The effect of salts on hydrolysis in supercritical and near-critical water: Reactivity and availability

Tuning alkylation reactions with temperature in near‐critical water

“…To ensure that no oxygen was present during the reactions, the water was first deoxygenated with nitrogen for at least 1 h before it was added to the reactor, and the headspace in the reactor was replaced with nitrogen. No significant wall effects have been observed in near-critical water when the stainless steel reactors were not new reactors (Torry et al, 1992;Kuhlmann et al, 19941, and all of the stainless steel reactors used in this investigation had been used previously.…”

Reactions at supercritical conditions: Applications and fundamentals

“…15) revealed that the transition state for guaiacol hydrolysis was more polar than the reactants and products. In a subsequent study, Torry et al (1992) found that the hydrolysis rate constant for dibenzyl ether and benzylphenyl amine initially increased with added salt, but subsequently decreased with higher salt loadings. This behavior was consistent with the added salt increasing the dielectric constant of the medium and hence the rate constant for hydrolysis, but also decreasing the number of water molecules available for hydrolysis by requiring water molecules to be solvated These competing effects produced the maximum rate observed.…”

“…Klein's group at the University of Delaware studied the reaction pathways, kinetics, and mechanisms of solvolysis and pyrolysis of coal model compounds in SC water and other SCFs (Lawson and Klein, 1985;Townsend and Klein, 1985;Klein, 1985, 1987;Townsend et al, 1988;Abraham et al, 1988;Huppert et al, 1989;Wu et al, 1989Wu et al, , 1991aKlein et al, 1990Torry et al, 1992;Boock et al, 1992). They examined the effects of temperature, solvent density, phase behavior, and added salts, and used transition-state theory to interpret their results.…”

Treatment of cotton printing and dyeing wastewater by supercritical water oxidation

“…2 we can see that, when compared with 100 or 300% excess oxygen, the effect of temperature on the TOC thermal degradation is very noticeable at 0% excess oxygen, and the TOC degradation efficiency varies from 17.46 to 93.98% with the temperature increasing from 400 to 600˚C, although it is very low at 400˚C due to no oxygen. It is very difficult to find out the reaction mechanism of our thermal degradation reactions because of complicated constitutions in the wastewater, but we know TOC in SCW can decompose or convert to other compounds via pyrolysis, hydrolysis, condensation reactions, and others [21][22][23]. It is the rate of above reactions increasing with the temperature that results in a tremendous raise in TOC conversion of the thermal degradation reaction since the richer TOC concentration are remained, while there is limited scope for the increment of TOC conversion in SCWO because there is already a high level of TOC conversion at low temperature.…”