A rational multiscale method is proposed for selecting an economical and sustainable solvent for the direct hydration of cyclohexene. At the molecular scale, liquid-liquid phase equilibrium was estimated using group contribution methods to rapidly screen the potential solvent candidates from a range of organics using a novel evaluation index. At the reactor scale, these candidates were experimentally investigated to pick out the solvents that could significantly improve the conversion, without introducing side reactions and deactivating the catalyst. At the process scale, the total annual cost and CO2 emission were calculated to evaluate the eco-efficiency. Using this new multiscale method, acetophenone was selected as an eco-efficient solvent from over 100 organics, resulting in the reduction of TAC by 7.8% and CO2 emission by 16.9% in the production process. Also, acetophenone led to the increase of cyclohexanol yield from 12.3% to 27.6% without the occurrence of side reactions or catalyst deactivation.

Droplet breakup in micro-constrictions is an important phenomenon in industrial applications. This work aimed to investigate the droplet breakup in the square microchannel with a short square constriction to generate the slug flow, which drew little attention before. Mechanism analysis indicated that this breakup process included the shear-force-dominated, squeezing-force-dominated, and pinch-off stages. Non-uniform daughter droplets were generated in the constriction with their interface restricted in the horizontal and perpendicular directions by the microchannel walls. The average relative deviation of the daughter droplet size was < 30%, much lower than that for the breakup with the daughter droplet restricted only in one direction. An empirical equation with a deviation of < 20% was provided to show the dependence of the daughter droplet size on the operation conditions. The comparison results suggested that the different restriction effects of microchannel wall on daughter droplets led to the different breakup mechanisms in different constrictions.