高分散含氮功能材料的制备及用于催化生物质衍生物构建碳-杂键高值转化

This work aims to upgrade biomass derivatives via the catalytic creation of carbon-hetero bonds over rationally designed base-metal functional materials. First, substituted phenylcarboxylic acids and phosphonic acids are selected as organic ligands, imidazole, benzimidazole and relevant derivatives as nitrogen sources, followed by solvothermal or room-temperature self-assembly treatment and calcination processes to synthesize highly dispersed nitrogen-containing base-metal functional carbonaceous materials. The effects of temperature, solvent type, metal/nitrogen type and dosage on the pore distribution, specific surface area and type of chemical functional groups on the materials are also investigated. Secondly, the production of biodiesel from plant oils is selected as model reaction for the establishment of C-O bond, and the optimized base-metal bifunctional magnetic nanocatalysts are used to catalyze reductive amination of lignocellulose-derived aldehydes and ketones (containing carbohydrates and hydrolysates) being converted to corresponding value-added organic amines (C-N bond formation); the influence of nitrogen source, different catalysts and metal sites on the capability of anti-carbon deposition and the role of metal-nitrogen bonding mode in the activity of catalytic creation of carbon-hetero bonds are investigated; Moreover, isotopic labeling and in-situ characterization methods are conducted to study the catalytic mechanism for the reductive amination of specific substrates. Thirdly, a self-designed reactor is utilized to produce value-added compounds such as amines and biodiesel over optimal catalysts via the formation of carbon-hetero bonds, in the aim of achieving the easy separation and recycle of the magnetic catalysts after reactions. Based on the above investigations, it is highly desirable to develop green processes (without producing any wastes) and efficient catalytic systems for the synthesis of biomass-derived valuable products (e.g., amines) via the establishment of carbon-hetero bonds.

本项目目的是设计制备碱-金属功能材料，催化构建碳-杂键高值转化生物质。首先，选取多取代苯甲酸、膦酸或生物质基有机酸等为有机配体，咪唑、苯并咪唑等衍生物为有机氮源，经热液或室温自组装、煅烧合成出高分散含氮碳基碱-金属功能材料；探讨温度、溶剂类型、金属/氮源种类和用量等对其空隙分布、比表面积及化学官能团类型的影响。其次，以油脂合成生物柴油为模型反应构建C-O键，将修饰改进制备出碱-金属双功能磁性纳米材料用于催化木质纤维素衍生物（如醛或酮）还原氨化制备出有机胺化物(C-N键形成)；考察不同氮源、催化剂及金属位点抗积碳的影响，和金属/氮键联模式对催化构建碳-杂键活性的作用；运用同位素标记和原位表征等手段开展氨化催化机制研究。最后，在磁性分离反应釜中，生产含碳-杂键的高附加值化合物以实现催化剂磁性分离和循环。研发出从木质纤维素主要组分通过构建碳-杂键，制备高附加值产品的高效催化体系和绿色工艺流程。

催化碳水化合物及其衍生物转化为高附加值化学品被认为能极大提高非食用生物质资源的利用率，并具有替代石化产品满足化工生产原料供给的潜能。本项目以构筑双功能催化剂选择性转换生物质衍生物形成C-N、C-O键为目标，研究了不同种类生物质衍生物的转换反应，主要结果如下：1、以氧化钙/生物炭为催化剂，采用催化快速热解法对大豆油进行催化脱氧，实现了酚醛树脂制备酚醛油和植物油制备富芳烃油；2、以γ-Al2O3-2%H3PO4为双功能催化剂，将聚对苯二甲酸乙二醇酯塑料直接转化为对苯二甲腈(TPN)等含氮化合物。腈类化合物和TPN的收率分别为58.1%和52.3%，TPN在腈类中的选择性约为90%；3、通过NaOH碱化废白土灰制备双功能催化剂，直接催化大豆油制备生物柴油产率为99.2%，重复使用3次后产率为87%，催化酸值5.9 mg KOH/g的油脂得生物柴油产率为91.9%，且未见皂化；4、制备La2O2CO3-Al2O3双功能催化剂，具有更多的La3+-O2-碱性位点，在羟醛缩合反应中表现出良好性能。糠醛/丙酮比为1/1和90 ℃时，糠醛总转化率为67.8%， FAc产率为25.8%；5、以HZSM-5-3(Si/Al=80)为催化剂在650 ℃高温下裂解酚醛树脂，得到14.2C%的芳香胺，且产物中芳香胺的选择性达到57.6%。当木质素与酚醛树脂1:1混合时，芳香胺产率提高32.2%；6、制备了Co-Zr/CNx纳米粒子，在130 ℃水中能有效地将生物基乙酰丙酸直接转化为5-甲基-2-吡咯烷酮，在还原胺化过程中发现双金属催化剂长时间具有高活性。综上所述，本项目研究了生物质衍生物的选择性转化为含氮化合物，利用新催化剂催化构建碳-杂键合成生物质基有机胺的绿色工艺。详细研究了双功能催化剂的作用机理，获得多种高效反应的方法和途径。本项目研发出高效制备生物质基高附加值有机胺的绿色工艺流程以及催化体系。