Liquid-Phase Hydrogenation of Chloronitrobenzene Over Pt-Sn-B Amorphous Catalyst Supported by Carbon Nanotubes

The Pt-Sn-B/carbon nanotubes (CNTs) catalyst was prepared by impregnation-chemical reduction method. Its catalytic performance was evaluated by liquid-phase hydrogenation of chloronitrobenzene (CNB). The results showed that the catalyst had higher catalytic performance than common hydrogenation catalysts. The conversion of CNB could reach 99.9%, and the dechlorination of chloroaniline (CAN) was less than 1.9% when catalyzed by Pt-Sn-B/CNTs and more than 8.0% when catalyzed by common hydrogenation catalysts. X-ray diffraction and selected area electron diffraction analysis showed that Pt-Sn-B/CNTs had an amorphous alloy structure that can improve catalytic performance. Transmission electron micrograph image showed that the catalyst particles were highly distributed on the surface of CNTs. The hydrodechlorination of CNB was mainly affected by the unique structure of CNTs and the nature of the amorphous metals on the surface of CNTs. The relationship between the interaction of CNTs and amorphous metals and the catalytic performance of the catalyst is also discussed. Translated from the Chinese Journal of Catalysis, 2005, 26(3) (in Chinese)     

负载型镍基非晶态催化剂催化氯代硝基苯加氢合成氯代苯胺

分别以碳纳米管(CNTs), SiO_2, TiO_2, γ-Al_2O_3, TiO_2-SiO_2和活性炭(AC)为载体(M),以Ni和B为活性组分,采用浸渍-化学还原法制备了一系列负载型Ni-B非晶态合金催化剂(Ni-B/M).采用电感耦合等离子体光谱(ICP), XRD, TEM和DSC研究了Ni-B/CNTs的非晶性质,Ni的担载量及其热稳定性.将Ni-B/M用于催化三种氯代硝基苯液相加氢合成氯代苯胺的反应.结果表明,Ni-B/M在反应中表现出较高的活性和良好的选择性,其中Ni-B/CNTs可使三种氯代硝基苯的转化率均高于99.8%,加氢脱氯率小于3%.讨论了CNTs和Ni-B之间的相互作用对催化剂性能的影响.     

水溶性Ru-TPPTS配合物催化对-氯硝基苯选择性加氢

研究了水／有机两相催化体系中,水溶性Ru-TPFrS配合物催化对-氯硝基苯中硝基的选择性加氢反应。考察了溶剂种类、水溶液的pH值、添加助剂三乙胺、水／有机两相体积、底物浓度等对对-氯硝基苯转化率和生成对-氯苯胺选择性的影响,并在90℃、4.0MPa、反应时间为6h的条件下,进行了催化剂的循环实验。     

Influence of alloying platinum for the hydrogenation of chloronitrobenzene over PtM/ZrO2 catalysts with M=Cr, Mn, Fe, Co, Ni, Cu

Hydrogenation of chloronitrobenzene (CNB) over PtM/ZrO₂ (M= Cr, Mn, Fe, Co, Ni, Cu) catalysts has been studied in ethanol at 303 K and normal pressure. The results show that the hydrogenetion of CNB can be carried out over PtM/ZrO₂ catalysts. The order of the hydrogenation rates of CNB is p>m>o, and the yield of chloroaniline (CAN) is p>o>m. PtFe/ZrO₂ catalysts shows the highest catalytic activity on the hydrogenation of CNB. PtNi/ZrO₂ catalyst shows good yield of CNB to CAN, and 93.3 mol% for o-CAN, 98.0 mol% for m-CAN and 98.5 mol% for p-CAN, respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synergism in catalytic halogen-exchange fluorination of 4-chloronitro- and dichlorotetrafluorobenzenes

Synergism was studied in catalytic halogen-exchange fluorination of 4-chloronitro- and dichlorotetrafluorobenzenes. The synergistic effect in the fluorination of chloroaromatic compounds with potassium fluoride was mainly attributed to separation of the activation functions of catalysts with respect to substrate molecules.     

Ni-Ce-P非晶态合金催化剂用于氯代硝基苯液相加氢制氯代苯胺

 采用化学还原法制备了Ni-Ce-P非晶态合金催化剂,用X射线能谱、 X射线衍射、 选区电子衍射、 透射电子显微镜和差热分析等方法对催化剂的组成、结构、形貌及热稳定性进行了表征,讨论了Ni-Ce-P非晶态合金催化剂的催化性能和结构的关系,并以氯代硝基苯液相加氢合成氯代苯胺为探针反应考察了所制备催化剂的加氢性能. 研究结果表明,在不加脱卤抑制剂的情况下,在110 ℃下反应时所选4种反应物的转化率均可达99.8%, 脱卤率小于1.8%, 且Ni-Ce-P非晶态合金的活性为Ni-P非晶态合金催化剂的2倍,表现出较高的加氢性能和抑制脱卤性能.     

Thermische Analyse der Reaktivität vono- undp-Chlornitrobenzen

Because there is risk of autocatalytic reduction, the conversion of chloronitrobenzene with alkaline alcohol is important in safety management. The influence of several parameters on the reaction will be described. The experiments were realized in a non commercial calorimeter, equipped with for the precision calorimeter ACTRON developed hard- and software. For the non-linear kinetic evaluation of the experiments the program TA-kin was used.It could be ascertained, that the calorimetry is applicable for the investigation of the influence of parameters on the conversion of chloronitrobenzene.

     

Application of a new type of safety calorimeter

Safety production in chemical plants is a high-priority task, especially as concerns reactions which can change mechanism suddenly under defined conditions, e.g. from a simple well-defined to an undesired autocatalytic reaction. An example of this kind, the reaction of chloronitrobenzene with alkaline alcohol, was investigated with the new adiabatic precision calorimeter ACTRON 5, designed with a safety concept. It is shown that the reaction can be interrupted safely under predicted conditions.     

壳聚糖多孔微球负载PdCl2选择性催化氢化氯代硝基苯的研究

以壳聚糖为原料，液体石蜡为分散介质，甲醛，戊二醛为交联剂，通过反相悬浮交联制备了粒径小于100μm的壳聚糖多孔微球；对制备壳聚糖多孔微球的影响因素进行了探讨，并用FTIR和SEM表征了多孔微球；XPS表明，壳聚糖多孔微球经PdCl2负载后，PdCl2与壳聚糖形成配合物，配位键是在PdCl2的Pd与壳聚糖的N之间形成。在常温常压下，PdCl2/壳聚糖多孔微球能选择性地催化还原氯代硝基苯为氯苯胺；对影响催化加氢的因素如反应温度、溶剂、催化剂用量和底物浓度作了探讨。     

水溶性纳米ni催化氢化氯代硝基苯制备氯代苯胺

水溶性纳米镍;催化加氢;氯代硝基苯;氯代苯胺