Phosphotungstic acid catalysed bioethylene synthesis under industrially relevant conditions

Abstract

Among the different routes of ethylene production, the most plausible way to obtain it from renewable sources nowadays is the dehydration of bioethanol, which can be obtained from biomass or municipal waste. The dehydration of ethanol to ethylene over heteropoly acid catalysts can be advantageous in comparison to other acid catalysts such as zeolites or γ-Al₂O₃ due to the lower temperature at which the former ones work. This paper studies a trilobe-shaped phosphotungstic acid-based catalyst synthesized by impregnation to be used in the dehydration of ethanol. The catalyst has shown outstanding activity, reaching equilibrium conversion of ethanol under different reaction conditions. In order to assess the catalyst potential for industrial application, relevant conditions were considered, such as the absence of N₂ in the feed or the performance of the material at long times of reaction (>250 h). The selectivity towards ethylene was maximized by the optimization of the conditions, and the catalyst has shown good activity for bio-ethylene production (equilibrium ethanol conversion and selectivity towards ethylene >90%) different from a real 1st generation bioethanol.