Liquefaction of Chinese fir bark in the presence of phenol
To assess the feasibility of using Cunninghamia lanceolata (Chinese fir) bark as a raw material for the formulation of phenol based adhesives, the liquefaction technique for Chinese fir bark was studied using phenol as the liquefacient. The effects of reaction temperature, liquid ratio (phenol/Chinese fir bark), reaction time, as well as kinds and usage of catalysts [hydrochloric acid (HCl), phosphoric acid (H3PO4), and sulfuric acid (H2SO4)] on liquefaction were investigated. Also, Fourier transform infrared spectroscopy (FTIR) was used to characterize the structure of Chinese fir bark and its liquefaction products. Results showed that, compared to HCI and H3PO4, H2SO4 had an excellent catalytic effect on the liquefaction of Chinese fir bark, and that a lower residue yield was obtained. Optimum liquefaction conditions were: liquefaction time 1.0 h, liquefaction temperature 150 ℃, liquid ratio 3/1, H2,SO4 as a catalyst 72%(720 g·kg-1), and catalyst dosage 0. 15 mL·g-1. With these conditions, the liquefaction residue rate was 9.97%. This indicated that the chemical components of Chinese fir bark were subjected to phenolization reactions. With additional studies of resole formation and glue mix formulations, it is anticipated that a resin adhesive from liquefied Chinese fir bark with improved bond quality can be developed.