Copper-based catalyst

Manufacture. Furfuryl alcohol has been manufactured on an industrial scale by employing both Hquid-phase and vapor-phase hydrogenation of furfural (56,57). Copper-based catalysts are preferred because they are selective and do not promote hydrogenation of the ring. 

The chemical complex includes the methanol plant, methyl acetate plant, and acetic anhydride plant. The methanol plant uses the Lurgi process for hydrogenation of CO over a copper-based catalyst. The plant is capable of producing 165,000 t/yr of methanol. The methyl acetate plant converts this methanol, purchased methanol, and recovered acetic acid from other Eastman processes into approximately 440,000 t/yr of methyl acetate. 

The one-step route from 2-propanol coproduces diisobutyl ketone and acetone, and is practiced in the United States by Union Carbide (61). The details of a vapor-phase 2-propanol dehydrogenation and condensation process for the production of acetone, MIBK, and higher ketones have been described in recent patents (62,63). The process converts an a2eotropic 2-propanol—water feed over a copper-based catalyst at 220°C and produces a product mixture containing 2-propanol (11.4%), acetone (52.4%), MIBK (21.6%), diisobutyl ketone (6.5%), and 4-methyl-2-pentanol (2.2%). 

Dehydrogenation processes for acetone, methyl isobutyl ketone [108-10-1], and higher ketones (qv) utilizing, in one process, a copper-based catalyst have been disclosed (18,19). Dehydrogenation reaction is used to study the acid—base character of catalytic sites on a series of oxides (20,21). 

Currently, acrylamide is produced by the hydration of acrylonitrile in the presence of copper-based catalysts. 

A low-pressure process has been developed by ICl operating at about 50 atm (700 psi) using a new active copper-based catalyst at 240°C. The synthesis reaction occurs over a bed of heterogeneous catalyst arranged in either sequential adiabatic beds or placed within heat transfer tubes. The reaction is limited by equilibrium, and methanol concentration at the converter s exit rarely exceeds 7%. The converter effluent is cooled to 40°C to condense product methanol, and the unreacted gases are recycled. Crude methanol from the separator contains water and low levels of by-products, which are removed using a two-column distillation system. Figure 5-5 shows the ICl methanol synthesis process. 

For recent reviews of cross-coupUng reactions with copper-based catalyst, see (a) Lindley J (1984) Tetrahedron 40 1433-1456 (b) Ley SV, Thomas AW (2003) Angew Chem Int Ed 42 5400-5449 (c) Kunz K, Scholz U, Ganzer D (2003) Synlett 2428-2439 (d) Beletskaya IP, Cheprakov AV (2004) Coord Chem Rev 248 2337-2364... 

The replacement of vanadia-based catalysts in the reduction of NOx with ammonia is of interest due to the toxicity of vanadium. Tentative investigations on the use of noble metals in the NO + NH3 reaction have been nicely reviewed by Bosch and Janssen [85], More recently, Seker et al. [86] did not completely succeed on Pt/Al203 with a significant formation of N20 according to the temperature and the water composition. Moreover, 25 ppm S02 has a detrimental effect on the selectivity with selectivity towards the oxidation of NH3 into NO enhanced above 300°C. Supported copper-based catalysts have shown to exhibit excellent activity for NOx abatement. Recently Suarez et al and Blanco et al. [87,88] reported high performances of Cu0/Ni0-Al203 monolithic catalysts with NO/NOz = 1 at low temperature. Different oxidic copper species have been previously identified in those catalytic systems with Cu2+, copper aluminate and CuO species [89], Subsequent additions of Ni2+ in octahedral sites of subsurface layers induce a redistribution of Cu2+ with a surface copper enrichment. Such redistribution... 

ICI Low Pressure Methanol A process for making methanol from methane and steam. The methanol is first converted to syngas by steam reforming at a relatively low pressure. The syngas is then converted to methanol over a copper-based catalyst ... 

Our new approach has proven its initial value in both palladium-(Schareina et al. 2004) and copper-catalyzed cyanations (Schareina et al. 2005) and has been adopted by other groups. Very recently, in a joint collaboration with Saltigo GmbH we developed a new and improved copper-based catalyst system, which allows for efficient cyanations of a variety of aromatic and heteroaromatic halides. Importantly, notoriously difficult substrates react in excellent yield and selectivity, making the method applicable on an industrial scale. 

