【作者】 郁茵茵；

【导师】 侯震山；

【作者基本信息】 华东理工大学 ， 工业催化， 2013， 博士

【摘要】 加氢反应是很多基本的化学结构单元进行官能化的基础,加氢反应能单纯增加有机化合物中氢原子的数目,使不饱和的有机物转变为相对饱和的有机物,这在现代化学工业中是重要的领域之一。因此,开发清洁有效的绿色加氢催化体系具有深远的研究意义。本课题主要内容是从绿色化学的角度出发,选取绿色反应溶剂和催化剂,使用不同的氢源分别进行不饱和醛酮,烯烃或硝基苯衍生物的催化加氢反应,并研究了α,β-不饱和醛与醇之间发生加氢-酯化串联反应生成饱和酯的反应活性。具体研究的内容有以下几个方面：在氢气为氢源的加氢体系中,我们研究了嵌段聚合物P123/[BMMIM]OAc离子液体混合胶束稳定的镍纳米颗粒体系,利用多种仪器表征和活性评价等多种研究方法系统考察了催化剂的制备条件、物理化学性质(金属纳米颗粒的尺寸以及表面电荷性质)和催化反应性能之间的相互关系。研究发现,催化剂的制备条件对镍纳米颗粒的活性有很大的影响,如还原温度和稳定剂的量等。将合成的镍纳米颗粒催化剂应用于C=C双键及-N02官能团的水相加氢反应,发现镍纳米颗粒在温和的反应条件下对于烯烃,α,β-不饱和醛酮和硝基苯衍生物都有很高的催化活性及其选择性,镍纳米颗粒在水相加氢体系能循环使用8次而没有明显的催化活性下降。通过表征结果证明即使在催化体系循环5次后,混合胶束稳定的Ni纳米颗粒在水中仍有很高的分散性。并且添加[BMMIM]OAc离子液体可以提高催化体系的碱性,并能提供额外的立体位阻来抑制纳米颗粒的聚集。因此,添加离子液体后能提高催化剂的反应活性和稳定性。通常在使用异丙醇作为氢源的氢转移加氢体系中需加入碱性物质来活化氢源。因此在氢转移反应部分,我们尝试在不添加碱的条件下,使用多相的金纳米催化剂在异丙醇介质中催化羰基化合物的氢转移反应,使该反应更加绿色。通过比较不同的制备方法,载体和还原方法后发现,使用在550℃下焙烧的镁铝水滑石作为载体,金通过尿素沉淀沉积后,NaBH4作为还原剂制得的金纳米颗粒催化剂对于无外碱的氢转移加氢体系具有很好的反应活性及选择性,并且金纳米催化剂具有很高的循环利用性。通过表征发现,镁铝复合氧化物经过水中负载金纳米颗粒后发生再生现象,其结构恢复成层状水滑石结构。金纳米颗粒是以Au0形式负载在水滑石表面的,因此催化剂的活性中心为Au0。对于α,β-不饱和醛与醇之间一步生成饱和酯的加氢-酯化串联反应,一般采用咪唑,噻唑,三唑等催化剂在强碱的作用下脱质子生成卡宾活性物种来催化反应的进行。在加氢酯化部分,我们研究了不同的咪唑离子液体对于加氢酯化反应的催化活性。通过比较发现,Lewis碱性离子液体[BMIM]OAc在不添加强碱的条件下,对于肉桂醛与乙醇间的加氢酯化反应有很高的产率。中性离子液体以及Br(?)nsted碱性离子液体对于这类反应没有催化活性。Lewis碱性离子液体的碱性对于反应的转化率有很大的影响。更多还原

【Abstract】 Hydrogenation reaction is the fundamental reaction for chemical transformation, and it can simply increase the number of hydrogen atoms in organic compounds and make relatively unsaturated organic compounds into saturated organic compounds. Considering the importance of hydrogenation reaction, the development of clean, efficient green hydrogenation reaction system has far-reaching research significance.According to the perspective of green chemistry, we chose green reaction solvents and green catalysts for hydrogenation of the unsaturated aldehydes, ketones, olefins or nitrobenzene derivatives and the hydrogenation related reaction, such as hydrogen transfer reaction, and the redox esterification reaction of α,β-unsaturated aldehydes and alcohols which generated saturated ester. The main research contents have the following several aspects:In hydrogenation reaction by H2as hydrogen donor, the Ni nanoparticles were stabilized by the mixed micelle of the block copolymer P123/[BMMIM]OAc ionic liquids and employed for aqueous phase hydrogenation reaction. It could be demonstrated that the relationship of the preparation conditions and physical-chemical properties (size and surface charge properties of metal nanoparticles) with the performance of Ni catalyst through instrumental characterization and the activity tests of Ni catalysts. It was found that preparation conditions of Ni nanoparticles have great influence on the activity, such as the reduction temperature and the amount of stabilizers and so on. The synthesized Ni nanoparticles showed the excellent catalytic activity and selectivity for the selective hydrogenation of C=C and nitro compounds in the aqueous phase under very mild reaction conditions. And the Ni catalysts can be recycled at least for eight times without significant decrease in catalytic activity. The results of characterization revealed that the mixed micelles stabilized Ni NPs catalysts were highly dispersed in aqueous phase even after five times catalytic recycles. In addition, The addition of ionic liquid ([BMMIm]OAc) can afford the basicity and an additional steric protection from aggregation of Ni NPs, resulting in enhancing stability and catalytic activity of Ni NPs.Generally, it is necessary for adding alkaline substances to transfer hydrogenation reaction system if isopropanol as hydrogen donor. Hence, supported Au nanoparticles was synthesized and applied for transfer hydrogenation in isopropanol without alkaline. Through comparing the different preparation methods, supports and reduction condition, it was found that the calcined MgAl-hydrotalcite under550℃as the support, and supported Au nanoparticles was synthesized through urea deposition precipitation method and then reduced by NaBH4. It was found that the MgAl oxides was regenerated to the MgAl-hydrotalcite structure. The Au0was the active center for the transfer hydrogenation reaction. The Au nanoparticles could be applied for the transfer hydrogenation of aromatic aldehydes, ketones and nitrobenzene derivatives, and showed high catalytic activity and selectivity. Au catalysts could be recycled without significant decrease in catalytic activity.The internal redox esterification of α,β-unsaturated aldehydes and alcohols is usually catalyzed by deprotonation of azolium salts such as thiazolium, imidazolium, and triazolium salts in the presence of bases. In the part of redox esterification reaction, different ionic liquids were applied as catalysts and reaction solvents. It was found that the Lewis basic ionic liquid,1-butyl-3-methylimidazolium acetate ([BMIM]OAc), exhibited the highest activity for this reaction. The neutral and Br(?)nsted basic ionic liquids can not catalyze redox esterification and the base strength have strong effect on the yield of the saturated ester.更多还原