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Production of Ethanoic Acid - The Monsanto Process
| In 1966 Monsanto established that a rhodium based catalyst, with an iodide co-catalyst could give 99% selectivity based on methanol, and at milder conditions of 180oC and 30 atm. Greater selectivity means easier purification. |
| The process was commercialised as the Monsanto Process in 1970, and until 1996 was the basis of most new ethanoic acid production. The mechanism has been carefully studied. |
| 60% of the ethanoic
acid currently produced is made by reacting methanol with carbon monoxide
over a catalyst.
CH3OH
+ CO This reaction has a big advantage over earlier processes in that it has a theoretical atom economy of 100%, if a suitable catalyst can be found |
| BASF introduced the first commercial process in 1960 using a cobalt catalyst and iodide co-catalyst operating at 200oC and 700 atm. About 90% of the methanol is converted into ethanoic acid. |
A metal in the same group in the periodic table as Co, so Rh
Greater selectivity, and a catalyst that would work at lower temperatures and pressure.
|
Question The Monsanto process was a big improvement on the previous method which for every 100 tonnes of ethanoic acid gave 65 tonnes of by-products. Which other metal might make a good catalyst? What further improvements would you
look for with a new catalyst?
|
CH3COOH
