Acetic acid, conversion methanol

In homogeneous catalytic systems we witnessed a new process for the production of acetic acid from methanol and carbon monoxide using a transition metal complex, thus displacing the earlier process employing ethylene as the starting material. The use of immobilized enzymes makes possible the commercial conversion of glucose into fructose. 

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. 

Dziewinski et al. [71] have reported current efficiencies greater than 90% at 80°C for isopropanol, acetone, and acetic acid, whereas methanol, chloroform, and carbon tetrachloride were converted into carbon dioxide at room temperature with ca. 100% current efficiency. The predicted order of ease of oxidation is alcohols < aldehydes, ketones < carboxylic acids. Thus, the complete conversion to carbon dioxide, in particular for large organic molecules, is expected only at elevated temperatures. To avoid the use of a separator, Farmer et al. [72,75] employed C0SO4 in sulfuric acid. A scheme of the system is shown in Fig. 17. Both electrodes, the anode and the cathode, are usually of a Pt-containing surface layer, although other materials such as Au, steel, graphite, Ti, Nb, Ir, or tin oxide can also be used. H2 is evolved at the cathode because the deposition of the mediator takes place... 

When 7-aeyl-7 -reserpine derivatives (XV) are refluxed in dilute methanol with a few drops of acetic acid, conversion into the corresponding oxindole (XIX) with concomitant formation of the five-membered spiro-ring C takes place. Under these conditions, also, carbon... 

The main large-scale metal catalyzed reactions involving addition of CO (rather than CO + H2) to an organic substrate are the manufacture of acetic acid from methanol and the related production of acetic anhydride from methyl acetate. The syntheses of some other carboxylic acids and the conversion of a substituted benzyl alcohol to ibuprofen involve similar reactions. 

Methylacetate has an EHI of 0.67 and thus, ordinarily, would also be considered difficult to process. Its net hydrogen content, however, is substantially higher than that of acetic acid. Because of its higher carbon content (48.6% C), and despite decarboxylation and coking reactions, the observed hydrocarbon yield remains comparable to that of methanol. Moreover, hydrocarbon selectivity for direct conversion to 0-+ gasoline is higher than acetic acid or methanol. Thus,... 

The initial step of methanol conversion is composed of carbonylation to methyl acetate and dehydration to DME in parallel (see scheme below). DME is successively carbonylated to form methyl acetate. Methyl acetate is further carbonylated to acetic anhydride, which is rapidly hydrolyzed to acetic acid. Hydrolysis of methyl acetate to acetic acid and methanol proceeded also on the carbon support. Thus, carbonylation of methanol proceeds through a set of parallel and series reactions that produce methyl acetate and DME as primary products with acetic acid as the ultimate product, according to following reaction pathways (32,33) ... 

Researchers at the Pennsylvania State University have reported direct catalytic conversion of methane into acetic acid under relatively mild conditions. Conventional synthesis of acetic acid from methanol currently involves a three stage process, including ... 

In these experiments, the concentrations of reactants and products at the exit of the reactor were observed under steady state conditions for different liquid velocities and molar ratio of reactants in a temperature range of 298 - 363 K. Typical results are shown in Fig. 5.1 for acetic acid-methanol system. For acetic acid with butanol and maleic acid with methanol esterification the results are shown in Fig 5.2 and 5.3 respectively. From these data the conversion of acid as a function of liquid velocity was also evaluated for all the systems. For example, the acetic acid conversion obtained for esterification with methanol is presented in Fig. 5.4 and 5.5 for 318 and 328 K respectively. 

The conversion of acetic acid obtained for acetic acid with methanol esterification is shown in Fig. 5.6 for different liquid velocities and mole ratios. As expected the conversion falls with increase in velocity. The agreement with model predictions and experimental data for different reactant concentration was very good. 

METHOD 2 [89]--1M MDA or benzedrine and 1M benzaldehyde is dissolved in 95% ethanol (Everclear), stirred, the solvent removed by distillation then the oil vacuum distilled to give 95% yellow oil which is a Schiff base intermediate. 1M of this intermediate, plus 1M iodomethane, is sealed in a pipe bomb that s dumped in boiling water for 5 hours giving an orangy-red heavy oil. The oil is taken up in methanol, 1/8 its volume of dH20 is added and the solution refluxed for 30 minutes. Next, an equal volume of water is added and the whole solution boiled openly until no more odor of benzaldehyde is detected (smells like almond extract). The solution is acidified with acetic acid, washed with ether (discard ether), the MDMA or meth freebase liberated with NaOH and extracted with ether to afford a yield of 90% for meth and 65% for MDMA. That s not a bad conversion but what s with having to use benzaldehyde (a List chemical) Strike wonders if another aldehyde can substitute. 

