Copper catalysis methanol

Oxidation catalysts are either metals that chemisorb oxygen readily, such as platinum or silver, or transition metal oxides that are able to give and take oxygen by reason of their having several possible oxidation states. Ethylene oxide is formed with silver, ammonia is oxidized with platinum, and silver or copper in the form of metal screens catalyze the oxidation of methanol to formaldehyde. Cobalt catalysis is used in the following oxidations butane to acetic acid and to butyl-hydroperoxide, cyclohexane to cyclohexylperoxide, acetaldehyde to acetic acid and toluene to benzoic acid. PdCh-CuCb is used for many liquid-phase oxidations and V9O5 combinations for many vapor-phase oxidations. 

Gadhe, J.B., Gupta, R.B. 2007. Hydrogen production by methanol reforming in supercritical water catalysis by in situ-generated copper nanoparticles. Int J Hydrogen Energy 32 2374-2381. 

DMT can be made from crude TA or from />-xylene directly. Esterification of TA with methanol occurs under sulfiiric acid catalysis. Direct oxidation of /7-xylene with methanol present utilizes copper and manganese salt catalysis. 

Hydrolysis of Ar-salicylidene-2-aminopyridine (120 = HL) in aqueous 5% methanol, in the presence and absence of copper(II), has been the subject of a detailed kinetic study.409 The imine anion (L-) is found to undergo hydroxide-independent hydrolysis with k = 3.5 x 10-2 s 1 at 35 °C. The observed solvent deuterium isotope effect (kn /k o = 1-6) for this pathway is consistent with intramolecular catalysis by the phenoxide ion. The copper(II) complex undergoes acid-catalysed hydrolysis of the imine linkage with it = 4.4 x 102 M I s 1 at 35 °C. 

This section reports a series of examples of application of the cluster model approach to problems in chemisorption and catalysis. The first examples concern rather simple surface science systems such as the interaction of CO on metallic and bimetallic surfaces. The mechanism of H2 dissociation on bimetallic PdCu catalysts is discussed to illustrate the cluster model approach to a simple catalytic system. Next, we show how the cluster model can be used to gain insight into the understanding of promotion in catalysis using the activation of CO2 promoted by alkali metals as a key example. The oxidation of methanol to formaldehyde and the catalytic coupling of prop)me to benzene on copper surfaces constitute examples of more complex catalytic reactions. 

Frank, B., Jentoft, F.C., Soerijanto, H., Krohnert, J., Schlogl, R., and Schomacker, R. Steam reforming of methanol over copper-containing catalysts Influence of support material on microkinetics. Journal of Catalysis, 2007, 246 (1), 177. 

Takezawa, N. and Iwasa, N. Steam reforming and dehydrogenation of methanol Difference in the catalytic functions of copper and group VIII metals. Catalysis Today, 1997, 36 (1), 45. 

In the following we will investigate the methanol oxidation process over silver, copper and heteropoly molybdates in order to identify the occurrence of the possible reaction pathways from Schemes 2 and 3 on polycrystalline surfaces and at atmospheric pressure. The main emphasis in these experiments will be on the source of active oxygen. This focus was chosen to better understand the involvement of bulk and sub-surface [10,48] chemistry in selective oxidation catalysis. Such an understanding is required when the catalytic performance is compared between series of chemically different systems which are chosen to investigate only one surface property such as acidity. These experiments will naturally only cover a small selection of the problems discussed with the reaction Schemes. 

The nature of the outer-layer of the Cu-Zn based catalysts and the role of the different active sites are still a topic of investigation. Metallic copper is implicated as being the dominant oxidation state of the metal during the reaction. However, the presence of Cu+ is also important as a small amount of oxygen increases the reaction rate.51,66 Shen et al.67 found on ceria supported copper catalyst that in spite of the reductive reaction atmosphere, metallic copper particles on cerium oxide were oxidised during reaction and the catalyst was activated. The formation of the copper oxide species was considered indispensable for the onset of high catalytic activity. Synergy between Cu and ZnO in the catalysis of methanol synthesis... 

Methanol catalysts composed of zinc and copper oxides arc decidedly crystalline in structure as evidenced by an X-ray examination. Although catalysis is ordinarily thought to be a surface effect, it seems to be closely... 

Several new methods for the preparation of 1-haloalkynes have been described. High yields of bromo compounds, e.g. 28, are obtained by treatment of alkynes with triphenylphosphine/carbon tetrabromide, or with a concentrated aqueous solution of potassium hypobromite and potassium hydroxide (equation 1). 1-Iodoalkynes are produced from terminal alkynes and bis(pyridine)iodine(I) tetrafluoroborate in methanol in the presence of sodium methoxide (equation 2) or from alkynes with a mixture of iodine, potassium carbonate, copper(I) iodide and tetrabutylammonium chloride under phase-transfer catalysis. Lithium acetylides 29 (R = Ph, t-Bu, HOCH2 etc.) react with zinc iodide and bis(trimethylsilyl) peroxide to yield 1-iodoalkynes. The method has been... 

T. Matsuda, K. Yogo, C. Pantawong, and E. Kikuchi, Catalytic properties of copper-exchanged clays for the dehydrogenation of methanol to methyl formate. Applied Catalysis A General, 126 (1995), 177-86. 

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