Promoters copper oxide

Monochlorohenzene is also produced in a vapor-phase process at approximately 300°C. The hy-product HCl goes into a regenerative oxychlorination reactor. The catalyst is a promoted copper oxide on a silica carrier ... 

Park PW, Ledford JS (1998) The influence of surface structure on the catalytic activity of cerium promoted copper oxide catalysts on alumina oxidation of carbon monoxide and methane. Catal Lett 50(1—2) 41 48... 

Shore, L., Ruettinger, W.F., and Farrauto, R.J. Platinum group metal promoted copper oxidation catalysts and methods for carbon monoxide remediation. United States Patent Application... 

Feedstocks which can be completely vaporized, can be treated in gas phase processes. At the conditions prevailing in the reactor (250 0-300 bar), several hundreds mol of hydrogen must be fed per mol of ester and, sometimes, methanol is needed to dilute the gas stream and to decrease the ester partial pressure. The energy necessary to drive the recycle compressor is therefore very important. The liquid space velocity is c. 0.35 hr . The absence of liquid in the reactor enables to use an unsupported catalyst of high activity. This catalyst is a promoted copper oxide which is very resistant to poisoning. The consumption of catalyst is less than 0.3. This catalyst is very pyrophoric it must be reduced inside the reactor. As the amount of catalyst per unit volume of reactor is higher than in slurries, the selectivity is also higher it can reach 9 Plants of 12000 t/a capacity have been built. 

When the operating temperature exceeds ca 93°C, the catalytic effects of metals become an important factor in promoting oil oxidation. Inhibitors that reduce this catalytic effect usually react with the surfaces of the metals to form protective coatings (see Metal surface treatments). Typical metal deactivators are the zinc dithiophosphates which also decompose hydroperoxides at temperatures above 93°C. Other metal deactivators include triazole and thiodiazole derivatives. Some copper salts intentionally put into lubricants counteract or reduce the catalytic effect of metals. 

This reaction is first conducted on a chromium-promoted iron oxide catalyst in the high temperature shift (HTS) reactor at about 370°C at the inlet. This catalyst is usually in the form of 6 x 6-mm or 9.5 x 9.5-mm tablets, SV about 4000 h . Converted gases are cooled outside of the HTS by producing steam or heating boiler feed water and are sent to the low temperature shift (LTS) converter at about 200—215°C to complete the water gas shift reaction. The LTS catalyst is a copper—zinc oxide catalyst supported on alumina. CO content of the effluent gas is usually 0.1—0.25% on a dry gas basis and has a 14°C approach to equihbrium, ie, an equihbrium temperature 14°C higher than actual, and SV about 4000 h . Operating at as low a temperature as possible is advantageous because of the more favorable equihbrium constants. The product gas from this section contains about 77% H2, 18% CO2, 0.30% CO, and 4.7% CH. ... 

Tertiary bismuthines appear to have a number of uses in synthetic organic chemistry (32), eg, they promote the formation of 1,1,2-trisubstituted cyclopropanes by the iateraction of electron-deficient olefins and dialkyl dibromomalonates (100). They have also been employed for the preparation of thin films (qv) of superconducting bismuth strontium calcium copper oxide (101), as cocatalysts for the polymerization of alkynes (102), as inhibitors of the flammabihty of epoxy resins (103), and for a number of other industrial purposes. 

GP 6] [R 5] With a stabilized CU2O catalyst layer, by addition of bromomethane (ppm level), 20% selectivity at 5% conversion was found (0.5 vol.-% propene 0.1 vol.-% oxygen 2.25 ppm promoter 350 °C) [37]. This is far better than with non-conditioned copper oxide catalysts which contain CuO besides CU2O. It is expected that the first species promotes more total oxidation, whereas the latter steers partial oxidation. In the above experiment, selectivity rises from 7 to 30% at slightly reduced conversion after 3 h of promoter conditioning. 

