A theoretical study of the dehydration of tertiary butanol in near-critical and supercritical water

Molecular dynamics simulations were performed to investigate the dehydration of tertiary butanol in water under ambient, near-critical and supercritical conditions. It was found that the equilibrium constant increased with temperature at a fixed pressure of 400 bar, favouring the dehydration reaction. This was mainly due to an increase in the entropy of reaction. The equilibrium was also favoured by low pressures. Studies of the solvation of isobutene gave an insight into how the hydrophobic effect varies with the state point of the water. It was seen that the solvation of isobutene becomes more favourable at higher temperatures due to the increasing entropy of solvation.