【作者】 任一鸣；

【导师】 蔡春；

【作者基本信息】 南京理工大学 ， 应用化学， 2009， 博士

【摘要】 本论文主要研究了分子碘作为催化剂在有机合成反应中的应用。主要研究了碘催化Knoevenagel反应、Henry反应、醛胺缩合反应、氰基化反应、Micheal加成反应、缩醛反应、酯化和酯交换反应。同时,多组分一锅法合成了多取代咪唑衍生物、苯并吡喃衍生物、三芳基取代吡啶衍生物、嘧啶酮衍生物。考察了反应温度、反应时间、催化剂用量、溶剂种类等因素对上述反应的影响。研究表明,分子碘作为催化剂能有效的催化上述反应的进行,并且反应条件温和、后处理简单、反应速度快、产率高。例如,Knoevenagel反应、Henry反应和Micheal加成反应都能在室温下很好的进行反应,并且产率较高,反应时间短。其中Knoevenagel反应在室温下反应2～90min即可完成,产率最高可达到98%;Henry反应在室温下反应2～5h即可完成,产率最高可达到99%;Micheal加成反应在室温下反应2～5h即可完成,产率最高可达到95%。研究了无溶剂或水作为反应介质的环境友好体系中分子碘催化的反应。在水相体系中,探索了Knoevenagel反应、Henry反应、氰基化反应和苯并吡喃衍生物的合成反应。在无溶剂体系中,合成了多取代咪唑衍生物、三芳基取代吡啶衍生物和嘧啶酮衍生物。其中在醛和伯醇的氰基化反应中,用廉价、无毒的化合物NH₄OAc代替了挥发性大、有强烈刺激性的NH₃·H₂O作为绿色的氮源。利用聚乙二醇型中性离子液体(PEG_{2000-IL-PEG400-IL-PEG1000-IL、PEG2000-IL}和甲苯高温一相,低温两相的特点,在PEG-IL/甲苯体系中实现了催化剂分子碘的循环重复利用。成功的把分子碘/PEG-IL体系应用在缩醛反应和酯化和酯交换反应,反应产率较高,含有催化剂分子碘的离子液体相通过简单的相分离,就可循环利用,催化剂可循环使用数次,催化效果无明显降低。初步研究了改性的聚苯乙烯树脂对分子碘的负载,并把负载碘的改性聚苯乙烯树脂应用在Michael加成反应中,没有得到理想的结果。更多还原

【Abstract】 In this dissertation, the catalysis efficiency of molecular iodine for several classic organic reactions was investigated in datails.These model reactions include Knoevenagel condensation, Henry reaction, condensation of aldehyde with amine, cyanation, Michael reaction, synthesis of acetal, esterification and transesterification reaction. Meanwhile, one-pot synthesis of highly substituted imidazoles,5-unsubstituted-3,4-dihydropyrimidin-2（1H）-ones,2-amino-2-chromenes and 2,4,6-triarylpyridines was also explored. The reaction conditions such as reaction temperature,reaction time, addition of I₂, solvents were optimized.The results show that the above-mentioned reactions can be effectively promoted by using molecular iodine as catalyst. Generally, the introduction of molecular iodine can offer the model reactions with milder reaction conditions, simpler experimental procedure while higher yields.For instance, Knoevenagel condensation, Henry reaction and Micheal reaction could be catalyzed by molecular iodine with high yields at room temperature.The highest yield of 98% could be achieved for Knoevenagel condensation within 1.5 h; and 99% yield for the Henry reaction within 5 h and; while 95% yield for Micheal reaction within 5 h.In this dissertation, the catalysis efficiency of molecular iodine was further explored in some model reactions in environmentally benign medium like water or even solvent-free reaction systems. In aqueous medium, Knoevenagel condensation, Henry reaction, cyanation and synthesis of 2-amino-2-chromenes were studied as model reactions. In solvent-free system, the synthesis of highly substituted imidazoles,5-unsubstituted-3,4-dihydropyrimidin-2（1H）-ones and 2,4,6-triarylpyridines was explored.In addition, the direct oxidative conversion of aldehydes and alcohols into nitriles was achieved by using aqueous NH4OAc as a nontoxic cyanide source.NH4OAc is found to be more eco-friendly than s ammonia solution as no gaseous ammonia produces in the reaction.The recovery of molecular iodine catalyst was investigated by using PEG derived ionic liquids (PEG₂₀₀-IL, PEG₄₀₀-IL, PEG₁₀₀₀-IL, PEG₂₀₀₀-IL) and toluene co-solvent system. This co-solvent system shows interesting properties at varying temperature, i.e., heterogeneous at low temperatures and homogeneous at high temperatures （ca 80℃）.By using PEG-derived ionic liquids,the molecular iodine can be effectively recovered in the model reaction such as the synthesis of acetal,esterification and transesterification reaction. The molecular iodine recovered by simple liquid-liquid extraction can be recycled several times （ca 4 times） with consistent reactivity.Finally, the immobilization of molecular iodine was explored by using modified polystyrene resins.The preliminary results indicate that these polymer-supported catalyst was not very stable for Michael reaction and difficult to recover and reuse without losing their catalysis efficiency.更多还原