Acetic acid manufacture

Liquid-Phase Oxidation. Liquid-phase catalytic oxidation of / -butane is a minor production route for acetic acid manufacture. Formic acid (qv) also is produced commercially by Hquid-phase oxidation of / -butane (18) (see HYDROCARBON OXIDATION). 

Acetic Acid. Manufacture of acetic acid [64-19-7] by homogeneous catalytic methanol carbonylation has become the leading commercial route to acetic acid (eq. 8) (34,35). 

Considerable challenges still remain in the development of new carbonylation processes for acetic acid manufacture. For example, all of the current processes use iodide compounds, leading to corrosive HI and the need for expensive materials for plant construction. An iodide-free system could potentially impart considerable benefit. Other long term goals include the selective direct conversion of syn-gas or oxidative carbonylation of methane to acetic acid. Organometallic chemists are certain to play a crucial role if these targets are to be achieved. 

The third and now preferred method of acetic acid manufacture is the carbonylation of methanol (Monsanto process), involving reaction of methanol and carbon monoxide (both derived from methane). This is discussed in Chapter 12, Section 3. 

Although we have included acetic acid manufacture under ethylene derivatives, as you can see it is made from three of the seven basic organics ethylene, C4 hydrocarbons, and methane, with the most important method being from methane. Pure 100% acetic acid is sometimes called glacial acetic because when cold it will solidity into layered crystals similar in appearance to a glacier. It is a colorless liquid with a pungent, vinegar odor and sharp acid taste, bp 118°C, and mp 17°C. 

Table 12.2 gives the uses for methanol. The percentage of methanol used in the manufacture of formaldehyde has been fluctuating. It was 42% in 1981. It has decreased in part because of recent toxicity scares of formaldehyde. The percentage of methanol used in acetic acid manufacture is up from 7% in 1981 because the carbonylation of methanol has become the preferred acetic acid manufacturing method. MTBE is the octane enhancer and is synthesized directly from isobutylene and methanol. It was... 

Conversion of ethylene to acetaldehyde with a soluble palladium complex was one of the early applications of homogeneous catalysis. Traditionally, acetaldehyde was manufactured either by the hydration of acetylene or by the oxidation of ethanol. As most of the acetic acid manufacturing processes were based on acetaldehyde oxidation, the easy conversion of ethylene to acetaldehyde by the Wacker process was historically a significant discovery. With the... 

Several C-labelled tetraphenyl arsonium salts of Rh(III) containing complex anions have been synthesized to investigate, by the N.M.R. method, the mechanism of the rhodium/iodine-catalysed industrial carbonylation of methanol used for acetic acid manufacture. A revised catalytic cycle for the reaction has been proposed (equation... 

Carbonylation with homogeneous nickel catalysts was very extensively studied by Reppe in the thirties and forties. This work was not published until 1953. Based on these results, an acetic acid manufacturing process was commercialised in 1955. 

Through study of the mechanism by which the catalyzed liquid-phase oxidation of acetaldehyde to acetic proceeds, it has been found, that at temperatures below 15 C and in suitable solvents the acetaldehyde forms an unstable compound, acetaldehyde monoperacetate. At controlled low temperatures this compound can be made to yield peracetic acid and acetaldehyde. Salts of the metals cobalt, copper, and iron catalyze the first-stage reaction, in a manner used in acetic acid manufacture. 

Although the term methanol carbonylation is usually associated with acetic acid manufacture, an alternative carbonylation pathway involves base-catalyzed addition of CO to alkoxide ions to provide a simple route to formate esters (see also the section Direct Synthesis of Methanol from CO/H2). In the case of methanol as the alkanol, the reaction is carried out industrially on a large scale to produce formic acid. The reaction proceeds at ca 30 bar and 80°C using sodium or potassium methoxide as the catalyst and involves nucleophilic attack of methoxide on CO ... 

Fig. 25.9 The two interrelated catalytic cycles in the Monsanto (M = Rh) and Cativa (M = Ir) acetic acid manufacturing processes.

Stull, Westrum, and Sinke devote a chapter to the discussion of the applications of thermodynamics to industrial problems. Subjects covered include the petroleum industry, chemicals from methane, styrene manufacture, acrylonitrile and vinyl chloride syntheses, methanol synthesis, formaldehyde production from methanol, acetic acid manufacture, the Gatterman-Koch reaction, and catalyst selection. 

In comparison to other acetic acid manufacturing processes, hydrocarbon oxidation uses very cheap raw materials, but isolation of the product is complicated and expensive. Apart from dealing with the large number of by-products, the separation of acetic acid from the water formed during oxidation is a major task that requires azeotropic distillation with entrainment agents. 

Busche RM (1985) Acetic acid manufacture - fermentation alternatives. In Cherenisinoff PN, Ouellette RP (eds) Biotechnology applications and research technomic. Technomic Lancaster PA, pp 88-102 Busche RM (1991) Extractive fermentation of acetic acid economic tradeoff between yield of dostridium and conantration of acetobacter. Appl Biochem Biotechnol 28(29) 605—621... 

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