Cross-polymerisation between furfural and the phenolics of varied molecular structure in bio-oil

Abstract The high tendency bio-oil towards polymerisation on heating makes bio-oil a potential feedstock for production of carbon materials. In this study, the cross-polymerisation of the typical furans and aromatic compounds in bio-oil was conducted to understand the impacts of structures of the aromatic compounds on their tendencies towards polymerisation. The results showed that the cross-polymerisation between furfural and the phenolics did exist. The reactivity of the aromatic compounds towards cross-polymerisation with furfural depended on the electron density of their benzene ring. Guaiacol and eugenol with the electron-donating functionalities were very reactive towards polymerisation, while toluene was not that reactive. The relatively electron-deficient benzene ring made benzoic acid almost inert in the polymerisation. Acetic acid showed insignificant effects on promoting the polymerisation, due to the weak acidity, while H2SO4 could remarkably promote the cross-polymerisation. Besides, the hydrophilicity/hydrophobicity of substituents on benzene rings affected the morphology and structure of polymers.