Methanol converters

Fig. 7. Methanol converter types (a) quench, (b) multiple adiabatic, (c) tube-cooled, and (d) steam-raising.

This derivative is stable to TsOH/benzene at reflux and to Cr03/H. It is also stable to NBS/hv In the formation of a related derivative, formaldehyde from formalin (containing methanol) converted a C,-hydroxyl group to the C -methoxymethyl ether. Paraformaldehyde can be used as a source of methanol-free formaldehyde to avoid formation of the ethers. ... 

Gyclocondensation of diazomalonaldehyde 336 with 4-fluoroaniline carried out in methanol-acetic acid provides l-(4-fluorophenyl)-l,2,3-triazole-l-carbaldehyde 337 in 78% yield. Oxidation with MnOz in the presence of sodium cyanide in methanol converts aldehyde 337 into methyl ester 338 with 79% yield. Hydrazide 339 (84% yield) is obtained in a reaction of ester 338 with hydrazine. Product 339 reacts with various aromatic aldehydes to give hydrazones possessing interesting antiplatelet activity (Scheme 53) <2003BMC2051>. 

Heated in methanol for an extended period of time, propargyl azide 1147 experiences a [3,3] sigmatropic shift to allenyl azide 1148 that undergoes rapid cyclization to triazafulvene 1149. Addition of a molecule of methanol converts reactive intermediate 1149 to triazole 1150 that is isolated in 68% yield. In concentrated solutions, two molecules of intermediate 1149 may undergo cycloaddition to form dimer 1151 as a side product (Scheme 189) <2005EJ03704>. 

Methanol conversion, in formaldehyde manufacture, 12 115 Methanol converters, 16 308 Methanol-formaldehyde-water solutions, 12 109... 

P-Phenethylbiguanide is reported 602) to be resistant to methylation but as it behaves generally somewhat anomalously, e.g. in its stabihty towards acids (Section VII C), this provides no information as to the general behaviour of biguanides on alkylation. Thus, methyl iodide in methanol converted p-phenethylbiguanide merely into its hydriodide, and similar results were observed with methyl tosylate, and benzyl bromide. 

GRAMS METHANOL CONVERTED UNTIL METHANOL BREAK THROUGH PER GRAM OF HZSM5 (CATALYST LIFE TIME)... 

One of the most important considerations in designing a process for converting methanol to olefins was to find the best way to remove the considerable heat of reaction. Despite the fact that we are stopping the reaction at the intermediate olefin product, the reactions leading to these intermediates give off almost 90% of the heat released in the overall MTG reaction scheme (49 vs. 56 kJ/mole of methanol converted for MTO vs. MTG). Efficient removal of the heat of reaction is one of the main reasons a fluid-bed reactor was selected for scale-up demonstration. A second advantage of the fluid-bed is that product composition can be kept constant, since optimum catalyst activity can be maintained by continuous make-up and regeneration. 

This report describes a process to produce vinyl acetate with high selectivity from exclusively methanol, carbon monoxide, and hydrogen. The simplest scheme for this process involves esterifying acetic acid with methanol, converting the methyl acetate with syn gas directly to ethylidene diacetate and acetic acid, and finally, thermal elimination of acetic acid. Produced acetic acid is recycled. Each step proceeds in high conversion and selectivity. 

The acetoxy group of 9-(l-acetoxyethyl)carbazole is easily displaced with alcohols. Easy displacement of a similarly situated halogen can be achieved, as has been noted before (see Section II,C,2) thus methanol converts 9-(l-chloro-2-iodoethyl)carbazole to 9-(2-iodo-l-methoxyethyI) car-bazole. Elimination of acetic acid or ethanol by strongly heating 9-(l-acetoxyalkyl)- or 9-(l-ethoxyalkyl)carbazoles gives 9-vinylcarbazoles. In the absence of acid, ( )-alkenes are produced, but acid catalysis leads to a mixture of E and Z isomers. Acetyl chloride in pyridine also effects ethanol elimination. ... 

