New catalyst complexes of acetic acid synthesis from methanol carbonylation reaction: A Review
A Research by: Mohammad Shareie, Sara Zilabi, Abdolah Chehrazi, Mehdi Tajjadod
Acetic acid has been used as a significant reactant in some chemical processes. Furthermore, it is utilized as a solvent for the synthesis of precious components. Methanol Carbonylation is one of the production methods of acetic acid. Methanol carbonylation reaction has been noticeably studied by using homogeneous and heterogeneous catalysts. In addition, some different supporting materials such as carbon active, clay, alumina, silica, zeolite, or other adsorbents have been recently investigated for developing the effective heterogeneous catalysts. For the determination of the effects of liquid-phase catalysts, several commercialized homogeneous catalysts have been reported for the synthesis of acetic acid by methanol carbonylation, which includes, metal-organic complexes such as cobalt, ruthenium, iridium, nickel, or rhodium-based homogeneous catalysts. Although the use of homogeneous rhodium or iridium complexes in the acetic acid industry is high efficiencies, arguably the use of heterogeneous catalysts has preponderance such as easy separation that leads to less catalyst waste. As a result, various materials such as activated carbon, clay, alumina, silica, and zeolite have been survived as a catalytic base for the development of acetic acid heterogeneous catalysts. Moreover, the influences components which have been used for the carbonylation of methanol in the liquid or vapor phase are Zeolite, nickel, copper, gold, platinum, palladium, osmium, copper-nickel, copper-Mordenite, palladium-cerium, ruthenium-rhodium, and lanthanum-rhodium. It is inevitable that, modification of a rhodium-based homogeneous catalyst with the addition of ligands is another way to increase catalytic activity. Phosphine ligands and their derivatives have received more attention in studies. The present paper summarizes commercialized chemical processes with rhodium and iridium-based catalytic systems in a liquid-phase carbonylation reaction such as Monsanto, Cativa, Acetica, as well as a number of alternative catalytic systems including heterogeneous catalysts to solve some process issues such as insufficient separation of homogeneous catalysts from a corrosive liquid-phase reaction medium. It was found that homogeneous complexes containing phosphorus ligands and zeolites as catalyst support are promising systems in the production of acetic acid.
Keywords: Acetic acid, Methanol carbonylation, Monsanto process, Rhodium complexes, Heterogeneous and Homogeneous catalysts
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