一步水热合成Ag-OMS-2纳米棒及其催化燃烧性能研究

采用水热法一步合成了不同含量的Ag掺杂的氧化锰八面体分子筛(Ag-OMS-2),用X射线衍射(XRD)、比表面积测试(BET)、拉曼光谱(Raman)、扫描电镜(SEM)、氧气程序升温脱附(O2-TPD)和氢气程序升温还原(H2-TPR)等表征手段对催化剂进行了结构和形貌表征,并应用于甲苯的催化燃烧反应,考察了Ag的掺杂量对该反应性能的影响。结果表明:合成的Ag-OMS-2材料属于cryptomelane一维隧道结构,Ag的掺杂并未改变纳米材料的晶体结构;适量比例的Ag的引入促进了晶格氧的流动,降低了还原温度,有利于提高纳米材料的催化性能。5%Ag的样品对甲苯催化燃烧具有最好的催化活性,其起燃温度T10为183℃,完全燃烧温度T90约194℃。     

N-羧甲基新烟碱的合成

以3-氨甲基吡啶和二苯甲酮为主要原料,以甲苯为反应介质和分水剂,以对甲苯磺酸为催化剂,先合成了3-(二苯甲酮缩亚胺基甲基)-吡啶(化合物Ⅰ),再以化合物Ⅰ为原料合成了新烟碱(化合物Ⅱ),最后以化合物Ⅱ为原料合成了新型化合物N-羧甲基新烟碱;并对化合物Ⅰ的合成条件进行了优化,同时探讨了N-羧甲基新烟碱合成过程中溴乙酸乙酯用量对中间产物结构的影响。采用1H NMR和MS等方法对所合成的化合物进行了结构表征。实验结果表明,以甲苯为溶剂,在110.6℃下回流反应4.0 h时,化合物Ⅰ的收率最高可达78.5%;当n(化合物Ⅰ)∶n(二异丙基氨基锂)∶n(顺式-1,4-二氯-2-丁烯)=1∶1.2∶1.5、反应时间3.0 h时,化合物Ⅱ的收率最高为81.5%;N-羧甲基新烟碱的收率为68.5%。     

CO_2－环氧化物－甲苯的汽液平衡及CO_2在体系中的分配

对由ＣＯ２、环氧丙烷、环氧乙烷、聚碳酸亚丙酯、甲苯等构成的７个体系在４０～７０℃的气液平衡作了简易测定和闪蒸计算，结果与用Ｐｅｎｇ—Ｒｏｂｉｎｓｏｎ状态方程法计算的完全一致；计算了ＣＯ２在液相及在整个体系中的浓度比α，发现它与ＣＯ２在单位可占据容积中的质量与温度乘积成线性关系：回归相关系数为－０．９５，式中Ｔ为体系温度（Ｋ），Ｗ１为ＣＯ２总重（ｇ），Ｖｏ、Ｖ１和Ｖ１分别为体系总容积、液相体积和液相中各组分体积（ｍｌ），下标１表示超临界组分ＣＯ２。     

Direct Oxidation of Toluene to Benzoic Acid with Molecular Oxygen over Manganese Oxides

Manganese oxides, which are easily prepared, simple to use and capable of being recycled, have been employed as catalyst in the selective oxidation of toluene to benzoic acid for the first time. Molecular oxygen was used as oxidant under additive- and solvent-free conditions. As a result, 39% conversion of toluene and 93% selectivity of benzoic acid were achieved.     

