Energy issues in the utilization of CO₂ in the synthesis of chemicals: The case of the direct carboxylation of alcohols to dialkyl-carbonates

This paper aims at highlighting the hurdles and traps on the way back from CO₂ to chemicals (or even fuels). The case of the synthesis of dialkyl carbonates is discussed, considering several synthetic conditions and comparing the relevant amount of energy necessary for product separation. The calculations show that the post-reaction separation process may share an important part of the energy consumption in the whole synthetic procedure and make, in some conditions, the reaction a strong CO₂ emitter more than a CO₂ consumer.