Methanol catalytic chemical conversion

Several different processes have been proposed for the conversion of solid organic wastes to a more usable liquid or gaseous form to be utilized as fuel or petrochemical feedstocks. Principally the commonly discussed processes involve the biological conversion to alcohols, the catalytic chemical conversion to methanol or Fischer-Tropsch liquids via a carbon monoxide and hydrogen synthesis gas, or the thermochemical formation of gases or oxygenated liquids by pyrolysis. Pyrolysis is defined as the decomposition of organic material at elevated temperatures. The process to be described uses a very special case of pyrolysis. 

In 1992, Tomoda and Iwaoka reported the first catalytic chemical conversion of alkenes into allylic ethers and esters [310]. The reactions were performed anploy-ing 10 mol% of diselenides 455 or 456 (Fig. 7.27) and copper (11) nitrate trihydrate in methanol or acetic acid in the presence of excess of sodium persulfate as an oxidizing agent. The best results were achieved when using the diselenide 456 in the presence of molecular sieves 3 A in acetic acid (Scheme 7.69). This suggests that... 

The accepted papers cover every aspect of catalysis on microporous materials. A significant number of contributions describe the synthesis, modification, instrumental and chemical characterisation of zeolites and other micro- and mesoporous materials. Catalytic reactions involve hydrocarbon cracking, nucleophilic aromatic substitution, methanol to hydrocarbon conversion, hydration of acetylene, various alkylation reactions, redox transformations, Claisen rearrangement, etc. A whole range of appealing chemistry can be enjoyed by reading the contributions. 

Synthesis Gas Chemicals. Hydrocarbons are used to generate synthesis gas, a mixture of carbon monoxide and hydrogen, for conversion to other chemicals. The primary chemical made from synthesis gas is methanol, though acetic acid and acetic anhydride are also made by this route. Carbon monoxide (qv) is produced by partial oxidation of hydrocarbons or by the catalytic steam reforming of natural gas. About 96% of synthesis gas is made by steam reforming, followed by the water gas shift reaction to give the desired H2 /CO ratio. 

The electrolysis in aqueous sulfuric acid with methanol as a cosolvent was perfomed in a filterpress membrane cell stack developed at Reilly and Tar Chemicals. Because of the low current density of the process, a cathode based on a bed of lead shot was used. A planar PbOa anode was used. The organic yield was 93% with approximately 1% of a dimer. The costs of the electrochemical conversion were estimated as one-half of the catalytic hydrogenation on a similar scale. 

The CH-activation of alkanes and especially of methane and their catalytic conversion to alcohols is one of the major challenges for chemists. Methane as the major part of natural gas is currently the cheapest source of hydrocarbons and the need for methanol will increase in the near future. Methane conversion to methanol would make a conveniently transportable fuel and also a new carbon source for the chemical industry. 

In toluene with 4 equiv methanol and a catalytic amount of the alkaloid. b ee values are determined by conversion of the monoesters to the (R)-l-(l-naphthalenyl)ethylamides (entries 1-14) and analysis by HPLC, by salt formation with (R)-l-phenylethylamine (entries 15-20) or by H-NMR spectroscopy in the presence of Eu(hfc)3. Absolute configurations are determined by chemical correlation or by X-ray analysis of the Mosher ester of the lactone alcohol (entry 21). With 20 equiv of methanol. d With 4 equiv of methanol. With 10 equiv of methanol. f With 3 equiv of methanol. 

Research on the direct conversion of chemical energy to electricity via fuel cells has received considerable attention in the past decades. Fuel cells are indeed attractive alternatives to combustion engines for electrical power generation in transportation applications and also as promising future power sources, especially for mobile and portable applications. Thus, the search for excellent electrocatalysts for the electro-catalytic oxygen reduction and methanol oxidation reactions, which are the two important cathodic and anodic reactions in fuel cells, is intensively pursued by scientists... 

It is well-known that catalytic amounts of aldehyde can induce racemization of a-amino acids through the reversible formation of Schiff bases.61 Combination of this technology with a classic resolution leads to an elegant asymmetric transformation of L-proline to D-proline (Scheme 6.8).62 63 When L-proline is heated with one equivalent of D-tartaric acid and a catalytic amount of n-butyraldehyde in butyric acid, it first racemizes as a result of the reversible formation of the proline-butyraldehyde Schiff base. The newly generated D-proline forms an insoluble salt with D-tartaric acid and precipitates out of the solution, whereas the soluble L-proline is continuously being racemized. The net effect is the continuous transformation of the soluble L-proline to the insoluble D-proline-D-tartaric acid complex, resulting in near-complete conversion. Treatment of the D-proline-D-tartaric acid complex with concentrated ammonia in methanol liberates the D-proline (16) (99% ee, with 80-90% overall yield from L-proline). This is a typical example of a dynamic resolution where L-proline is completely converted to D-proline with simultaneous in situ racemization. As far as the process is concerned, this is an ideal case because no extra step is required for recycle and racemization of the undesired enantiomer and a 100% chemical yield is achievable. The only drawback of this process is the use of stoichiometric amount of D-tartaric acid, which is the unnatural form of tartaric acid and is relatively expensive. Fortunately, more than 90% of the D-tartaric acid is recovered at the end of the process as the diammonium salt that can be recycled after conversion to the free acid.64... 

The deactivation of catalysts, especially zeolites, during cracking, hydrocracking, methanol conversion, etc, is one of the major technological and economic problems of the chemical industry (1). The interest of these materials lies not only in their high catalytic activity and selectivity but also in the possibility of regenerating them several times so that their Lifetime" is compatible with the cost of their production. Consequently, it is necessary to understand the manner and the rate of catalyst deactivation as well as the nature of the carbonaceous residues formed, commonly called coke". 

Methanol. Methanol is a water-soluble, low molecular weight alcohol that may be of increasing importance as a low-sulfur fuel, a chemical feedstock, and perhaps as a gasoline additive or an intermediate in gasoline production. The synthesis of methanol is accomplished by the catalytic conversion of synthesis gas containing two moles of hydrogen for each mole of carbon monoxide. Methanol synthesis is widely practiced in industry on a commercial scale. See Chapter 10 for a discussion of methanol manufacture. 

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