New green route to obtain (bio)-propene through 1,2-propanediol deoxydehydration

Deoxydehydration (DODH) reaction on 1,2-pmpanediol (1,2-PD) catalyzed by rhenium, conducted in 2,4-dimethyl-3-pentanol (DMP) or in neat 1,2-PD, was carried out. The experimental apparatus was planned to recover separately all the reaction products: in one reaction vessel, the gaseous propene was collected while all the other reaction products, above all regarding the transformation of 1,2-PD, were collected in another reaction vessel. The most common commercial high oxidation state rhenium compounds, methytrioxorhenium (MTO), ReO3, Re2O7 and NH4ReO4, were selected as catalysts. Among them, MTO and Re2O7 gave the best performance in terms of propene production even if ReO3 showed a moderate yield of another reaction product, the acetal formed by coupling of 1,2-PD and 1-hydroxypropanone, that can be considered an innovative strategy to make value over the 50% of the diol.