Diethyl Carbonate Production from CO2 and Ethanol in an Isothermal Pfr via Aspen Plus Simulation

Abstract

In this work, diethyl carbonate (DEC) production from CO₂ and ethanol, coming from the bioethanol plant, is studied using 2-cyanopyridine (2-CP) as a dehydrating agent and CeO₂ as a catalyst. Aiming to integrate existing plants and applying the concept of circular economy, this work has the appeal of not emitting carbon dioxide and valuing renewable carbon in the production of diethyl carbonate, a compound with high added value that can be applied as lithium battery electrolyte and as an intermediate in obtaining ketones, tertiary alcohols, and heterocyclic components. The DEC production proposed in this work was simulated via Aspen Plus V10 software. The reaction system is composed of the following reagents: carbon dioxide (CO₂), ethanol (EtOH), diethyl carbonate (DEC), water (H₂O), 2-cyanopyridine (2-CP), picolinamide (2-PA), ethyl picolinimidate (EPI), ethyl picolinate (EP), ammonia (NH₃), and ethyl carbamate (EC). The mixture properties were calculated using the Non-Random-Two-Liquid (NRTL) method. The reaction mixture composition used was 10 kmol/h of ethanol, 15 kmol/h of CO₂, and 5 kmol/h of 2-CP. The reactor was simulated as a multi-tubular isothermal plug flow reactor (PFR). The kinetic reactions were modeled using power law equations. The effect of reactor operating temperature (range 130–150 °C) and reactor dimensions on ethanol conversion was studied. At 50 atm and 130 °C, 4.01 kmol/h of DEC was obtained at the output stream of the reactor, corresponding to 11.37 t/day with an ethanol conversion of 82.85 %. From the open literature, this is the first work that the DEC production from ethanol and CO₂ is simulated in a multi-tubular reactor.