Mechanistic investigation of CO generation by pyrolysis of furan and its main derivatives

A large amount of furan and its derivatives are contained in the biomass pyrolysis products, which mainly lead to the formation of combustible CO with an increase in the pyrolysis temperature; in this study, to illuminate the reaction mechanisms involved in the evolution of CO during the pyrolysis of furan and its main derivatives, quantum chemical theory has been adopted with the GGA-RPBE method, and nine possible reaction pathways have been investigated for the pyrolysis of furan, furfural (FF), furfuryl alcohol (FA) and 5-hydroxymethylfurfural (5-HMF) to generate CO. According to the calculation results, the optimal path for the pyrolysis of furan and its main derivatives to generate CO is as follows: at first, a ring opening reaction of furan occurs to form an aldehyde group, and then, decarbonylation occurs to form CO. Furthermore, the side chain functional groups on the furan ring can promote the ring opening reaction of the furan ring. In addition, the reaction energy barriers of the rate-determining step for the pyrolysis of furan, furfural, furfuryl alcohol and 5-hydroxymethylfurfural (5-HMF) to form CO have been determined as 343 kJ mol(−1), 330 kJ mol(−1), 317 kJ mol(−1) and 363 kJ mol(−1), respectively.