Novel process for the extraction of ethyl levulinate by toluene with less humins from the ethanolysis products of carbohydrates

A series of organic solvents were screened for the extraction of ethyl levulinate (EL) from the concentrated ethanolysis products of sucrose. Among these organic solvents, toluene was confirmed as an outstanding extracting agent for separating EL with less humins from the concentrated reaction products. The EL extraction rate was strongly related to the temperature and duration applied in the vacuum concentration; a maximum EL recovery of 96.7% can be achieved through the extraction by toluene from the ethanolysis products. Herein, the catalytic transfer hydrogenation (CTH) of biomass-derived EL to γ-valerolactone (GVL) was also performed over inexpensive metal oxides using ethanol as a hydrogen donor. On the basis of these scenarios, a novel process for the production and separation of EL and GVL from carbohydrates was proposed to integrate the ethanolysis of carbohydrates and the CTH of EL.