Copper mixed catalysts

When catalysts are used in a highly exothermic reaction, an active phase may be diluted with an inert material to help dissipate heat and moderate the reaction. This technique is practiced in the commercial oxychlorination of ethylene to dichloroethane, where an alumina-supported copper haUde catalyst is mixed with a low surface area inert diluent. 

Ruthenium dioxide or ruthenium-on-carbon are effective catalysts for hydrogenation of mono- and dicarboxylic acids to the alcohol or glycol. High pressures (5,000-10,000 psig) and elevated temperatures (130-225 C) have been used in these hydrogenations 8,12,24). Yields of alcohol tend to be less than perfect because of esterification of the alcohol. Near quantitative yields of alcohol can be obtained by mixing ruthenium and copper chromite catalysts so as to reduce the ester as formed. 

Several other important commercial processes need to be mentioned. They are (not necessarily in the order of importance) the low pressure methanol process, using a copper-containing catalyst which was introduced in 1972 the production of acetic add from methanol over RhI catalysts, which has cornered the market the methanol-to-gasoline processes (MTG) over ZSM-5 zeolite, which opened a new route to gasoline from syngas and ammoxidation of propene over mixed-oxide catalysts. In 1962, catalytic steam reforming for the production of synthesis gas and/or hydrogen over nickel potassium alumina catalysts was commercialized. 

Oxyhydrochlorination A two-stage process for making gasoline from lower paraffinic hydrocarbons, especially methane. The methane, mixed with oxygen and hydrogen chloride, is passed over a supported copper chloride catalyst, yielding a mixture of chloromethanes ... 

Copper-catalyzed Suzuki cross-coupling reactions using mixed nanocluster catalysts have been studied recently. Copper-based catalysts were shown to be effective as reagents that can present an inexpensive and environmentally friendly alternative to noble metal catalysts. In the hydrogenation of cinnamic acid to corresponding alcohol, the selectivity can be varied by doping Sn with Rh colloid catalysts. A selectivity of 86% was achieved using a colloidal Rh/Sn (Rh/Sn = 1.5 1) catalyst on... 

Mix 16.7 g potassium sulfate, 0.6 g titanium dioxide, 0.01 g anhydrous copper sulfate, and 0.3 g pumice and grind fine in a crucible. The mixed catalyst powder is stable under usual laboratory storage conditions at room temperature. Avoid moisture to prevent from caking. Commercially premixed tablets are also available. 

Esters may alternatively be reduced to primary alcohols either using hydrogen under pressure in the presence of a copper chromite catalyst,56 or with lithium aluminium hydride (Expt 5.38), but not with sodium borohydride which is insufficiently reactive. However it has been found recently that sodium borohydride in mixed solvents (methanol/tetrahydrofuran) reduces /1-ketoesters to 1,3-diols, and this method offers a convenient route to this type of compound.57... 

The catalysts were evaluated by exposure to a simulated automobile exhaust gas stream composed of 0.2% isopentane, 2% carbon monoxide, 4% oxygen and a balance of nitrogen. The temperature required to oxidize the isopentane and carbon monoxide was used to compare catalyst performance. The chromium-promoted catalyst oxidized isopentane at the lowest temperature, and a mixed chromium/copper-promoted catalyst proved the most efficient for oxidizing carbon monoxide and isopentane. It is interesting to note that the test rig used a stationary engine with 21 pounds of catalyst. Although the catalyst was very effective it is difficult to envisage uranium oxide catalysts employed for emission control of mobile sources. 

The reaction of hydrogen with CO forms the basis of an industrial process for making methanol carried out at high pressure over a mixed copper-zinc catalyst. Though CO is insoluble in, and unrcactive with, water at ordinary pressures, formic acid is produced at very high pressures. Under similar conditions CO and aqueous NaOH combine to give sodium formate. 

If 2-methylfuran is to be made intentionally, it was found that the reaction temperature should be 250 °C (instead of 135 °C for furfuryl alcohol), and that the copper chromite catalyst should be mixed with activated charcoal [110]. As the reaction is highly exothermic, good care must be exercised to prevent an inactivation of the catalyst by overheating. 

The preparation technique of the methanol catalysts plays an important role on their catalytic behavior. For each catalytic composition a specific preparation technique is able to optimize the catalytic properties. The precipitation by Na2C03 seems to be the most suitable way for the preparation of copper zinc catalysts and also of promoted systems. But the use of precipitation of mixed oxalates allows the best methanol yield on copper-pyrochlore catalysts. 

