催化学报 ›› 2018, Vol. 39 ›› Issue (10): 1711-1723.DOI: 10.1016/S1872-2067(18)63110-9

• 论文 • 上一篇    

Cu-LaCoO3催化剂选择氢解生物质基糠醇制备1,5-和1,2-戊二醇

高芳芳a,b, 刘海龙a, 胡勋a, 陈静a, 黄志威a, 夏春谷a   

  1. a 中国科学院兰州化学物理研究所, 羰基合成与选择氧化国家重点实验室, 苏州研究院, 甘肃兰州 730000;
    b 中国科学院大学, 北京 100049
  • 收稿日期:2018-04-07 修回日期:2018-05-25 出版日期:2018-10-18 发布日期:2018-08-03
  • 通讯作者: 陈静, 黄志威
  • 基金资助:

    国家自然科学基金(21473224);中科院前沿科学重点研究项目(QYZDJ-SSW-SLH051);中科院青年创新促进会(2016371);苏州科技发展计划(SYG201626).

Selective hydrogenolysis of furfuryl alcohol to 1,5-and 1,2-pentanediol over Cu-LaCoO3 catalysts with balanced Cu0-CoO sites

Fangfang Gaoa,b, Hailong Liua, Xun Hua, Jing Chena, Zhiwei Huanga, Chungu Xiaa   

  1. a State Key Laboratory for Oxo Synthesis and Selective Oxidation, Suzhou Research Institute of LICP, Lanzhou Institute of Chemical Physics(LICP), Chinese Academy of Sciences, Lanzhou 730000, Gansu, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-04-07 Revised:2018-05-25 Online:2018-10-18 Published:2018-08-03
  • Contact: 10.1016/S1872-2067(18)63110-9
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21473224), Key Research Project of Frontier Science of Chinese Academy of Sciences (QYZDJ-SSW-SLH051), the Youth Innovation Promotion Association, CAS (2016371), and the Suzhou Science and Technology Development Plan (SYG201626).

摘要:

高效转化可再生生物质资源制备人类社会必需的燃料和化学品是当前关注和研究的热点之一.生物质基糠醇来源于玉米芯、甘蔗渣、秸秆等农林副产物,价廉易得,是选择氢解合成高附加值1,2-和1,5-戊二醇的理想原料.目前生物质基呋喃衍生物氢解制备二元醇的研究主要集中在Pt,Ru,Rh和Ir等贵金属催化剂,对无Cr非贵金属催化剂的研究甚少.基于纳米Cu催化剂较高的C-O键氢解活性和较低的C-C键裂解活性,以及碱性载体对反应物和反应中间体的稳定作用,我们在前期Cu-Mg3AlO4.5和Cu-Al2O3催化剂催化糠醇氢解研究基础上,以具有一定碱性的ABO3结构的钙钛矿型化合物为载体负载活性Cu开展糠醇氢解研究,深入研究催化剂结构、组成和活性金属价态等对催化剂活性和选择性影响,并研究了催化剂循环使用稳定性.
首先我们采用柠檬酸一步络合法制备了一系列具有一定钙钛矿结构的不同Cu负载量(0-20 wt%)的Cu-LaCoO3催化剂以及LaCoO3负载的5 wt% Pt,Ru,Rh和Pd催化剂并考察了它们的糠醇选择氢解制备戊二醇性能.研究发现,在相同活性金属负载量(5 wt%)时,Cu-LaCoO3催化剂具有较优异的呋喃环C-O键氢解活性,而贵金属催化剂倾向于催化呋喃环C=C键加氢饱和.考察不同Cu负载量的Cu-LaCoO3催化剂催化糠醇氢解性能发现,随着Cu负载量的增加,糠醇转化率先升高后降低,在10 wt% Cu负载量时达最高(94.6%),戊二醇总选择性也随Cu负载量的增加先升高后降低,在5 wt% Cu负载量时最高(52.2%),总体以10 wt% Cu负载量催化剂表现出最优异的性能.
接着我们考察了反应动力学条件如温度、压力和反应时间以及还原处理条件对10 wt% Cu-LaCoO3催化性能的影响.研究发现适当的高温(~433 K)和高压(6 MPa H2)有利于Cu-LaCoO3催化糠醇氢解制戊二醇,而低浓度氢气(5 vol%)还原有利于1,5-戊二醇的生成,高氢气浓度(纯氢)还原有利于呋喃环加氢饱和的四氢糠醇生成.10 wt% Cu负载量的催化剂经5% H2-95% N2处理后,在413K和6MPa H2条件下可取得100%的糠醇转化率以及55.5%的戊二醇总选择性(其中1,5-戊二醇和1,2-戊二醇的选择性之比接近3:1).进一步考察了10 wt% Cu-LaCoO3催化剂的循环使用稳定性,研究发现无论是在高初始转化率(~93.7%)还是低初始转化率(~30.5%)条件下,经多次循环使用后糠醇转化率先升高后基本保持不变,而戊二醇总选择性呈下降趋势,四氢糠醇的选择性逐渐上升.
结合XRD,XPS,BET,H2-TPR,CO2-TPD,NH3-TPD和HRTEM等多种表征技术对Cu-LaCoO3催化剂的结构及在糠醇氢解反应中的活性位进行了表征,发现高分散的活性物种、合适的碱性以及部分还原的活性组分均有利于提高催化剂的活性与1,5-戊二醇的化学选择性,高分散的Cu0与部分还原的Co3O4(很可能是CoO)之间的协同催化对于取得较优异的糠醇氢解性能,尤其是较高的1,5-/1,2-戊二醇比例至关重要.

关键词: 糠醇, 选择性氢解, 戊二醇, 铜-钴酸镧催化剂, 钙钛矿结构

Abstract:

Selective hydrogenolysis of biomass-derived furfuryl alcohol (FFA) to 1,5-and 1,2-pentanediol (PeD) was conducted over Cu-LaCoO3 catalysts with different Cu loadings; the catalysts were derived from perovskite structures prepared by a one-step citrate complexing method. The catalytic performances of the Cu-LaCoO3 catalysts were found to depend on the Cu loading and pretreatment conditions. The catalyst with 10 wt% Cu loading exhibited the best catalytic performance after prereduction in 5% H2-95% N2, achieving a high FFA conversion of 100% and selectivity of 55.5% for 1,5-pentanediol (40.3%) and 1,2-pentanediol (15.2%) at 413 K and 6 MPa H2. This catalyst could be reused four times without a loss of FFA conversion but it resulted in a slight decrease in pentanediol selectivity. Correlation between the structural changes in the catalysts at different states and the simultaneous variation in the catalytic performance revealed that cooperative catalysis between Cu0 and CoO promoted the hydrogenolysis of FFA to PeDs, especially to 1,5-PeD, while Co0 promoted the hydrogenation of FFA to tetrahydrofurfuryl alcohol (THFA). Therefore, it is suggested that a synergetic effect between balanced Cu0 and CoO sites plays a critical role in achieving a high yield of PeDs with a high 1,5-/1,2-pentanediol selectivity ratio during FFA hydrogenolysis.

Key words: Furfuryl alcohol, Selective hydrogenolysis, Pentanediol, Cu-LaCoO3 catalyst, Perovskite structure