Phase carbonylation

Propionic acid is accessible through the Hquid-phase carbonylation of ethylene over a nickel carbonyl catalyst (104), or via ethylene and formic acid over an iridium catalyst (105). Condensation of propionic acid with formaldehyde over a supported cesium catalyst gives MAA directiy with conversions of 30—40% and selectivities of 80—90% (106,107). Catalyst lifetime can be extended by adding low levels (several ppm) of cesium to the feed stream (108). 

Salmain, M., Fischer-Durand, N., Cavalier L., Rudolf, B., Zakrzewski, J., and Jaouen, G. (2002) Transition metal-carbonyl labeling of biotin and avidin for use in solid-phase carbonyl metallo immunoassay (CMIA). Bioconjugate Cbem. 13, 693-698. 

The SILP catalyst system was applied for water-free gas-phase carbonylation of methanol at two different gas space velocities, using a continuous... 

Grosjean, E., Grosjean, D., and Seinfeld, J.H. Atmospheric chemistry of 1-octene, 1-decene, and cyclohexane gas-phase carbonyl and peroxyacyl nitrate products. Environ. ScL Technol, 30(3) 1038-1047, 1996. 

Noziere, B. and Riemer, D.D. The chemical processing of gas-phase carbonyl compounds by sulfuric acid aerosols 2,4-pentanedione, Atmos. Environ., 27(6) 841-851, 2003. 

Vapor-Phase Carbonylation of Dimethyl Ether and Methyl Acetate with Supported Transition Metal Catalysts... 

It was found that a nickel-activated carbon catalyst was effective for vapor phase carbonylation of dimethyl ether and methyl acetate under pressurized conditions in the presence of an iodide promoter. Methyl acetate was formed from dimethyl ether with a yield of 34% and a selectivity of 80% at 250 C and 40 atm, while acetic anhydride was synthesized from methyl acetate with a yield of 12% and a selectivity of 64% at 250 C and 51 atm. In both reactions, high pressure and high CO partial pressure favored the formation of the desired product. In spite of the reaction occurring under water-free conditions, a fairly large amount of acetic acid was formed in the carbonylation of methyl acetate. The route of acetic acid formation is discussed. A molybdenum-activated carbon catalyst was found to catalyze the carbonylation of dimethyl ether and methyl acetate. 

We have already reported that nickel supported on activated carbon exhibits an excellent activity for the vapor phase carbonylation of methanol in the presence of methyl iodide (Mel) at moderate pressures (14-16). In addition, corrosive attack of iodide compounds on reactors is expected to be minimized in the vapor phase system. 

Rh- or Ir-exchanged heteropolyacids supported on Si02 catalyze vapor-phase carbonylation of methanol or dimethyl ether to give methyl acetate at 498 K and 1 atm (370). As shown in Table XXXIII, with RhPWi2O40/SiO2, the yield of methyl acetate is 44%. At this temperature, the yield of methyl acetate dropped rapidly to < 1 % during 6 h of reaction time accompanied by increases in the yields of dimethyl ether, methanol, and hydrocarbons. 

Manning DL, Maskarinec MP, Jenkins RA, et al. 1983. High performance liquid chromatographic determination of selected gas phase carbonyls in tobacco smoke. J Assoc Off Anal Chem 66 8-12. 

Heteropolyacids ion-changed with Group 8 metals, M[Wi2P04o] on silica, catalyze the gas-phase carbonylation of methanol or dimethyl ether to methyl acetate.76... 

Relative stability of the respective parent carbocations estimated from proton-transfer equilibria, in kcal mol po values in log unit of log(KIKo) for the gas-phase carbonyl basicity are obtained by multiplying the p values of the gas-phase basicities AAG(co) by a factor of 1000/2.303 7. ... 