Two kinds of catalyst precursors were mainly employed in this work. One was the mixed oxide of Cu60sLn(N03), prepared by pyrolysis of the mixture of corresponding nitrates under O2 flow at 673 K, referred to in previous reports [7,11,12], The other was the homogeneous mixture of the corresponding oxides, which was prepared by calcination of the hydroxide coprecipitate, obtained by the hydrolysis of the mixed nitrate solution added with NaaCOs solution (0.05 mol/1) and washing the obtained coprecipitates with distilled water several times until the pH of the supernatant solution was dropped to 7, at prescribed temperature. The copper-oxide catalyst systems were obtained by the reduction of the prepared precursors under H2 (300 Torr 1 Torr=l33.32 Pa) at prescribed temperatures before the reaction. 

It is concluded that copper-oxide catalyst system, particularly copper-lanthanide oxide catalyst system, show a high activity for CO hydrogenation. The effective condition of the catalyst is the homogeneous mixture of copper and oxide where a fine particle of the oxide dispersed homogeneously in the copper metal and the active eatalyst can be prepared from the mixed oxide of CueOgLnfNOj) and the homogeneous oxide mixture obtained from the calcination of the hydroxide coprecipitate. If the combined oxides were changed. 

Formation of the mixed cement-containing systems within the range of low copper concentrations with addition of alkali metal dopants as well as catalytical properties of these systems in the ethane oxidative chlorination process have been investigated. Based on the obtained data the efficient and stable copper-cement catalyst has been worked out. This catalyst will assist in the development of a new technology of the vinyl chloride production from ethane. The basic peirameters of the ethane oxychlorination process have been determined at 623-673K, time-on-stream 3-5s and reactant ratio of C2H6 HCI 02 = 1 2 1 the conversion of ethane is more than 90% and the total selectivity to ethylene and vinyl chloride is 85-90%. 

Di-n-propylamine can be produced in industrial scale by the alkylation of ammonia with n-propanol on Ba(OH)2 modified Ni/Al203 catalyst [2], by the reductive amination of propionaldehyde over a cobalt-containing catalyst [3] or by the hydrogenation acrylonitrile in n-exane on Ni/Al203 catalyst [4,5]. However, only scare data is available about the alkylation of ammonia or i-butylamine with i-butanol [6-10]. Di-i-butylamine was prepared from i-butanol over alumina at 370-380 C with 28 % yield [7]. 20 wt% Co - 5 wt% Ni catalyst supported on alumina was used to prepare di-i-butylamine fi"om i-butanol and i-butylamine at 200 °C with a yield of 60. 6 [10]. Aliphatic mixed secondary amines prepared from a pimary amine and an alcohol were usually obtained on copper-containing catalysts at 190-200 C with 30-50 % yields [11-13]. 

In the preparation of EtNHn-Bu from ethylamine and n-butanol over a commercial CuO-ZnO-AI2O3 catalyts the highest yield, about 76 % was obtained at 190 C and EtNH2/n-BuOH molar ratio 5 or above. Here we report the first time such a high yield in the preparation of a mixed aliphatic secondary amine over a copper-containing catalyst. 

A slurry phase concurrent synthesis of methanol using a potassium meth-oxide/copper chromite mixed catalyst has been developed. This process operates under relatively mild conditions such as temperatures of 100-180°C and pressures of 30-65 atm. The reaction pathway involves a homogeneous carbonylation of methanol to methyl formate followed by the heterogeneous hydrogenolysis of methyl formate to two molecules of methanol, the net result being the reaction of hydrogen with carbon monoxide to give methanol via methyl formate ... 

The nickel content of carrier catalysts is usually 10-40%. Nickel catalysts are generally reduced at 300-500° but nickel mixed catalysts, containing metals nobler than nickel, can be reduced at lower temperatures, e.g., copper-nickel mixed catalysts168 as low as 200-300°. 

Copper can also be used as a catalyst, like nickel, alone, on carriers, or as a mixed catalyst with metals of the first to the eighth Group of the Periodic Table. The temperature needed for reduction of the catalyst, usually containing the copper as oxide, hydroxide, or basic carbonate, is 150-300°. Preparation of a copper-kieselguhr catalyst is similar to that of a nickel-kieselguhr catalyst.175... 

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