Methanol converts 106 to 107 under basic conditions (Scheme 25)23 a mechanism has been suggested.24... 

Peracids can oxidize 2//-imidazoles to A -oxides and N,N -dioxides, and sometimes to imidazoli-nones. Lead dioxide in methanol converts 2//-imidazole 1,3-dioxides into stable nitroxide radicals (96CHEC-II(3)146). 

A novel entry to decahydrocyclopentacyclooctene derivatives via the intramolecular photocycloaddition of fused a,/3-unsaturated y-lactones has been developed (80CC1011). Irradiation of the butenolide (153) in acetone solution gave both the fused and bridged photoadducts (154) and (155) (2-3 1). The major adduct was hydrolyzed, oxidized and esterified to afford (156). Reductive cleavage of the unsaturated keto ester (156) with lithium in ammonia afforded a five-component mixture of a,/3- and /3,y-unsaturated esters. Equilibration with 0.1M sodium methoxide in methanol converted the mixture into a single a,j8-unsaturated ester (157 Scheme 34). This annelative two-carbon ring expansion method may find application in the synthesis of ophiobolin and ceroplastol sesterterpenes. 

A problem of stannylene procedures, which has not yet found a uniformly satisfactory solution, is the disposal of the tin by-products, which are insoluble in water. In a few very favorabla cases, treatment with methanol converted them to the crystalline compound Br-BUjSn-O-SnBUj-OH, which could be removed by filtration. In the other cases, silica gel column chromatography is always successful. The highly lipophile, dibutyltin compounds move to the front in nonpolar eluents. However, chromatography is a great inconvenience in large-scale work. 

Arylmethyl chlorides or bromides are quite reactive compounds that are readily available or easily prepared, and as a result they are useful intermediates for the synthesis of other side-chain derivatives. Thus phenylmethyl chloride can be hydrolyzed to phenyl methanol, converted to phenylethanenitrile with alkali-metal cyanides, and oxidized to benzenecarbaldehyde (benzaldehyde) ... 

Both NBS and NCS in methanol converted 1-methyl- and 1-phenyl-l//-azepin-3(2//)-ones into the 4-mono- or 4,5-di-halogenated products, depending on the molar ratio of reagent to substrate. Product yields varied between 41 and 60% (90JHC3163). 

Methylation experiments using acidic methanol converted pretazettine into a mixture of a- and /3-O-methylpretazettine (252) having slightly different Rt on (TLC) but showing a single signal for benzylic proton in the NMR. It was concluded that pretazettine exists in solution as a mixture of C-8 epimers although the protons of the C-8 epimers must have equivalent chemical shifts. 

Methanol converter two stainless steel columns, in series, operating at 300°C and 50 atm, Cu catalyst. C02 removal unit made of carbon steel, operates with 5°C water in spray. Electric gas heater C - Services... 

When the most economical mode of operation is to send the H2 to the methanol converter, and when C02 is available (being captured from some external fossil source such as a coal-burning power plant), each mol of C02 will require 3 mol of H2 to generate 1 mol of methanol (CH3OH). Therefore, in that mode of operation, the amount of H2 sent to the methanol converter (FT-30) is ratio-controlled by FFC-30 proportioning the H2 flow to match the flow of C02 (FT-34). 

It was found in this experiment that both anionic and cationic species reacted efficiently with methanol in bulk styrene. The bonded dimer cations and the radical anions were converted to long-lived benzyl radicals, which initiated the radical polymerization. The G value of the propagating benzyl radical was only 0.7 in pure styrene, but it increased up to 5.2 in the presence of methanol. A small amount of methanol converted almost all the charge carriers to propagating free radicals this explains why the mechanism of radiation-induced polymerization is changed drastically from cationic to radical processes on adding methanol. 