It is reported that the two-phase carbonylation methodology has been used on a pilot plant scale by Montedison [31 ] for the conversion of benzyl chloride to phenylacetic acid for use in perfume constituents and pesticides (eq. (8)). The carbonylation is run in a biphasic medium employing diphenyl ether and aqueous 40 % sodium hydroxide as solvents. The catalyst system consists of a cobalt carbonyl complex and a benzyltrialkylammonium surfactant. The reaction takes place at low temperature and CO pressure, while benzyl chloride is added continuously to the reaction mixture. 

In the first work on the PTC carbonylation of organohalides, Pd(PPh3)4 was used as a metal catalyst [110]. There are a number of other examples of the use of Pd° complexes in two-phase carbonylations. The selective formation of one of four possible products, including esters, depends mainly on the composition of the metal complex (e. g., Pd(PPh3)4 vs. Pd(dba)2) [129]. Radical intermediates may be involved in the formation of several of the products. Esters (e. g., benzyl phenylacetate from benzyl bromide) are the major products of the carbonylation of benzyl bromides using a zwitterionic rhodium catalyst [130]. 

The vapor phase carbonylation of methanol to acetic acid with a nickel on active carbon catalysts was greatly enhanced by addition of hydrogen although 1 ittle hydrogen was incorporated in the products. 

Liquid phase carbonylation of methanol to acetic acid with a rhodium complex catalyst is a well known process (ref. 1). The authors have found that group 8 metals supported on carbonaceous materials exhibit excellent activity for the vapor phase carbonylation of methanol in the presence of iodide promoter(ref. 5). Especially, a nickel on active carbon catalyst gave acetic acid and methyl acetate with the selectivity of 95% or higher at 100% methanol conversion under 10 atm and 250 °C. In the present study it has been found that a small amount of hydrogen which is always contained in the commercially available CO and requires much cost for being removed completely, accelerates greatly the carbonylation reaction. 

Grosjean, D., E.L. Williams II, and J.H. Seinfeld. 1992. Atmospheric oxidation of selected terpenes and related carbonyls gas-phase carbonyl products. Environ. Sci. Technol. 26 1526-1533. 

Another way of avoiding less economical and toxic phosgene involves the use of dimethyl carbonate for the production of isocyanates and polycarbonates. In Japan, Ube have operated the first pilot plant for the highly selective gas-phase carbonylation of methanol. Further liquid-phase processes for the production of dimethyl carbonate are in operation at Daicel and Mitsui Sekka. 

Scheme 6.33 An example of multi-phase carbonylation reactions performed under continuous flow.

A rare example of a vapor-phase carbonyl condensation reaction leading to a double heteroatom five-membered ring system involves the production of 4-methylthiazole (28). This compound is a precursor to thiabendazole, a fungicide used to protect citrus fruit (ca 300 tons is consumed annually). The 4-methylthia-zole process is reported to use CS2SO4-doped zeolite MFI [53]. 

Modifications of gas chromatographic methods to determine vapor-phase carbonyl compounds in cigarette MSS continued for more than three decades, for example, see Miyake and Shibamoto (2564). 

Determination of vapour-phase carbonyls by high pressure bquid chromatography J. Liq. Chromatog. 4 (1981)... 

Carbon monoxide carbonylates methane at 573-673 K in the presence of nitrous oxide on a rhodium-doped iron phosphate catalyst to produce methyl acetate [88a]. Vapor-phase carbonylation of toluene yields p-tolualdehyde, which can be easily oxidized to terephthalic acid [88b]. 

Successful application of the SILP concept has also been achieved in continuous gas-phase carbonylation of methanol using a Monsanto-type catalyst system that contains the catalytically active species as the IL anion, impressively demonstrating the high efficiency of the thin IL catalyst phase. 

Liquid-Phase Carbonylation. An incentive for the development of immobilized solid catalysts in liquid-phase carbonylation is to retain the chemical characteristics of the soluble industrial catalysts (6) in the Reppe reaction and reduce the problems of corrosion as well as the separation of catalyst from reaction liquor. Various supporting materials such as active carbon, polymers, zeolites, and amorphous inorganic oxides are used to immobilize homogeneous carbonylation catalysts. 

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