Methanol, production sulfur

Catalytic gas-phase reactions play an important role in many bulk chemical processes, such as in the production of methanol, ammonia, sulfuric acid, and nitric acid. In most processes, the effective area of the catalyst is critically important. Since these reactions take place at surfaces through processes of adsorption and desorption, any alteration of surface area naturally causes a change in the rate of reaction. Industrial catalysts are usually supported on porous materials, since this results in a much larger active area per unit of reactor volume. 

The production of synthesis gas from natural gas and coal is the basis of the 33 000000 tpa methanol production and is also used in the production of ammonia. After removal of sulfur impurities, methane and water are reacted over a nickel oxide on calcium aluminate catalyst at 730 °C and 30 bar pressure. The reaction is highly endothermic (210 kJmol ) (Equation 6.6). 

Methyl 2-furoate was dimethoxylated using methanol in sulfuric acid to give methyl-2,5-dihydro-2,5dimethoxy-2-furan carboxylate [70]. The reaction mechanism at the electrodes is not completely known. However, the anodic reaction is said to be the oxidation of methanol. A two-electron process is assumed and hydrogen production is observed at the cathode. 

Ota K-I, Nakagawa Y, Takahashi M. 1984. Reaction products of anodic oxidation of methanol in sulfuric acid solution. J Electroanal Chem 179 179-186. 

Unsymmetrical ethers may be produced from the acid-promoted reactions of aldehydes and organosilicon hydrides when alcohols are introduced into the reaction medium (Eq. 173).327,328 An orthoester can be used in place of the alcohol in this transformation.327 335 A cyclic version of this conversion is reported.336 Treatment of a mixture of benzaldehyde and a 10 mol% excess of triethylsilane with methanol and sulfuric, trifluoroacetic, or trichloroacetic acid produces benzyl methyl ether in 85-87% yields.328 Changing the alcohol to ethanol, 1-propanol, 2-propanol, or 1-heptanol gives the corresponding unsymmetrical benzyl alkyl ethers in 45-87% yield with little or no side products.328 A notable exception is the tertiary alcohol 2-methyl-2-propanol, which requires 24 hours.328 1-Heptanal gives an 87% yield of //-lie ply I methyl ether with added methanol and a 49% yield of benzyl n-heptyl ether with added benzyl alcohol under similar conditions.328... 

PHA content and composition in the lyophilized cell material were determined using gas chromatography (GC) and nuclear magnetic resonance (NMR) analyses. For GC analysis [17], approximately 15 mg of lyophihzed cell was subjected to methanolysis in the presence of methanol and sulfuric acid [85% 15% (v/v)]. The reaction mixture was incubated at 100°C for 3 hours. The organic layer containing the reaction products was separated, dried over Na SO, and analyzed by GC. For... 

The impressive activity achieved by Teles catalyst was improved some years later by the use of CO as an additive [92]. In this study, Hayashi and Tanaka reported a TOF of 15600h 1, at least two orders of magnitude higher than [as-PtCl2(tppts)2], for the hydration of alkynes, providing an alternative synthetic route to the Wacker oxidation. Although several solvents were tested, the best results were obtained with aqueous methanol, and sulfuric acid or HTfO as acidic promoters. Unlike Utimoto s observation, in this case terminal propargylic alcohols partially (17-20%) delivered anti-Markovnikov product, in addition to the Markovnikov species. Some years before, Wakatsuki et al. had already reported the anti-Markovnikov hydration of terminal alkynes catalyzed by ruthenium(II) [93]. 

We will consider three processes in more detail to show how the sulfur in the original feedstock material (coal or oil shale) is recovered as elemental by-product sulfur. In this way yields of sulfur per barrel of product can be computed. The three processes will illustrate examples of coal gasification for production of SNG, methanol or indirect liquids, direct liquefaction for production of naphtha and synthetic crude oil and finally, oil shale retorting for production of hydrotreated shale oil. 

Thus a variety of hydrocarbons, ranging from natural gas to coal, are used in methanol production. Regardless of the feedstock used to prepare the synthesis gas, it is necessary to remove sulfur so that the converter catalyst is not poisoned. Before natural gas or naphtha is reformed, the feedstock is desulfurized. In the partial oxidation and coal gasification processes, the feedstock is first oxidized and the resulting synthesis gas is desulfurized before entering the converter. 

To achieve this, soapstock was reacted under pressure with methanol and sulfuric acid as the catalyst at 130°C-180°C and up to 500psi. Without the intermittent removal of the by-products water and glycerol, the reaction equilibrated at about 10 AN (acid number), or approximately an 82% conversion... 

Many of the metal oxide materials used for making ceramic membranes, particularly the porous type, have also been used or studied as catalysts or catalyst supports. Thus, they are naturally suitable to be the membrane as well as the catalyst. For example, alumina surface is known to contain acidic sites which can catalyze some reactions. Alumina is inherently catalytic to the Claus reaction and the dehydration reaction for amine production. Silica is used for nitration of benzene and production of carbon bisulfide from methanol and sulfur. These and other examples are highlighted in Table 9.6. 

Compare the growth rate of methanol production between 1955 and 1970 with the growth rate of (a) sulfuric acid, (b) benzene and (c) ethylene. 

GLC with an FID detector, it was confirmed by isotacophoresis analysis and by the formation of methyl formate when the product solution was treated with methanol containing sulfuric acid. No other low boiling carboxylic acid was observed by GLC except a trace amount of acetic acid. Therefore, the formation of formic acid was estimated as indicated in Table I. This estimate agreed fairly well with that determined by isotacophoresis analysis. Little formation of other low boiling products was observed. 

