Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (10): 2343-2348.doi: 10.3866/PKU.WHXB201206152

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Selective Degradation of Organosolv Lignin over Noble Metal Catalyst in a Two-Step Process

LIU Ling-Tao, ZHANG Bin, LI Jing, MA Ding, KOU Yuan   

  1. PKU Green Chemistry Center, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
  • Received:2012-05-08 Revised:2012-06-15 Published:2012-09-26
  • Contact: KOU Yuan E-mail:yuankou@pku.edu.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2011CB201402).

Abstract:

Dioxane lignin, a typical organosolv lignin, was degraded by supported noble metal catalysts and phosphoric acid by a two-step method at different temperatures. The results showed that under 4 MPa H2 at 270 ℃ using Rh/C and 1% (w) phosphoric acid as catalysts, the highest total yield of the monomers and dimer was 16.9% after the first step, based on gas chromatography (GC) and gas chromatographymass spectrometry (GC-MS) analyses. Moreover, the raw products from the first step were analyzed by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), element analysis (EA), and gel permeation chromatography (GPC) to improve the understanding of the chemical transformations involved. The results indicated that the C-O-C bond linkages in the dioxane lignin were cleaved to form lower molecular-weight products, resulting in the degradation of lignin, and the carbonyl and carboxyl groups were partly removed. Oxygen content was reduced dramatically with increasing reaction temperature, from 35% (w) to 21% (w) after reacting at 270 ℃ for 10 h. Based on the analysis results, a reaction pathway for the degradation of lignin was proposed. Finally, the products from the first step could be hydrodeoxygenated to alkanes with carbon numbers in the range of gasoline and diesel with high selectivity catalyzed by Pd/C and phosphoric acid at 250 ℃.

Key words: Dioxane lignin, Degradation, Hydrogenolysis, Hydrodeoxygenation, Liquid fuel

MSC2000: 

  • O643