catalyst formulations have been evaluated and those available today are significantly more active, which has allowed considerable improvement in productivity and plant operation. Today, a typical catalyst contains approximately 93 wt % Fe O, and about 1 wt % potassium oxide, 3 wt % alumina, 3 wt % calcium oxide, and 0.5 wt % siHca, which is actually an unnecessary impurity. 

Ethyl chloride can be dehydrochlorinated to ethylene using alcohoHc potash. Condensation of alcohol with ethyl chloride in this reaction also produces some diethyl ether. Heating to 625°C and subsequent contact with calcium oxide and water at 400—450°C gives ethyl alcohol as the chief product of decomposition. Ethyl chloride yields butane, ethylene, water, and a soHd of unknown composition when heated with metallic magnesium for about six hours in a sealed tube. Ethyl chloride forms regular crystals of a hydrate with water at 0°C (5). Dry ethyl chloride can be used in contact with most common metals in the absence of air up to 200°C. Its oxidation and hydrolysis are slow at ordinary temperatures. Ethyl chloride yields ethyl alcohol, acetaldehyde, and some ethylene in the presence of steam with various catalysts, eg, titanium dioxide and barium chloride. 

Cobalt. Without a doubt cobalt 2-ethyIhexanoate [136-52-7] is the most important and most widely used drying metal soap. Cobalt is primarily an oxidation catalyst and as such acts as a surface or top drier. Cobalt is a transition metal which can exist in two valence states. Although it has a red-violet color, when used at the proper concentration it contributes very Httie color to clear varnishes or white pigmented systems. Used alone, it may have a tendency to cause surface wrinkling therefore, to provide uniform drying, cobalt is generally used in combination with other metals, such as manganese, zirconium, lead, calcium, and combinations of these metals. 

The production of synthesis gas from natural gas and coal is the basis of the 33 000000 tpa methanol production and is also used in the production of ammonia. After removal of sulfur impurities, methane and water are reacted over a nickel oxide on calcium aluminate catalyst at 730 °C and 30 bar pressure. The reaction is highly endothermic (210 kJmol ) (Equation 6.6). 

Figure 17.6 illustrates a gasification process integrated with the calcium looping process. Once the water gas mixture is formed at the exit of the gasifier, calcium oxide fines are injected into the fuel gas stream. As the fuel gas flows past the WGS catalyst, the WGS reaction takes place and forms additional C02. The injected CaO sorbent particles react with C02 and H2S in the gas stream, thereby allowing further catalytic WGS reaction to occur. The reactions involved in the calcium looping scheme are... 

Ding and Alpay also studied sorption-enhanced reforming with K-HTC as sorbent [28], using a commercial Ni-based catalyst. They found that the SER process benefits from higher pressures and that lower steam to methane ratios can be used than in ordinary reforming. Reijers et al. [25] have shown that K-HTC is an effective sorbent between 400 and 500 °C, with an C02 uptake of approx. 0.2 mmol g 1. This capacity is low compared with calcium oxides and lithium zirconates. Above 500 °C, the C02 sorption capacity of K-HTC decreases rapidly to zero [36]. 

Peterson and Scarrah 165) reported the transesterification of rapeseed oil by methanol in the presence of alkaline earth metal oxides and alkali metal carbonates at 333-336 K. They found that although MgO was not active for the transesterification reaction, CaO showed activity, which was enhanced by the addition of MgO. In contrast, Leclercq et al. 166) showed that the methanolysis of rapeseed oil could be carried out with MgO, although its activity depends strongly on the pretreatment temperature of this oxide. Thus, with MgO pre-treated at 823 K and a methanol to oil molar ratio of 75 at methanol reflux, a conversion of 37% with 97% selectivity to methyl esters was achieved after 1 h in a batch reactor. The authors 166) showed that the order of activity was Ba(OH)2 > MgO > NaCsX zeolite >MgAl mixed oxide. With the most active catalyst (Ba(OH)2), 81% oil conversion, with 97% selectivity to methyl esters after 1 h in a batch reactor was achieved. Gryglewicz 167) also showed that the transesterification of rapeseed oil with methanol could be catalyzed effectively by basic alkaline earth metal compounds such as calcium oxide, calcium methoxide, and barium hydroxide. Barium hydroxide was the most active catalyst, giving conversions of 75% after 30 min in a batch reactor. Calcium methoxide showed an intermediate activity, and CaO was the least active catalyst nevertheless, 95% conversion could be achieved after 2.5 h in a batch reactor. MgO and Ca(OH)2 showed no catalytic activity for rapeseed oil methanolysis. However, the transesterification reaction rate could be enhanced by the use of ultrasound as well as by introduction of an appropriate co-solvent such as THF to increase methanol solubility in the phase containing the rapeseed oil. 

Methyl />-acetylbenzoate has been prepared by the esterification of -acetylbenzoic acid with methanol in the presence of hydrogen chloride,6 by the hydrogenation of methyl -trichloro-acetylbenzoate in the presence of a palladium on calcium carbonate catalyst,6 and by the air oxidation of methyl / -ethyl-benzoate.4... 

Mannich and Davidsen [31] also reported that most of the aldehydes were first converted to a diamino intermediate which on distillation afforded the enamine. Less successful was the attempt to extend the reaction to ketones. Only with the use of calcium oxide at elevated temperatures were the enamines directly obtained, but in poor yields. Herr and Heyl [32, 33] found that better yields of enamines from ketones can be obtained by the azeotropic removal of water in the presence or absence [32, 33] of acid catalysts [12a, b, 34, 35]... 

Dienes react quite readily with alkylbenzenes to form monoalkenylbenzenes under controlled experimental conditions. Sodium and potassium deposited on calcium oxide were found to be very suitable catalysts for these alkenylation reactions.240 Naphthalene-sodium in tetrahydrofuran is a very effective catalyst... 

Cadmium oxide, calcined dolomite, calcium chloride, calcium oxide, carbomethylcellulose (CMC), carbonates, catalysts, cellulose acetate, ceramics, charcoal, clay, coal, cocoa powder, coffee powder, coke, copper, corn starch... 

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