Inspection of Table 2 shows that there is a wide range of activities exhibited by copper based catalysts. It is often considered that, on the basis of the principle of... 

For the low-temperature case, copper based catalysts were utilized, and they continue to be the catalyst of choice. 

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... 

Centi, G. and Perathoner, S. Nature of active species in copper-based catalysts and their chemistry of transformation of nitrogen oxides. Appl Catal, A General, 1995, Volume 132, Issue 2, 179-259. 

This methodology was applied to a concise synthesis of the alkaloid epilupinine (Scheme 18.10) [27]. N-alkylation of proline benzyl ester with bromo diazoketone 25 gave substrate 26. Treatment with either Rh2(OAc)4 or various copper-based catalysts... 

After the optimization of these conditions, by adding an azide to the input stream it was possible to synthesize a range of substituted triazoles in a heterogeneously catalysed three-component reaction (Scheme 18). After the CFC, the stream was passed through a column containing a resin-immobilized copper-based catalyst, which was used in a previous work by the same authors to successfully catalyze the formation of triazoles from alkynes and azides [44]. An immobilized thiourea-containing cartridge was subsequently used to remove any leached Cu catalyst. In a similar way as for the alkynes production, the series of resins was used to purify the product. 

Two major pathways for CSRM have been suggested using copper-based catalysts (i) a decomposition-WGSR sequence and (ii) dehydrogenation of methanol to methyl formate (Equation 6.7). 

The formation of by-products in the steam reforming reaction over copper-based catalysts is generally lo v. The formation of products such as CO, formic acid and methyl formate, which was reported by some researchers [103, 105-107], is significant as it poses a threat to the performance of the fuel cells. It is possible to minimize the formation of CO by operating the CSRM in an excess of steam, thereby integrating the WGSR into the reformer. 

The group 10 metals, such as palladium and platinum, are active for the conversion of methanol. However, they are much less selective than the copper-based catalysts, yielding primarily the decomposition products [123,124,133]. This catalytic property makes them less feasible for fuel cell applications. The only exception found is for Pd/ZnO, which showed selectivity close to that of a copper catalyst [105, 121]. 

Copper based catalysts have long been considered as the only effective methanol synthesis catalysts. However, Poutsma et al. (7) showed that palladium catalysts were active in methanol synthesis from CO-H. This latter metal had been previously considered as either almost inactive or active only for methane formation (8). Furthermore it is now known that both activity and selectivity can change drastically with the support. Vannice (9) observed that the methanation activity of a Pd/Al O was enhanced eighty and forty times compared to palladium black or Pd/SiO (or Pd/TiO ) respectively. The support effect on the selectivity was pointed out by many authors even at atmospheric pressure when the reaction temperature... 

A high temperature water-gas shift reactor 400°C) typically uses an iron oxide/chromia catalyst, while a low temperature shift reactor ( 200°C) uses a copper-based catalyst. Both low and high temperature shift reactors have superficial contact times (bas on the feed gases at STP) greater than 1 second (72). 

Methanol was first produced commercially in 1830 by the pyrolysis of wood to produce wood alcohol. Almost a century later, a process was developed in Germany by BASF to produce synthetic methanol from coal synthesis gas. The first synthetic methanol plant was introduced by BASF in 1923 and in the United States by DuPont in 1927. In the late 1940s, natural gas replaced coal synthesis gas as the primary feedstock for methanol production. In 1966, ICI announced the development of a copper-based catalyst for use in the low-pressure synthesis of methanol. 

In certain cases, when the palladium or nickel catalyzed coupling is not efficient or fails completely, an alternate solution is provided by the use of copper based catalyst systems. The 5-iodouracil derivative shown in 7.77. was unreactive towards imidazole using either the Buchwald-Hartwig conditions or the copper(I) triflate promoted the carbon-nitrogen bond formation reported by Buchwald98 These latter conditions, however, were effective in coupling the iodouracil with a series of other amines (7.77.), The optimal catalyst system consisted of copper(I) triflate, phenantroline and dibenzylideneacetone (dba).99... 

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