Promoters nickel-catalyzed methanol

Nickel carbonyl charged, or formed in the carbonylation reaction mixture, can catalyze the carbonylation of methanol (11). To maintain the activity of the nickel carbonyl catalyst high temperature and pressure are required (12-14). However, certain promoters can maintain an active, soluble, nickel carbonyl species under much milder conditions. The most reactive promoters are phosphines, alkali metal salts, tin compounds, and 2-hydroxypyridine. Reaction rates of 2 to 7 X 10-3(mol/1.sec) can be achieved without the use of high concentration of iodine (Table II). in addition, high reaction rates... 

Iridium supported on active carbon was found to be less active than rhodium but more active than nickel (33). Methyl chloride is less efficient but still a moderate promoter in the Ir/C-catalyzed vapor-phase carbonylation of methanol... 

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