Ethanol is manufactured globally either by the fermentation of glucose or by the direct hydration of ethene.
Which statement regarding these two production methods is correct?
The direct hydration of ethene is a batch process with a 100%100\%100% atom economy, operated at high temperatures and pressures.
Fermentation is carried out under anaerobic conditions at approximately 35 ∘C35\ ^\circ\text{C}35 ∘C to prevent yeast enzymes from denaturing and to avoid aerobic respiration which does not yield ethanol.
The fermentation of glucose has a higher atom economy than the direct hydration of ethene because it produces carbon dioxide as a useful co-product.
The direct hydration of ethene is catalysed by concentrated sulfuric acid at a temperature of 300 ∘C300\ ^\circ\text{C}300 ∘C and a pressure of 65 atm65\text{ atm}65 atm.