Selective dissolution of hemicellulose from Phyllostachys heterocycla cv. var. pubescens (shortened to pubescens afterwards), and conversion of dissolved hemicellulose into value-added monomers (such as furfural and levulinic acid) promoted by AlCl3 under solvent-thermal conditions were investigated. Solid biomass samples were characterized by chemical titration and XRD techniques. Liquid products were analyzed by GC-FID, HPLC, and GPC. In the AlCl3 promoted dissociation of hemicellulose from pubescens, the conversion of hemicellulose reached 72.6 wt% without significant degradation of cellulose and lignin (only 10.4 wt% and 13.3 wt%, respectively) after hydrothermal treatment at a rather low temperature of 120 °C for 4 h. The extracted hemicellulose could be divided mainly into two parts, that is, monomers (such as xylose, furfural and acetic acid, about 36.1%) and oligomers (about 63.9%). THF and SiO2 were added, forming a SiO2–AlCl3–H2O/THF system, for the further conversion of the oligomers and monomers derived from hemicellulose. The selectivity towards total monomers could reach 97.6% based on the converted pubescens. High selectivity towards value-added monomers (39.1% furfural and 48.3% levulinic acid) was obtained at 160 °C.

SO42−–MoO3–ZrO2–Nd2O3/SiO2 (SMZN/SiO2) catalysts for the production of biodiesel via both esterification and transesterification were prepared and characterized by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA), ammonia adsorption Fourier transform infrared spectra (NH3-FTIR), and ammonia adsorption temperature programmed desorption (NH3-TPD) to reveal the dependence of the stable catalytic activity on calcination time. The reason for catalyst deactivation was also studied. The calcination time remarkably affected the types of active centers on SMZN/SiO2, and 4 h was found to be the optimal calcination time. SO42− species bonded with small size ZrO2 were found to be the stable active centers, where the leaching of SO42− and the deposition of coke were inhibited. The deposition of coke was easier on large size ZrO2 than on small size ones. Calcination in air flow could eliminate the deposited coke to recover the deactivated catalysts.SO42- species bonded with small size ZrO2 were found to be the stable active centers, where the leaching of SO42- and the deposition of coke were inhibited.Download high-res image (245KB)Download full-size image