Acetic acid synthesis, carbonylation methanol

Various unsaturated compounds can be inserted into the metal alkyl, aryl, and alkenyl complexes to give new organometallic complexes having various functional groups. The insertions of carbon monoxide (CO) and isocyanide (CNR) into transition metal-carbon a-bond are particularly important processes, since a carbon unit can be increased in the process and the acyl type complexes formed by the insertion processes can be subjected to further transformations to synthesize useful organic compounds. For example, the CO inserhon constitutes a fundamental step in industrially important processes such as hydroformylation of olefins, acetic acid synthesis from methanol and CO, Fischer-Tropsch process, amidocarbonylation, olefin and CO copolymerizahon processes as well as in a variety of laboratory syntheses of carbonyl containing compounds. 

Actual operating capacities of Reppe carbonylation processes are difficult to estimate since only a few data are available in the literature. However, it is known that some of the syntheses are carried out on an industrial scale, e. g. the synthesis of acrylates from acetylene, carbon monoxide and alcohols (BASF) [1004, 1005], the acetic acid synthesis from methanol and carbon monoxide and the synthesis of higher molecular weight saturated carboxylic acids from olefins, carbon monoxide and water. Propionic acid (30,000 tons/year) and to a smaller extent heptadecanoic dicarboxylic acid are manufactured via the carbonylation route at BASF. Butanol is made from propylene in Japan [1003, 1004]. 

Acetic Acid and Anhydride. Synthesis of acetic acid by carbonylation of methanol is another important homogeneous catalytic reaction. The Monsanto acetic acid process developed in the late 1960s is the best known variant of the process. 

Acetic Acid Synthesis by Catalytic Carbonylation of Methanol... 

Torrence P (2002) Carbonylations synthesis of acetic acid and acetic acid anhydride from methanol. In Cornils B, Herrmann WA (eds) Applied homogeneous catalysis with organometallic compounds, vol 1, 2nd edn. Wiley, Weinheim, p 104... 

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. 

The synthesis of acetic acid (AcOH) from methanol (MeOH) and carbon monoxide has been performed industrially in the liquid phase using a rhodium complex catalyst and an iodide promoter ( 4). The selectivity to acetic acid is more than 99% under mild conditions (175 C, 28 atm). The homogeneous rhodium catalyst is also effective for the synthesis of acetic anhydride (Ac O) by the carbonylation of dimethyl ether (DME) or methyl acetate (AcOMe) (5-13). However, rhodium is one of the most expensive metals, and its proved reserves are quite limited. It is highly desirable, therefore, to develop a new catalyst as a substitute for rhodium. 

This direct, oxidative condensation of methane to acetic acid in one-pot could be competitive with the current three-step, capital intensive process for the production of acetic acid based on methane reforming to CO, methanol synthesis from CO, and generation of acetic acid by carbonylation of methanol. Key improvements required with the PdS04/H2S04 system, however, will be to develop more stable, faster, and more selective catalysts. Although it is possible sulfuric acid could be utilized industrially as a solvent and oxidant for this reaction, it would be desirable to replace sulfuric acid with a less corrosive material. This chemistry has recently been revisited, verified, and extended by Bell et al., who used Cu(II)/02 as the oxidizing system [22],... 

Haynes A (2006) Acetic Acid Synthesis by Catalytic Carbonylation of Methanol. 18 He Y, see Nicolaou KC (1998) 1 73-104... 

Another important and commercially essential example proving the variability of homogeneous catalysis is the synthesis of acetic acid via carbonylation of methanol. Here, too, a breakthrough was achieved by employing milder reaction... 

In addition, acetic acid synthesis from methane alone was also achieved in the presence of catalytic PdS04 using sulfuric acid as the reaction medium. The stoichiometry of the reaction is summarized in equation (43). TON (CH3C02H/Pd) of 4.1 was achieved under the conditions of equation (44). i C-labeling experiments demonstrated that both the methyl group and the carbonyl groups of acetic acid come from methane (Scheme 3). Methanol is rapidly converted to CO, which further reacts with methyl palladium species to give acetic acid (66,67). The mechanism is closely related to the results of C-labeld experiments in methane carbonylation (eq. (34)). 

Catalytic Carbonylation of Methanol 12.4.1 Monsanto Acetic Acid Synthesis... 

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