Reaction process for ZnCl₂activation of phenol liquefied wood fibers

In this study, ZnCl2 activation of phenol liquefied wood fibers at different temperatures was conducted to investigate the reaction mechanisms during the activation process. By combining Fourier transform infrared (FTIR) spectroscopy, thermogravimetric-FTIR-mass spectrometry (TG-FTIR-MS) and elemental analysis, the reaction mechanisms during the ZnCl2 activation were deduced. Below 327 °C, dehydration of the hydroxyl groups and fracturing of molecular chains occurred inside the fiber. At 327–700 °C was the main stage of activation, where molecular structure was rearranged due to intramolecular condensation, crosslinking reactions and scission of molecular chains. A carbon net-like structure was preliminarily formed at 402 °C. Due to the removal of pyrolysis products such as H2, H2O, CO, CO2, benzene and phenol, surface defects were filled in molten ZnCl2. Pores would be left on the fiber surface after activation, cooling and cleaning. Above 700 °C, the aromatization degree and the degree of aromatic ring gradually improved.