Acetic acid, synthesis

Benzo[c]furan, 1,3,4,7-tetraphenyl-steric hindrance, 4, 542 synthesis, 4, 683 Benzo[b]furan-3-acetic acid synthesis, 3, 686 Benzo[b]furan-3-amine, 2-acyl-tautomerism, 4, 648 Benzo[b]furan-2-carboxamides synthesis, 3, 685... 

In this reaction sequence acetic acid synthesis requires methyl transfer as CH3 to a Co(I)-corrin by N2 5-methyltetrahydrofolate monoglutamate to give a methylcorrinoid intermediate which is carboxylated to give a carboxymethylcorrinoid. This carboxymethylcorrinoid would then be reductively removed by NADPH to give acetic acid and regenerate the Co(I)-corrin. In contrast to the methyl-transfer proposed for the methionine synthetase reaction, this mechanism suggests that CH3-stabilized by Co attacks CO2 to give a carboxymethylcorrinoid intermediate. 

Acetic Acid Synthesis by Catalytic Carbonylation of Methanol... 

Haynes, A. (2005) Acetic acid synthesis by catalytic carbonylation of methanol, in Topics in Organometallic Chemistry, Vol. 18 (ed. M. Beller), Springer-Verlag, Berlin, pp. 179-205. 

Nevertheless, the critical role of the iodide fraction in ensuring a selective acetic acid synthesis is illustrated by the... 

Kinetic studies of the acetic acid synthesis catalyzed by RhCl3-3H20 have confirmed that the oxidative addition of Mel is the rate determining step.416"4 8 The effect of nitrogen and phosphorus ligands on the reaction has been studied, and bidentate ligands were shown to inhibit the reaction almost completely 419 A kinetic study of the solvent dependence of the reaction showed that... 

The carbonylation of methyl acetate to acetic anhydride is likely to become an industrial process in the near future 424,427 RhCl3-3H20 is typically used as catalyst precursor and an iodide promoter is used. A mechanistic study indicated that methyl iodide formed from the ester and HI is carbonylated as in acetic acid synthesis (Scheme 26). The resulting acyl, perhaps via reductive elimination of acetyl iodide, converts the acetic acid formed in the ester cleavage to acetic anhydride.428 430 [RhI(CO)(PPh3)2] also catalyzes the reaction though apparently more slowly than complex (95).430,431 The mechanism of this reaction is given in Scheme 27. 

As mentioned above in connection with the acetic acid synthesis, iridium complexes catalyze the water-gas shift reaction (equation 70). From IrCl3-3H20 and sulfonated derivatives of bipy and phen, water-soluble catalysts were obtained.444 Using dioxane as solvent, complexes of the type [Ir(cod)L2]+ (L= PMePh2, PPh3), [Ir(cod)L ]+ (L = diphos, phen, 4,7-Me2-phen, 4,7-Ph2-phen, 3,4,7,8-Me4-phen) and [Ir(cod)X] (X = 4,7-diphenylphenanthroline disulfonate) also catalyzed the reaction, with the anionic species being most active.470 The mechanism was thought... 

Butane from natural gas is cheap and abundant in the United States, where it is used as an important feedstock for the synthesis of acetic acid. Since acetic acid is the most stable oxidation product from butane, the transformation is carried out at high butane conversions. In the industrial processes (Celanese, Hills), butane is oxidized by air in an acetic acid solution containing a cobalt catalyst (stearate, naphthenate) at 180-190 °C and 50-70 atm.361,557 The AcOH yield is about 40-45% for ca. 30% butane conversion. By-products include C02 and formic, propionic and succinic acids, which are vaporized. The other by-products are recycled for acetic acid synthesis. Light naphthas can be used instead of butane as acetic adic feedstock, and are oxidized under similar conditions in Europe where natural gas is less abundant (Distillers and BP processes). Acetic acid can also be obtained with much higher selectivity (95-97%) from the oxidation of acetaldehyde by air at 60 °C and atmospheric pressure in an acetic acid solution and in the presence of cobalt acetate.361,558... 

Although the direct oxidation of ethane to acetic acid is of increasing interest as an alternative route to acetic acid synthesis because of low-cost feedstock, this process has not been commercialized because state-of-the-art catalyst systems do not have sufficient activity and/or selectivity to acetic acid. A two-week high-throughput scoping effort (primary screening only) was run on this chemistry. The workflow for this effort consisted of a wafer-based automated evaporative synthesis station and parallel microfluidic reactor primary screen. If this were to be continued further, secondary scale hardware, an evaporative synthesis workflow as described above and a 48-channel fixed-bed reactor for screening, would be used. 

Takaoka, S., "Acetic Acid Synthesis From Methanol and Carbon Monoxide", Report 37A, SRI Process Economics, March, 1973, pp. 83-107. 

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