One-pot synthesis of isobutyl toluene via combined acylation and hydrogenation over Pd–Beta zeolite

The original one-pot synthesis of isobutyl toluene by simultaneous acylation of toluene with acetic anhydride and hydrogenation of the formed isopropyltolyl ketone over Pd–Beta zeolite is described. Zeolite Beta was chosen due to its high acidic activity in toluene acylation with isobutyric anhydride as well as after modification with Pd due to a high activity in hydrogenation of isopropylphenyl ketone to isobutyl benzene. The rate of the formation of isobutyl toluene substantially increases with the hydrophobicity of zeolite Beta despite the “simultaneous” or “consecutive” mode of the experimental setup applied. It is explained by the easier desorption of polar products and faster transport from acid sites to Pd particles, on which the primary formed ketone intermediate is hydrogenated. No effect of hydrogen pressure on the formation of isobutyl toluene was observed, however, with increasing hydrogen pressure hydrogenation of toluene, used as reactant as well as solvent, proceeds at a larger extent.     

Low temperature complete combustion of dilute toluene and methyl ethyl ketone over Mn‐doped ZrO2 (cubic) catalysts

Combustion of dilute toluene and methyl ethyl ketone over Mn‐doped ZrO₂ catalysts prepared using different precipitating agents, such as tetra‐alkyl ammonium hydroxides and NH₄OH, having Mn/Zr ratios from 0.05 to 0.67, and calcined at different temperatures has been thoroughly investigated. The Mn‐doped ZrO₂ catalyst shows high toluene or methyl ethyl ketone combustion activity, particularly when its ZrO₂ is in cubic form, when its Mn/Zr ratio is close to 0.2, and when it is prepared using tetra‐methyl ammonium hydroxide as a precipitating agent and calcined at 773 K. Copyright © 2005 Society of Chemical Industry     

二甲苯砜加入法抑制甲苯磺化副反应

对气相三氧化硫磺化甲苯过程中的副产物二甲苯砜的生成原因及抑制作用机理进行了分析,提出用磺化副产物二甲苯砜自身抑制的新方法。考察了二甲苯砜加入量和甲苯转化率对副反应的抑制作用。反应温度10℃,三氧化硫体积分数6％,甲苯转化率35％时,外加甲苯质量3.3％的二甲苯砜就能控制二甲苯砜含量不增加,且甲苯磺酸对位异构体质量分数由83.35％上升到88.39％,间位异构体质量分数由2.10％下降到1.01％。     

微波辐射下活性炭固载对甲苯磺酸催化合成柠檬酸三丁酯

用活性炭固载对甲苯磺酸作催化剂，在微波辐射下，快速合成了柠檬酸三丁酯。确定了最佳合成条件：微波功率为250W，催化剂用量为1．4g，n(醇)：n(酸)=3．6：1，反应时间40min，在此条件下，酯化率达93．0％。另外通过实验发现，在微波辐射下，酯化反应速率和酯化率均明显高于常规加热方式。     

载体改性对纳米加氢催化剂活性的影响

应用不同的助剂对纳米加氢催化剂的载体进行改性,以甲苯加氢反应为探针,对改性后的纳米加氢催化剂进行了性能测试。运用XRD、SEM方法对改性的纳米加氢催化剂进行表征,研究了载体改性对纳米加氢催化剂活性的影响。结果表明,载体改性细化了催化剂活性组分的粒子,提高了活性组分粒子的分散度,有利于提高纳米加氢催化剂的活性,助剂中TiO2改性的催化剂活性较高且稳定。     

正庚烷-芳烃在加水N-甲酰吗啉溶剂中的液-液平衡

用平衡釜测定了常压、333.15K下正庚烷-苯-（N-甲酰吗啉（NFM） 水）、正庚烷-甲苯-（NFM 水）和正庚烷-对二甲苯-（NFM 水）3个拟三元（四元）体系的液-液平衡数据，得到了拟三元液-液平衡体系的共轭相组成和分配曲线。实验数据用UNIQUAC和NRTL模型进行关联，分别获得了拟三元和四元体系的模型参数。用共轭相作图法和模型参数推算了各体系的褶点数据，一致性良好。通过比较和讨论表明，对相同的正庚烷-芳烃体系，333.15K加水NFM溶剂较无水NFM溶剂萃取更有利于芳烃的回收。