【作者】 施颖；

【导师】 胡家元；

【作者基本信息】 四川大学 ， 分析化学， 2004， 硕士

【摘要】 以分子氢作为氢源,在液相、气相催化体系中运用金属配合物和金属负载催化剂,高效率、高选择性地氢化有机底物一直是催化领域中最具理论与实用价值的前沿课题之一。2-(2,5-二甲氧基苯基)硝基乙烯(简称DMPNE)是一种重要的化工原料,其加氢产物2,5-二甲氧基苯基乙胺(简称DMPEA)广泛应用于有机合成、精细化工和医药中间体。寻找适于DMPNE加氢反应的催化体系是很具挑战性的课题。本论文综述了催化加氢的研究现状,特别是液相催化体系对硝基芳烃加氢的研究进展。运用水溶性膦配体TPPTS(三-间磺酸钠-三苯基膦),研究了在加压条件下RuCl3-TPPTS原位催化DMPNE加氢制备DMPEA的反应性能;同时还研究了金属负载催化剂在加压条件下,催化液相中的DMPNE加氢生成DMPEA的反应性能,取得了较为满意的结果。制备了Ru/C、Ru-Pd/C、Ru/Al2O3、Ru-Pd/Al2O3等负载型催化剂,采用BET法测定活性碳表面积,对Ru/C和Ru-Pd/C等催化剂进行了XRD、XPS表征。系统研究了上述催化剂以分子氢为氢源,催化DMPNE加氢反应的性能,反应产物经GC-MS分析,主要产物为DMPEA、2-(2,5-二甲氧基苯基)胺基乙烯和2-(2,5-二甲氧基苯基)硝基乙烷,其中DMPEA含量最高。结果表明,当Ru的浓度为4 mmol/L、[TPPTS]/[Ru]摩尔比=6、H2分压为4.0 MPa、反应温度为90 ℃时,延长反应时间不仅能进一步提高底物转化率,且可以获得纯度较高的C=C加氢与—NO2完全加氢的目标产物;此条件下无苯环加氢副产物<WP=6>生成。在液/固两相催化体系中,运用5%Ru/C,在催化剂:底物=1:5(质量比)、H2分压为5.0 MPa、反应温度为150℃、反应时间为5h时,可以获得纯度较高的目标产物DMPEA;以Ru-Pd/C为催化剂(Ru负载量为4wt%;Pd为1wt%),在最佳条件下只需反应5h底物转化率就可达100%,生成目标产物的选择性最高达84%;以Ru/Al2O3作催化剂(Ru负载量5 wt %),在适当的条件下,150℃时底物转化率可达96.0%,而选择性很低,170℃时转化率达变化不大选择性最高达35.2%;以Pd/C、Ru-Pd/Al2O3作催化剂,在优化条件下转化率都在90%以上,但选择性不高。更多还原

【Abstract】 The high effective and selective hydrogenation of organic substrates with molecular hydrogen and metal complex as catalyst is one of the most interesting and challenging topics in catalytic frontier. 2-(2,5-Dimethoxyphenyl)nitroethene (DMPNE) and its hydrogenation product 2,5-Dimethoxyphenethylamine(DMPEA) are wildly used in fine chemical synthesis and medicine intermediate. The developments of catalytic hydrogenation, especially the hydrogenation of nitrobenzene are reviewed. TPPTS [P(C6H4SO3Na)3] have been synthesized. With molecular hydrogen as reductive, the DMPNE hydrogenation catalyzed by RuCl3-TPPTS has been investigated in autoclave. The catalytic performance of Ru/C, Ru-Pd/C, Ru/Al2O3, Ru-Pd/Al2O3 in the hydrogenation have been also studied. A series of new and useful results with application prospect have been obtained. Ru/C, Ru-Pd/C etc. have been synthesized and their structures have been confirmed by BET, XRD, XPS.With molecular hydrogen as reductive, the performance of RuCl3-TPPTS as catalyst precursor for selective hydrogenation of both C=C and -NO2 groups in DMPNE have been studied in biphasic catalytic system (aqueous/organic phase). Their hydrogenation products have been analyzed by GC-MS, the main product is DMPEA. The conversion and the selectivity for hydrogenation of both C=C and -NO2 groups both increase after a long time reaction when the reaction conditions are [Ru]= 4mmol/L, [TPPTS]/[Ru]mol ratio=6,PH2=4.0MPa and 90 ℃. <WP=8>Hydrogenation of aromatic ring is not found to occur (or does not occur). The addition of a surfactant (CTAB: cetyltrimethylammonium bromide) rather decreases the hydrogenation activity as well as the selectivity for hydrogenation of both C=C and -NO2 groups although the surfactant (CTAB) would increase hydrogenation activity in general. It is suggested that the steric hindrance of the surfactant micelle formed may decrease the solubility of DMPNE in biphasic catalytic system. Under the best reaction conditions, the conversion of substrate is 98.0%. It’s easy to separate the hydrogenation product from the catalyst after the reaction .In biphasic catalytic system (liquid/solid phase), the conversion rises and the selectivity for hydrogenation of both C=C and -NO2 groups increases after 5 hours reaction when the reaction conditions are Ru = 0.049mmol, PH2=5.0MPa and 150 ℃. Under optimized condition, the conversion of DMPNE hydrogenation catalyzed by Ru-Pd/C, Ru/Al2O3, Ru-Pd/Al2O3 reaches 90% but the selectivity of DMPEA is lower.更多还原