碳化钼催化材料的制备及其反应性能研究

发布时间：2018-04-12 00:36

本文选题：柠檬醛加氢 + 碳化钼　；参考：《华东理工大学》2017年硕士论文

【摘要】：α,β-不饱和醛/酮及其加氢产物为农化、医药、精细化工、食品工业等领域提供了丰富的化工原料及中间体。近年来,对于该类有机物合成的探索日益增多,现有研究主要集中在贵金属催化剂,较高的商业成本和性能的不理想是此类催化剂在该反应中实现工业化的瓶颈。碳化钼作为催化材料具有与铂、钯等贵金属相近的催化加氢效能,而被誉为"类铂催化剂",利用过渡金属碳化物对贵金属催化剂作为替代是一个解决贵金属资源紧张和降低使用成本的有效途径,有利于丰富碳化钼种类完善制备理论和工艺,对该类催化材料应用范围的拓宽具备实践意义。本论文工作以钼酸铵和有机胺(苯胺、十二胺、乙二胺、吡啶和四乙烯五胺等)为原料,通过有机-无机杂化法利用共沉淀首先得到特定形貌(纳米线、层状、长方体及片层堆积)的M_oO_x/amine前躯体,再采用程序升温反应法在氮气中高温热解前躯体进行渗碳反应,制备出多种碳化钼催化剂。尝试以1,6-己二胺、1,2-丙二胺为客体在前躯体合成时加入氧化剂APS,得到了形貌了枝状前躯体和暴露(101)晶面的介孔M_oC材料。同时,引入CTAB、SDS、PEG-1500等考察表面活性剂对所合成前躯体形貌的影响,探索其影响机制及规律。采用SEM、TEM、XRD、TGA等表征手段对样品进行物性分析,比较不同制备过程对样品造成的性质差异,总结调控规律。以非贵金属催化剂柠檬醛选择性加氢制备橙花醇/香叶醇的反应,对碳化钼样品的选择性加氢效能能进行考察,提出将碳化钼作为精细化工中选择性加氢反应催化剂的新思路。研究结果表明:在水溶液中通过改变杂化前躯体中有机胺的种类可得到形貌和晶面可调的体相碳化钼,并达到增大比表面积的效果。杂化过程中引入表面活性剂对晶粒形貌和分散性都有不同程度的改善。采用有机-无机杂化法制备的体相碳化钼对柠檬醛催化加氢的转化率可达88%,选择性受暴露晶面的不同而体现较大差异性。
[Abstract]:伪, 尾 -unsaturated aldehydes / ketones and their hydrogenation products provide abundant chemical raw materials and intermediates for agrochemical, pharmaceutical, fine chemical, food industry and so on.In recent years, more and more researches have been made on the synthesis of this kind of organic compounds. The existing researches mainly focus on noble metal catalysts. The high commercial cost and unsatisfactory performance are the bottleneck of industrialization of this kind of catalysts.Molybdenum carbide as a catalytic material has similar catalytic hydrogenation performance to platinum, palladium and other precious metals.The transition metal carbide is an effective way to solve the shortage of precious metal resources and reduce the cost of use. It is beneficial to enrich the preparation theory and technology of molybdenum carbide.It is of practical significance to widen the scope of application of this kind of catalytic materials.In this paper, ammonium molybdate and organic amines (aniline, dodecylamine, ethylenediamine, pyridine and tetraethylenepentylamine) were used as raw materials.The M_oO_x/amine precursor of cuboid and lamellar) was prepared by using programmed temperature reaction method to carburize the precursor body at high temperature in nitrogen to prepare various molybdenum carbide catalysts.A mesoporous M_oC material with dendritic precursor and exposed crystal plane was obtained by adding oxidizer APSs in the synthesis of prosomas by using 1Hexanediamine as the guest.At the same time, the influence of surfactant on the morphology of the precursor was investigated by introducing CTABX SDS- PEG-1500, and the mechanism and regularity of the influence were explored.The physical properties of the samples were analyzed by means of SEMTEMX XRDGA, and the properties of different preparation processes were compared, and the regulation rules were summarized.Selective hydrogenation of citral to hesperol / geraniol was carried out on a non-noble metal catalyst. The performance of selective hydrogenation of molybdenum carbide samples was investigated. A new idea of using molybdenum carbide as a catalyst for selective hydrogenation in fine chemical industry was put forward.The results show that molybdenum carbide with adjustable morphology and crystal plane can be obtained by changing the kinds of organic amines in the hybrid body in aqueous solution, and the effect of increasing the specific surface area can be achieved.The addition of surfactants in the hybrid process improves the grain morphology and dispersity in varying degrees.The conversion of molybdenum carbide prepared by organic-inorganic hybrid method for catalytic hydrogenation of citral can reach 88%.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

【参考文献】