The catalytic reactions were carried out in a catalytic flow microreactor at atmosheric pressure and various temperatures. The catal ic bed (Ig) was covered by silica. TTie reaction conditions were the following the oil (40(wt%) in cyclohexane) was introduced with a flow of 0.12 mkmin l simultaneoulsy with hydrogen (flow = 20 mIxmin H. After evaporation of the solvant, the products were successively treated by sodium methoxide, methanol and sulfuric acid to obtain the free-esters before analysis. The final products were analysed by gas chromatography with a flame ionization detector and AT-FILAR (Altech) capillary column (30m, I.d = 0.32 pm, film thickness = 0.25 pm) at 140 C. 

Vinyl compounds are widely used in the industry in manufacture of various resins and polymers and the like. Methacrylic acid and methyl methacrylate are especially attractive as row materials of polymethyl methacrylate that is an important polymer so-called "organic glass." Until a new process consisting of two-step oxidation of isobutylene was commercially practiced in 1982, methyl methacrylate had been produced by the "Acetone Cyanohydrine Process," which uses acetone, hydrogen cyanide, methanol, and sulfuric acid as raw materials. Technical and economical drawbacks of this process have spurred a considerable industrial research effort to develop an alternate route to methacrylic acid and methyl methacrylate. Therefore, many attempts have been focused on the production of these compounds by aldol-type condensation using HCHO. 

A Striking use of a solvent or additive is in the manufacture of dimethylaniline (DMA) (49), an intermediate in the production of drugs and dyes, by a continuous catalytic process (Doraiswamy et al., 1981), compared to the usual high-pressure batch process from aniline, methanol, and sulfuric acid. In this process (reaction 6.43)... 

These were pyrolyzed directly in a 25-mL distillation flask fitted with a 3-in. Vigreux head. The sulfite was heated to 200°C under nitrogen at atmospheric pressure for 30 min. Vacuum (1 mmHg) was then applied, and the decomposition products were distilled slowly from the reaction mixture. The olefins were condensed in the air-cooled receiver, and the methanol and sulfur dioxide were allowed to pass into the dry ice trap. The yield of olefin was 86% from the cis isomer and 76% from the trans isomer.Analysis for the percentage of 1-substituted and 3-substituted cyclohexene was made by oxidation to the sulfones, and the position of the absorption maximum in the ultraviolet spectra was determined. The oxidized product from the cis isomer had an absorption maximum at 229 m u, corresponding to that of a mixture of 40% l-j -tolylsulfonyl-l-cyclohexene and 60% 3-p-tolylsulfonyl-i-cyclohexene. The oxidized product from the trans isomer had its absorption maximum at 232 m/z, corresponding to 80% of the 1-substituted isomer. 

Wherever the absorption or adsorption processes used to clean the gases have a high absorptivity for H2S but can eliminate COS only at high cost or not at all, the processes are designed in such a way that the sulfur contained in the gas reaches the gas purification unit in the form of H2S. Since, however, most modem gas purification units are capable of removing not only H2S but also COS and other organic sulfur components efficiently enough to meet the requirements for methanol production, COS hydrolysis is today used only in special cases. 

Depending on the temperatures at which the carbon monoxide is shifted, another distinction is made between high-temperature shift conversion (300-500 °C) and low-temperature shift conversion (180-280°C). Low- temperature shift conversion is, however, normally used only if the residual CO content in the converted gas has to be very low. As this is not the case fcx methanol production, and as there is no reason to put up with the high vulnerability to sulfur of the copper catalysts used for low-temperature conversion nor their considerable cost, the following description will be limited to high-temperature conversion. 

A gas produced by high-temperature gasification of a coal slurry [2.24], for instance, and containing some 10 % CO2, 45 % CO and 36 % H2 (in addition to sulfur components and a few inerts) could be shifted without any catalysts simply by quenching with water to obtain a syngas which would be appropriate for methanol production. To this end, 0.55 kg of water would have to be added to the raw gas containing some 0.4 kg of steam per m of gas at approximately 15(X) °C. The temperature of the mix would in this way be adjusted to approximately 950°C and about one fifth of the CO in the raw gas would be converted. The converted gas would then contain 32 % CO2, 19.5 % CO and 40 % H2 so that -after the CO2 has been washed out to approximately 3 % - the methanol synthesis gas will have a stoichiometric ratio of 2.07. 

As many types of coal contain little sulfur, but have a considerable surplus of carbon for methanol production, the H2S content of the resulting sour gases is frequently around or even less than 5 vol. %. Although the sulfur concentration can be increased in the gas purification section, this is always a costly undertaking. Certain direct treatment processes may therefore be used for such sulfur gases although they lead to sulfuric acid rather than to the more easily manageable and normally more conveniently marketable elemental sulfur. 

Synthesis of methyl methacrylate is fundamental to the production of the transparent plastic polymethyl methacrylate (PMMA), and is estimated at over two million metric tons per year. The monomer is most commonly synthesized via the well-established Acetone Cyanohydrin (ACN) process, as shown below, based on easily available raw materials such as, acetone, hydrogen cyanide, methanol and sulfuric acid. Reaction of acetone and hydrogen cyanide yields acetone cyanohydrin as an intermediate, which is then reacted with excess amount of concentrated sulfuric acid, followed by thermal cracking to form methacrylamide sulfate. The methacrylamide sulfate intermediate is then further hydrolyzed and esterified with aqueous methanol to form methyl methacrylate. 

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