Commercial production of acetic acid has been revolutionized in the decade 1978—1988. Butane—naphtha Hquid-phase catalytic oxidation has declined precipitously as methanol [67-56-1] or methyl acetate [79-20-9] carbonylation has become the technology of choice in the world market. By-product acetic acid recovery in other hydrocarbon oxidations, eg, in xylene oxidation to terephthaUc acid and propylene conversion to acryflc acid, has also grown. Production from synthesis gas is increasing and the development of alternative raw materials is under serious consideration following widespread dislocations in the cost of raw material (see Chemurgy). 

In 1968 a new methanol carbonylation process using rhodium promoted with iodide as catalyst was introduced by a modest letter (35). This catalyst possessed remarkable activity and selectivity for conversion to acetic acid. Nearly quantitative yields based on methanol were obtained at atmospheric pressure and a plant was built and operated in 1970 at Texas City, Tex. The effect on the world market has been exceptional (36). 

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. 

Aroclor 1248, Aroclor 1254, and Aroclor 1260. Quantitation is by comparison of chromatograms with standard concentrations of pure compounds treated in an identical manner. The phenoxy acid herbicides (2,4-dichlorophenoxy)acetic acid (2,4-D), sUvex, and (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) can be deterrnined by electron-capture detection after extraction and conversion to the methyl esters with BF.-methanol. The water sample must be acidified to pH <2 prior to extraction with chloroform. 

A Belgian patent (178) claims improved ethanol selectivity of over 62%, starting with methanol and synthesis gas and using a cobalt catalyst with a hahde promoter and a tertiary phosphine. At 195°C, and initial carbon monoxide pressure of 7.1 MPa (70 atm) and hydrogen pressure of 7.1 MPa, methanol conversions of 30% were indicated, but the selectivity for acetic acid and methyl acetate, usehil by-products from this reaction, was only 7%. Ruthenium and osmium catalysts (179,180) have also been employed for this reaction. The addition of a bicycHc trialkyl phosphine is claimed to increase methanol conversion from 24% to 89% (181). 

Eastman Chemical Company has operated a coal-to-methanol plant in Kingsport, Tennessee, since 1983. Two Texaco gasifiers (one is a backup) process 34 Mg/h (37 US ton/h) of coal to synthesis gas. The synthesis gas is converted to methanol by use of ICl methanol technology. Methanol is an intermediate for producing methyl acetate and acetic acid. The plant produces about 225 Gg/a (250,000 US ton/a) of acetic anhydride. As part of the DOE Clean Coal Technology Program, Air Products and Cnemicals, Inc., and Eastman Chemic Company are constructing a 9.8-Mg/h (260-US ton/d) slurry-phase reactor for the conversion of synthesis gas to methanol and dimethyl... 

Schemes 15 and 16 summarize the syntheses of intermediates that represent rings A and D of vitamin Bi2 by the Eschenmoser group. Treatment of lactam/lactone 51, the precursor to B-ring intermediate 8 (whose synthesis has already been described, see Scheme 8), with potassium cyanide in methanol induces cleavage of the y-lac-tone ring and furnishes intermediate 76 after esterification of the newly formed acetic acid chain with diazomethane. Intermediate 76 is produced as a mixture of diastereomers, epimeric at the newly formed stereocenter, in a yield exceeding 95%. Selective conversion of the lactam carbonyl in 76 into the corresponding thiolactam...

If the analyte contains either an acidic or a basic functionality, adjusting the pH of the extraction solvent to make the analyte either ionic or nonionic may be advantageous. To make an analyte that contains an acidic or basic functionality nonionic for extraction into a nonpolar solvent, a small amount (5% or less) of an organic acid (such as acetic acid or trifluoroacetic acid) or organic base (triethylamine) along with methanol (about 10%) can be added to diethyl ether or ethyl acetate. Conversely, buffered solutions can be used to control the pH precisely in such a way as to control the charge on an analyte and thus improve its extraction efficiency into polar solvents. 

Before discussing the results obtained from this study it is important to understand the method by which a measurement of conversion was obtained directly from the spectra acquired from the reaction being studied in situ. The reaction chosen for study was the esterification reaction of methanol and acetic acid to form methyl acetate and water ... 

It is important that in the two organic equilibria involving iodide reaction (Equation (2)) shows complete conversion of methanol to methyl iodide, whereas the reaction with acetyl iodide shows complete conversion to acetic acid and hydrogen iodide (Equation (3)) ... 

The hydrolysis of methyl acetate (A) in dilute aqueous solution to form methanol (B) and acetic acid (C) is to take place in a batch reactor operating isothermally. The reaction is reversible, pseudo-first-order with respect to acetate in the forward direction (kf = 1.82 X 10-4 s-1), and first-order with respect to each product species in the reverse direction (kr = 4.49 X10-4 L mol-1 S l). The feed contains only A in water, at a concentration of 0.050 mol L-1. Determine the size of the reactor required, if the rate of product formation is to be 100 mol h-1 on a continuing basis, the down-time per batch is 30 min, and the optimal fractional conversion (i.e., that which maximizes production) is obtained in each cycle. 

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