物理化学学报 >> 2012, Vol. 28 >> Issue (10): 2343-2348.doi: 10.3866/PKU.WHXB201206152

催化和表面科学 上一篇    下一篇

贵金属催化剂上两步法选择性降解有机溶剂型木质素

刘凌涛, 张斌, 李晶, 马丁, 寇元   

  1. 北京大学化学与分子工程学院, 北京大学绿色化学研究中心, 北京分子科学国家实验室, 北京 100871
  • 收稿日期:2012-05-08 修回日期:2012-06-15 发布日期:2012-09-26
  • 通讯作者: 寇元 E-mail:yuankou@pku.edu.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2011CB201402)资助

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).

摘要:

使用担载型贵金属催化剂和磷酸在不同温度下通过两步法加氢降解二氧六环木质素. 第一步反应使用Rh/C和浓度为1% (w)的磷酸为催化剂, 在270 ℃和4 MPa氢气气氛下反应后通过气相色谱(GC)和气相色谱-质谱(GC-MS)分析木质素单体和二聚体, 总收率最高可达16.9%. 通过傅里叶变换红外(FTIR)光谱、X射线光电子能谱(XPS)、元素分析(EA)和凝胶渗透色谱(GPC)等方法研究第一步反应产物的变化. 结果发现, 二氧六环木质素中的C-O-C键被打断, 木质素分子量降低, 部分羰基和羧基被脱除. 随着反应温度的上升, 产物的含氧量不断下降, 在270 ℃反应10 h 后氧含量从35% (w)降低至21% (w). 结合不同的表征方法, 提出二氧六环木质素的第一步反应路径. 第二步反应中使用Pd/C和磷酸为催化剂在250 ℃可以将木质素单体、二聚体高选择性地加氢脱氧转化为对应的烃类产物.

关键词: 二氧六环木质素, 降解, 氢解, 加氢脱氧, 液体燃料

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