纤维素一步转化为DMF和烷烃液体燃料的固体组合催化剂与产物调控规律

This project focuses on preparation of efficient solid combined catalyst and relative mechanism and production controlling mechanism in one-pot transformation of cellulose to value-added liquid biofuel including oxygen contained 2,5-dimethyl furan (DMF) and C5/C6 alkanes. This project constructs water and organic contained bi-phase reaction system and new pathway based on 5-hydroxymethyl furan (HMF) intermediate formation and sequential transformation. In detail, this project implements the investigation on controllable preparation of hydrophilic and acidic solid metal phosphates and sheds light on the goal production formation and byproduct suppression mechanism of cellulose depolymerization to glucose, glucose isomerization to fructose and fructose dehydration to HMF in water by the synergistic effect of Bronsted and Lewis acidic sites over catalyst. On the other hand, this project, based on selective conversion of HMF into DMF in organic phase, is also carried out by the preparation of hydrophobic bi-functional catalyst involved metal and acid, and investigates partial hydrogenation and hydrodeoxygenation (HDO) of HMF to DMF, which involves the steps of hydrogenation of carbonyl group and HDO of the two hydroxyl groups in HMF molecule. Moreover, by adjusting the properties of bi-functional catalyst by choosing support, metal and acid component, complete HDO of HMF to C5/C6 alkanes will be also implemented by furan saturation, ring opening and HDO steps. By these investigation, the preparation methodologies of hydrophilic solid acid catalyst and hydrophobic, bi-functional metal-acid catalyst will be obtained, and the mechanisms of coupling reaction and diffusion-reaction will be mastered in one-pot conversion of cellulose to DMF and C5/C6 alkanes in water-organic bi-phase system. This project will give potential solution for poor activity and selectivity of ordinary, previous reported catalysts used in this transformation, and new idea for highly efficient utilization of cellulosic biomass.

本项目围绕纤维素一步转化为高值2,5-二甲基呋喃（DMF）和C5/C6烷烃液体燃料中高效固体组合催化剂制备和纤维素解聚与转化反应机理、产物控制规律的研究目标，构筑水-有机双相反应体系和基于5-羟甲基糠醛（HMF）中间产物转化的新路径，研究亲水性金属磷酸盐固体酸和疏水性金属-酸双功能催化剂的可控制备与性能调控规律，阐明纤维素水相解聚制备HMF过程中固体酸B酸/L酸协同催化的β-1,4糖苷键断裂、葡萄糖异构和果糖环化脱氧的反应机理和副产物抑制规律，揭示HMF有机相定向转化为DMF和C5/C6烷烃中金属-酸界面协同加氢脱氧的转化路径和产物调控机制，明晰过程强化条件下纤维素一步转化为上述液体燃料的耦合反应机理与传递-反应的协同作用机制。通过项目研究，解决纤维素解聚和选择性转化过程效率低和产物可调性差的关键问题，为纤维素生物质的高效高值化利用提供新思路。

本项目围绕生物质基纤维素制备C5/C6烷烃和生物乙醇，碳水化合物制备DMF以及碳氢化合物中催化剂的制备及氢解路线研究，生物质的主要成分纤维素经水解后，主要的产物为C5、C6多羟基化合物，来源广泛，价格低廉，而液体燃料如生物乙醇以及C5/C6烷烃具有很高的应用价值和市场需求。与此同时，研究纤维素水解后的碳水化合物向碳氢化合物的转化有助于认识复杂纤维素转化中的反应机理及路径，为进一步提高纤维素的利用效率和产物的选择性转化提供了较高的参考价值。.1.1纤维素制备C5/C6烷烃。此工作构建了金属/载体-分子筛催化体系，催化纤维素一步氢解加氢制备C5/C6烷烃。主要研究了微晶纤维素和在金属/载体-分子筛催化作用下制备C5/C6烷烃，发现不同的金属配比显著影响反应效果，对催化剂的制备以及反应工艺条件进行了优化，分析了反应路径，并对制备的催化剂进行了表征。提出了催化剂Ir-MoOx/SiO2耦合分子筛HZSM-5作用下纤维素解聚加氢的途径。为纤维素转化制备C5/C6烷烃的可能转化路径提供了更加清楚的认知。.1.2生物质基果糖和HMF向DMF的转化。此工作构筑水-有机双相反应体系和基于5-羟甲基糠醛（HMF）中间产物转化的新路径，研究亲水性金属磷酸盐固体酸和疏水性金属-酸双功能催化剂的可控制备与性能调控规律，阐明纤维素水相解聚制备HMF过程中固体酸B酸/L酸协同催化的β-1,4糖苷键断裂、葡萄糖异构和果糖环化脱氧的反应机理和副产物抑制规律，揭示果糖和HMF有机相定向转化为DMF中金属-酸界面协同加氢脱氧的转化路径和产物调控机制，明晰过程强化条件下纤维素一步转化为上述液体燃料DMF的耦合反应机理与传递-反应的协同作用机制。.1.3纤维素选择性氢解制备生物乙醇。制备具有高耐热、酸性的石墨烯层封装的包裹催化剂Ni@C耦合H3PO4直接一步法水解、选择性氢解制备生物乙醇，收获了与葡萄糖发酵理论值相当的69.1%的乙醇收率。此工作提出了不同于其他生物乙醇生成的反应路径，为可再生纤维素的高效利用提供了另外一种可能性。.1.4生物质衍生化合物制备碳氢化合物。通过研究模型化合物的水热降解行为并分析了这些化合物的降解途径，我们证明了α-羰基醛和α-羰基酸是碳水化合物水热降解过程中形成固体腐殖质的关键主要前体。通过进一步研究α-羰基醛和α-羰基酸的催化转化将有助于从碳水化合物中获得有价值的化学物质。