【作者】 刘丽荣；

【导师】 吕春绪；

【作者基本信息】 南京理工大学 ， 精细化工， 2009， 博士

【摘要】 固体酸和离子液体催化有机合成反应是化学化工领域的研究热点之一。在反应体系中加入合适的固体酸和离子液体催化剂,可以提高反应的收率和选择性。甲苯硝化是非常重要的精细有机合成反应,将固体酸和酸性离子液体催化剂应用于芳烃的选择性硝化,是正在兴起的绿色化学合成技术之一。针对工业上采用的传统混酸硝化法所存在的对设备腐蚀严重、可造成环境污染及对硝基甲苯选择性过低等问题,分别讨论了各种固体酸和酸性离子液体对甲苯硝化反应的催化作用。主要工作及结果如下:（1）研究了固体铌酸及其改性物催化甲苯的选择性硝化反应,结果分析表明,改性铌酸催化剂对甲苯硝化均表现出了比铌酸催化剂更强的区域选择性,其催化甲苯硝化反应的催化活性相对次序与它们各自的酸强度大小呈正相关关系。（2）研究了ZrO₂-TiO₂/SO₄^2-固体超强酸催化甲苯的选择性硝化反应。分析了催化剂锆、钛原子比、焙烧温度、用量、硝化反应条件以及催化剂的重复使用等因素对甲苯硝化反应选择性的影响,确定了最佳硝化条件。（3）研究了不同种类Keggin型杂多酸对甲苯硝化反应选择性的影响。结果表明,相同条件下,杂多酸催化甲苯硝化反应的活性大小顺序与其酸强度次序一致,即:磷钨酸＞硅钨酸＞钼磷酸。（4）利用酸式盐——硫酸氢钠、磷酸二氢钠、磷酸二氢钾作为甲苯选择性硝化反应的催化剂,研究了催化剂用量、硝化反应时间、温度以及催化剂的循环使用等因素对甲苯硝化反应选择性的影响,取得了令人满意的结果。（5）将HNIL·NO₃^-和HNIL·HSO₄^-新型酸性离子液体应用于甲苯的选择性硝化,效果良好。尤其是HNIL·HSO₄^-酸性离子液体的催化活性更是显著提高,这主要是由于HNIL·HSO₄^-酸性离子液体酸性更强的缘故。（6）采用现代方法对所选择和制备的催化剂进行了表征。硝化反应研究结果表明,上述催化剂均能显著提高甲苯硝化产物的对位选择性和收率,甲苯硝化产物邻/对比在0.88-1.20之间变化,收率可达82.5-100%。（7）研究了固体酸和酸性离子液体催化甲苯选择性硝化反应的机理。反应共分两部进行:第一步是快速的预平衡步骤,活性硝化剂转移至催化剂上;第二步是缓慢的速率控制步骤,粘结在催化剂上的活性硝化进攻试剂与底物反应生成目标产物。更多还原

【Abstract】 Using solid acids and ionic liquids as catalysts in organic synthesis was one of the important research fields in chemistry and chemical engineering.By adding suitable solid acids and ionic liquids as catalyst in reaction systems,the reaction yield and selectivity could be improved.Nitration of toluene was one of the most important fine organic synthesis reactions,Using solid acids and acidic ionic liquids for the nitration of aromatic compounds was one of the technologies for rising green chemical synthesis.The industrial nitration of toluene to synthesize p-mononitrotoluene（p-MNT） involving the concentrated mineral acids as the catalyst which is one of the most environmentally harmful processes.The process produces huge amounts of wastes along with a large amount of undesired o-MNT due to the nonselective nitration of toluene.Catalysis affect of solid acid and acidic ionic liquids on nitration of toluene were discussed.The main works and results were as follows:（1）The nitration of toluene catalyzed by Solid niobic acid catalyst and its modifiers was studied.Higher regioselectivy of toluene in mononitration in the Presence of all kinds of modified niobic acid than unmodified one,and the positive correlation of its acid strength and catalytic activity were discovered.（2）The regioselective nitration of toluene with ZrO₂-TiO₂/SO₄^2- solid acid catalysts was investigated.The effect of all kinds of factors,just like calcinations temperature,dosage of catalyst,atom ratio of Zr and Ti,nitrated reaction conditions and recovered of catalyst,etc.on the regioselectivities of toluene in mononitration were researched and the best nitration condition was established.（3）Effects of different kinds of catalysts with Keggin structure on nitration of toluene were studied.It was found that,in the same condition,catalytic activity of heteropolyacids accords with its acid strength,that is phosphotungstic acid＞silicotungstic acid＞phosphomolybdic acid.（4）Utilizing acidic solt catalysts-sodium bisulfate,sodium dihydrogen phosphate, and potassium dihydrogen phosphate as catalyst of nitration of toluene,the effect of dosage of catalyst,nitrated reaction time and temperature and recovered of catalyst, etc.on the regioselectivities of the nitration of toluene were researched,and the satisfactory result was acquired.（5）Using new acidic ionic liquids catalysts-HNIL·NO₃^-and HNIL·HSO₄^-for the nitration of aromatic compounds had a good effect.Especially catalytic activity of HNIL·HSO₄^-acidic ionic liquids heightened greatly,due to the still stronger acidity of it.（6）These catalysts were characterized by means of modern analyses.It was found that the selectivity and yield of toluene nitration were evidently enhanced,The ortho-para-isomer ratios,in product distribution of toluene mononitration and yield were varied in range from 0.88 to 1.20 and from 82.5%to 100%on above-mentioned solid acids and ionic liquids catalysts.（7）The mechanism of selective nitration of toluene on solid acids and acidic ionic liquids was researched.The total reaction could be explained by two steps.The first was a fast pre-equilibrium,activation nitrating reagent transferred to the catalyst. The second step was slow and rate-determining,activation nitrating reagent bonded on catalysis with reactant and the object product was gained.更多还原