An example of an experiment in which LDL has been treated with 15-lipoxygenase and the oxidation monitored by the formation of conjugated diene is shown in Fig. 2.2. In the absence of transition metal, a rapid increase in absorbance occurs, with no lag phase, which ceases after a period of about 90 min under these conditions. If copper is added to promote LDL oxidation at this point, LDL treated with lipoxygenase oxidizes at a faster rate with a short lag phase when compared to the control. During this procedure there is only a minimal loss of a-tocopherol and so we may ascribe the shortened lag phase to the increase in lipid peroxides brought about by lipoxygenase treatment. A similar result was found when LDL was supplemented with preformed fatty acid hydroperoxides (O Leary eta/., 1992). 

This equilibrium has a buffer-like effect stabilizing the presence of cationic copper species in the structure even in a highly reductive atmosphere. The above scheme of copper oxide-ceria interactions indicates clearly that the catalyst is mutually promoted, i.e., both copper and ceria cooperate in the redox mechanism. 

Figure 1. First order plots based on hydrogen evolution for the oxidative dehydrogenation of ethanolamine (EA), 2-(2-aminoethylamino)ethanol (AEAE), 3-amino-1-propanol (AP), 2-(methylamino)ethanol (MAE) and benzyl alcohol (BA) over chromia-promoted copper.

Mechanical components used in fuel systems such as pumps, valves, and bearings may contain copper or copper-containing alloys. As a fuel system component, copper is especially undesirable because it acts as a catalyst in promoting the oxidation of fuel paraffins to oxygen-rich, gumlike deposits. The following reaction sequence represents how copper ions can catalyze the oxidation and degradation of hydrocarbons. 

Vaccinium myrtillus, commonly known as bilberry fruit, originates mainly from northern and central Europe (Bisset, 1994). This well known plant is rich in flavonoids, the polyphenolic compounds that promote anti-oxidant activity (Bisset, 1994). A study conducted on the antioxidative potential of V. myrtillus showed potent protective action on LDL particles during in vitro copper-mediated oxidation. The study concluded that this extract may be more potent than either ascorbic acid or butylated hydroxy-toluene in the protection of LDL particles from oxidative stress (Mitcheva, 1993 Bisset, 1994). 

Research on the important, and difficult, problem of removing small quantities of carbon monoxide from the air has shown that this can be best effected, by catalytic oxidation at room temperature, by mixtures of oxides, which are far more effective than any of the oxides singly.2 While neither manganese dioxide, silver oxide, nor copper oxide will oxidize carbon monoxide rapidly at room temperature, mixtures of manganese dioxide and copper oxide (60/40) will do so silver oxide also much accelerates the oxidation by manganese dioxide. It is stated that 1 per cent, of potash is beneficial, but larger amounts retard the oxidation. Not all oxides accelerate thus cobalt oxide retards oxidation. Various mixtures of manganese dioxide and other oxides as promoters are sold as Hopcalite. ... 

The noble metals and their oxides, especially palladium, are used chiefly as promoters of other catalysts. Small amounts of palladium, less than 1%, greatly increase the catalytic action of copper oxide for the combustion of CO near room temperature (58). Hurst and Rideal (59) found that a copper catalyst activated by Pd showed increased adsorption of CO and also increased the ratio of oxidized CO to oxidized H2 when the combustion was carried out in a mixture of these gases containing 02. 

With adjustment of the steam/methane ratio, the reactor can produce a synthesis gas with CO/H2 = 1/2, the stoichiometric proportions needed for methanol production. This mixture at approximately 200 atm pressure is fed to the methanol unit where the reaction then proceeds at 350°C. Per pass conversions range from 30 to 50 over the catalyst— typically a supported copper oxide with a zinc, chromium, or manganese oxide promoter 3... 

Chlorides and bromides of both oxidation states of copper, as well as cuprous cyanide, are active in promoting the oxidative cleavage of the enamine double bond (Scheme 21). 

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