The cycloaddition of CO2 and ECH can be performed without solvents . Ionic metalloporphyrin encapsulated ZIF-8 offered a solvent-free synthesis of cyclic carbonates from CO2 (1 atm) and epoxides without co-catalyst . The presence of dehydrating agents is vital for the reaction that produces water . MgCO3 and CH3CN are the common dehydrating agents. The activation energy of using MgCO3 (5.4 kJ/mol) is lower than that of using CH3CN (7.8 kJ/mol) . The electrolytes for the electrochemical method are essential. NaCl showed the highest electrochemical reduction of CO2 to the CO selectivity .