The transformation was called an homologation reaction because essentially it consisted in going from one alcohol to an alcohol containing one carbon atom more than the starting material (Wender, Levine, and Orchin, 14). Tertiary alcohols reacted most rapidly, secondary alcohols less rapidly and primary alcohols only very slowly. It was of considerable importance to ascertain whether the olefin intermediate was essential and for this purpose, methanol and benzyl alcohol, neither of which can dehydrate to an olefin, were used in the reaction. Both compounds, contrary to other primary alcohols, reacted quite rapidly and gave the homologous alcohol of the methanol converted, about 40 mole per cent went to ethanol and with benzyl alcohol, a 30% yield of 2-phenylethanol was secured. In both examples, however, reduction products were also present of the methanol converted, 8 mole per cent went to methane and from benzyl alcohol, a 50 to 60% yield of toluene was secured. The conversion of methanol to methane appears to be the only case in which an appreciable quantity of hydrocarbon is secured from a purely aliphatic alcohol. The behavior of benzyl alcohol and its derivatives will be discussed later. 

Synthetic routes to trans-verbanone are discussed,308 and mercuric acetate in boiling methanol converts /3-pinene into a 65 35 mixture of the myrtenol ether (212 R = Me) and the trans-pinocarveol ether (213 R = Me).309... 

Description Gas feedstock is compressed (if required), desulfurized (1) and sent to the optional saturator (2) where some process steam is generated. The saturator is used where maximum water recovery is important. Further process steam is added, and the mixture is preheated and sent to the pre-reformer (3), using the Catalytic-Rich-Gas process. Steam raised in the methanol converter is added, along with available C02, and the partially reformed mixture is preheated and sent to the reformer (4). High-grade heat in the reformed gas is recovered as high-pressure steam (5), boiler feedwater preheat, and for reboil heat in the distillation system (6). The high-pressure steam is used to drive the main compressors in the plant. 

II) A typical synthesis loop will consist of a circulator (3), the methanol converter (4), heat recovery and coolers and a methanol separator (5). The methanol synthesis catalyst is copper-based and works at pressures between 50 to 100 bar and temperatures between 200°C and 290°C. Larger plants have an operating pressure range of 80 to 100 bar. 

This new selective metalation reaction is useful for synthesis of 10-substituted limo-nene derivatives. The excess limonene is readily separated from the product by fractional di.stillation. Thus metalation of (-i-)-limonene (3) followed by reaction with carbon dioxide and then esterification affords the 3,v-unsaturated ester (5) in 19% yield. Isomerization with sodium methoxide in methanol converts (5) into the conjugated isomer (6). 

These spirodioxindole lactones are opened by methanol, but not by ethanol, to yield methyl ester derivatives of dioxmdole-3-propionic acid. This reaction proceeds even at room temperature in aqueous methanol. Refluxing anhydrous methanol converts the lactone of 5-bromodioxindole-3-propionic acid (m.p. 200.5°C) to the ester (m.p. 118°C) within 1-2 hr. The use of methanol in the cleavage of water-insoluble peptides, such as... 

The reactions of compounds containing one nitrate group at Cl, C2, or C6 have been compared with those of the corresponding halides and sulfonate esters. Barium carbonate in boiling methanol converts 2,3,4,6-... 

We studied hydrocarbon synthesis from CO2 using Cu-Zn-Cr (3 3 1)/HY and Fe-ZnO /HY composite catalysts[2 6]. In this case, first CO2 converted to methanol, and then methanol converted to hydrocarbon over zeolite. The main products formed among hydrocarbons was ethane, propane and butane, and hydrocarbon distribution was different from Schulz-Anderson-Flory rule. In MTG reaction, methanol converted to dimethyl ether, then to ethene, and ethene converted to higher hydrocarbons or ethane. In order to obtain higher hydrocarbons, it is important to find active catalysts which have no hydrogenation activity of olefin. 

At reflux, the action of 3 equivalents of mercury(II) chloride in methanol converts the diethyl dithioacetal of D-glucose into a 5 1 mixture of methyl /3- and a-D-glucopyranoside299 extension of this reaction to the dibenzyl dithioacetal s of L-arabinose, L-rhamnose, and D-galactose afforded, as major products, the methyl /3-l-pyranoside of the L-pentose and the methyl a-pyranosides of the two hexoses, respectively.300... 

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