【作者】 郑云锋；

【导师】 马建泰；

【作者基本信息】 兰州大学 ， 物理化学， 2009， 博士

【摘要】 贵金属催化剂反应活性高,但易失活,价格昂贵;镍催化剂虽然初活性较低,但不易中毒,活性比较稳定,价格便宜。在世界范围内,在一些非精细行业已出现了镍催化剂在生产中大量取代贵金属催化剂的趋势。几年前,我们实验室自主开发出了钝化的新型负载镍催化剂,我的工作主要是将我们实验室自制的新型负载镍催化剂进行了一系列表征,探讨其在各种硝基还原反应中的应用。1.新型Ni/SiO₂催化剂还原芳香族硝基化合物的研究芳香胺类化合物及其衍生物用途广泛,是重要的化工中间体。我们用沉积沉淀法和表面钝化技术合成了一种新型的Ni/SiO₂磁性催化剂,并首次将该催化剂用于芳香族硝基化合物合成芳香胺的研究。在催化还原反应中,发现Ni/SiO₂是一种高效,结构稳定,可重复使用的催化剂。并且由于它的相对低活性,不会破坏其它的取代官能团,故适用于多种取代基芳香胺的制备。该催化剂和其它的催化体系相比有以下优点:它能够在423K以下空气氛围中安全储存,并且使用前无需活化;容易制备且价格低廉,易于工业化;反应条件温和;催化体系环境友好,仅用无水乙醇作溶剂;产品易于分离,采用过滤或者磁分离即可;高转化率和高选择性,几乎没有副产品;绝大多数取代基,如-OH,-Cl,-CH₃,-CHO,-CH₂OH,-COCH₃,-OCH₃和-NHCOCH₃等在还原反应中不被破坏。2.新型Ni/SiO₂催化剂一锅法合成亚胺亚胺[imine,schiff base]及其衍生物是重要的有机合成中间体,广泛用于杂环,氨基酸,抗癌试剂和液晶材料的合成。主要有三种合成路线:直接合成亚胺[酸催化和脱水];一锅法氧化合成亚胺[氧化,酸催化和脱水];一锅法还原合成亚胺[还原,酸催化和脱水]。镍类催化剂是硝基还原的优秀催化剂,SiO₂是亚胺合成的常用促进剂,因而Ni/SiO₂很有可能是从芳香族硝基化合物和醛一锅合成亚胺的优良多功能催化剂。我们首次将Ni/SiO₂催化剂用于一锅法合成亚胺的研究。我们找到了反应的最佳条件,探讨了不同的催化体系;在最佳条件下,高产率的合成了大量含复杂取代基的亚胺。预计在杂环,氨基酸,抗癌试剂和液晶材料的合成方面会有较好的运用。催化剂可以方便的回收和重复使用。一锅法合成,无需分离中间产物,减少生产成本,绿色环保。更多还原

【Abstract】 Noble metal catalyst has high reaction activity,but it is deactivated easily and expensive.Nickel catalyst,is very cheap and relatively stable,not easy poisoned, although with a lower initial activity.Nickel catalysts have already had the trend to replace the precious metal catalyst in a number of non-refined industries of the world.In recent years,our laboratory have developed a novel passive supported nickel catalyst,my primary work is making a series of characterizations of the nickel catalyst and exploring its applications in a variety of nitro-reduction reactions.1.A green reduction of aromatic nitro compounds to aromatic amines over a novel Ni/SiO₂ catalystAromatic amines and their derivatives are important intermediates.We have prepared a novel Ni/SiO₂ catalyst by the technologies of deposition-precipitation and surface passivated,and firstly put it into the process of synthesis amine from aromatic nitro compounds.In our experiments,Ni/SiO₂ is found a highly efficient,stable and reusable catalyst for the reduction of aromatic nitro compound.Vary aromatic amines is achieved while using the catalyst,and the probable reason is that the passivated Ni/SiO₂ catalyst has lower activity and doesn’t destroy sensitive groups in comparison with other reported catalysts.The major advantage of this catalyst is as follow:it can be stored safely in air below 423K and need no activation before use;can be easily prepared and scaled up easily;mild reaction conditions;catalytic system is environmentally friendly,ethanol as sole solvent;the product can be conveniently separated using filtration or magnetic separation;high conversion and selectivity,almost without by-products;sensitive functional groups,such as-OH,-Cl,-CH₃,-CHO,-CH₂OH,-COCH₃,-OCH₃ and -NHCOCH₃,remain unaffected in the reaction condition.2.One pot synthesis of imines from aromatic nitro compounds with a novel Ni/SiO₂ magnetic catalystImines and their derivatives are versatile intermediates in organic synthesis,in particular for the preparation of heterocycles,non-natural aminoacids,anti-cancer agents and liquid crystalline materials.There are three main synthesis routes:direct synthesis of imines[acid catalyst and dehydration];one-pot synthesis of imine with oxidation[oxidation,acid catalyst and dehydration];one-pot synthesis of imine with reduction[reduction,acid catalyst and dehydration].Ni compounds are excellent catalysts for the reduction of nitroaromatics and SiO₂ is a commonly-utilized catalyst for imine formation.It seemed promising that Ni/SiO₂ can be an effective bifunctional catalyst for one pot synthesis imines from nitroaromatics.We put it to one pot synthesis imines from nitroaromatics for the first time.We found the optimal reaction conditions,explored different catalyst system;in the best conditions,we have synthesis a large number of imines with vary complex substituents in the optimal conditions.It maybe has good use in the synthesis of heterocycles,amino acids,anti-cancer reagents and liquid crystal material.Catalyst can be conveniently recycled and reused.One-pot synthesis is a method that without separation intermediates,saving costs and environmental friendly.更多还原