ETHYLENE GLYCOL

Ethylene glycol could be produced directly from synthesis gas using an Rh catalyst at 230°C at very high pressure (3,400 atm). In theory, five moles synthesis gas mixture are needed to produce one mole ethylene glycol:

Other routes have been tried starting from formaldehyde or paraformaldehyde. One process reacts formaldehyde with carbon monoxide and H₂ (hydroformylation) at approximately 4,000 psi and 110°C using a rhodium triphenyl phosphine catalyst with the  intermediate formation of glycolaldehyde. Glycolaldehyde is then reduced to ethylene glycol:

The DuPont process (the oldest syngas process to produce ethylene glycol) reacts formaldehyde with CO in the presence of a strong mineral acid. The intermediate is glycolic acid, which is esterified with methanol. The ester is then hydrogenated to ethylene glycol and methanol, which is recovered. The net reaction from either process could be represented as: