CIEC Catalysis -- Ethanoic Acid

why do we need ethanoic acid?

the monsanto process

mechanism of rhodium catalysed reaction

a commercial monsanto plant

the cativa process

mechanism of iridium catalysed reaction

the promoter

comparison of two catalysts

a commercial cativa plant

the cativa process in use

Simplified Flow Chart for a Commercial Monsanto Plant

They are in the same group, and so would be expected to have similar properties.

The major units which make up a commercial Monsanto plant for making ethanoic acid

Question

Why is it not possible to build the plant from stainless steel.

How many distillation columns are used, and for what purposes. Why does this greatly increase the cost of the product?

The reaction mixture is very corrosive, so special construction materials are needed.

Three distillation columns are used

1. to remove low boiling components (methanol is recycled, and low boiling impurities like methyl iodide are removed).

2. to remove water

3. to remove high boiling impurities like propanoic acid

In 1986 BP acquired Monsanto technology. In their original work the Monsanto group had noted that iridium also gave an effective catalyst and would make a more stable catalyst than rhodium. Further research and development at BP Saltend in Hull led to a new process using an iridium catalyst.

Question
Check the positions of Co, Rh, and Ir in the periodic table and relate this to their catalytic activity

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