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1.
Effect of Substituents on Nitrobenzene Reduction in the Presence of a Platinum Catalyst 总被引:3,自引:0,他引:3
The effect of substituted nitrobenzene structure on the kinetics of their catalytic reduction in propanol-2 in the presence of a platinum catalyst is studied. The reaction order with respect to a nitro compound changes in the series of the studied substrates. A satisfactory correlation between the apparent rate constants for the reaction and the E
LUMO values of the substrates is observed for several nitro compounds. 相似文献
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Reduction of Nitrobenzene to Aniline with Carbon Monoxide and Water in the Presence of the PdCl2/Fe/I2 System 总被引:2,自引:0,他引:2
Jadwiga Skupi:ska Agnieszka Zukowska Adam Chajewski 《Reaction Kinetics and Catalysis Letters》2001,72(1):21-27
A study of modified catalyst systems composed of palladium or its chloride and a co-catalyst such as metallic Fe-powder, iodine, and pyridine was used in the reduction of nitrobenzene to aniline with carbon monoxide and water at 180°C and 2.5-4 MPa pressure. The reaction is complete in 2 h with a nitrobenzene conversion of 98-100% and a 100% selectivity with respect to aniline. 相似文献
4.
T. Miki T. Higashimura S. Okamura 《Journal of polymer science. Part A, Polymer chemistry》1967,5(12):2989-2996
The amounts of tetraoxane produced in the polymerization of trioxane catalyzed by BF3·O(C2H5)2 were measured in various solvents. The maximum amount of tetraoxane produced depends on the nature of solvent used. This amount was independent of the initial concentration of the catalyst in ethylene dichloride and in nitrobenzene. On the other hand, in benzene, the amount of tetraoxane produced decreased slightly with increasing initial catalyst concentration. This result was explained by the reaction of tetraoxane produced with the residual catalyst as well as with the active center. The maximum amount of tetraoxane produced decreased, other conditions being similar, in the order, nitrobenzene > ethylene dichloride > benzene solvent. This order may be explained in terms of a longer lifetime of the active center in the more polar solvent, leading to the formation of tetraoxane. 相似文献
5.
Richner G van Bokhoven JA Neuhold YM Makosch M Hungerbühler K 《Physical chemistry chemical physics : PCCP》2011,13(27):12463-12471
The three-phase hydrogenation of nitrobenzene catalysed by nanosized gold over titania was investigated in a slurry. Simultaneous in situ ATR-FTIR monitoring of the liquid phase and at the solid/liquid catalyst interface identified the species adsorbed on the catalyst and those in the liquid phase during the reaction. Nitrosobenzene was not detected analytically while the spectroscopic measurements strongly indicated phenylhydroxylamine as an intermediate reacting before desorbing from the catalyst surface. Under the same reaction conditions, azobenzene and hydrazobenzene were identified as intermediates during the hydrogenation of azoxybenzene to aniline. When nitrosobenzene or phenylhydroxylamine was alternately fed as reactant, azoxybenzene was produced via a disproportionation route. With the former, azoxybenzene was not further reduced by hydrogen because nitrosobenzene deactivated the catalyst. Combined with H(2) uptake, the spectroscopic measurements provided new insights into the reaction mechanism of the gold catalysed hydrogenation of nitrobenzene and an update of the corresponding kinetics. 相似文献
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制备了聚N-乙烯基吡咯烷酮分散钯催化剂,考察了它对不同底物的加氢活性和在不同介质中对丙烯酸甲酯的加氢活性。结果表明,不同底物的加氢活性和反应级数都有很大的差别,且反应介质对丙烯酸甲酯的加氢速率也有很大影响。还得到了丙烯酸甲酯加氢反应的速率方程。 相似文献
8.
B. J. Jia J. T. Zhou A. L. Zhang W. L. Liu X. R. Song 《Russian Journal of Electrochemistry》2007,43(3):296-300
Taking nitrobenzene as a model, electrochemical heterogeneous catalytic degradation of organic pollutant is investigated using
a novel electrochemical heterogeneous catalytic reactor coupled by three-dimensional electrode with heterogeneous catalytic
reactor. The nitrobenzene removal efficiencies considerably depend on the applied potential, initial pH, and the concentration
of the supporting electrolyte. The results show that, with catalyst the nitrobenzene removal efficiencies are higher than
that of control (without catalyst). The efficiency of ferrous catalyst is the best for nitrobenzene removal especially. It
is clear that the reaction of electro-oxidation is promoted by the catalyst. A possible mechanism of nitrobenzene degradation
is deduced based on products.
Published in Russian in Elektrokhimiya, 2007, Vol. 43, No. 3, pp. 313–318.
The text was submitted by the authors in English. 相似文献
9.
The reaction kinetics of bisphenol-S epoxy resin with methyl-acrylic acid in the presence of quaternary ammonium salt catalyst was studied. The reaction rate constants at different temperatures were determined. The reaction is first order with respect to epoxy group, zero order with respect to methylacrylic acid and 0.71 order with respect to quaternary ammonium salt catalyst, respectively. The mechanism of this reaction was discussed. 相似文献
10.
《Reaction Kinetics and Catalysis Letters》1995,54(1):59-64
Modified catalyst systems composed of palladium or its chloride and co-catalysts such as FeCl3, Fe2O3, metallic Fe-powder, metallic Fe-wire net, iodine, pyridine or aniline, applied in the reduction of nitrobenzene to aniline in the presence of carbon monoxide and water are described. The reaction proceeds at 150–180 °C and 2.5–7 MPa gauge pressure. After 1–7 h the reaction was complete, reaching nitrobenzene conversions of 98–100%. Selectivity of the reaction with respect to aniline was also 100%. 相似文献
11.
以氯化锡为原料,四丙基溴化铵为表面活性剂水热法制备纳米二氧化锡(SnO2)催化剂,并以钛网为基材,制备催化电极. 应用SEM,XRD等手段对催化剂进行表征. 考察了反应物浓度、反应温度和反应时间对催化剂形貌的影响. 研究了纳米SnO2催化剂对锌还原硝基苯原电池反应的电催化性能. 结果表明,当 NaOH浓度为0. 5 mol•L-1、水热反应温度160 ℃、水热反应时间15 h时,得到的SnO2催化剂是由纳米片构成的刺球状颗粒,粒径最小,约17 nm. 与平板铂电极相比,制备的催化电极对硝基苯电还原具有更高的催化活性,硝基苯转化率为74%,最大放电功率为21.9 mW•cm-2,远大于平板铂电极. 硝基苯的主要还原产物为苯胺、对乙氧基苯胺和对氯苯胺. 相似文献
12.
The kinetics of reaction of bromo-epoxy resin with oleic acid in the presence of dimethylbenzylamine catalyst was studied. The reaction is a zero order reaction with respect to oleic acid, first order with respect to epoxy group and 0. 74 order with respect to dimethylbenzylamine. The reaction rate constants at various temperatures and activation energy were determined. The mechanism of this reaction was discussed. Keywords Tetrabromobisphenol-A, Bromo-epoxy resin, Oleic acid kinetics, Reaction mechanism 相似文献
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在5%Cu-5%Pd/γ-Al2O3催化剂作用下,由硝基苯和乙醇反应一锅法合成了2-甲基喹啉.实现了乙醇与硝基苯转移加氢、乙醛缩合、苯胺与不饱和醛加成、脱水环化、脱氢等多步反应的耦合.极大地简化了2-甲基喹啉的合成工艺.相比较传统的化学合成方法,由于避免了使用无机酸碱或均相金属络合物作为催化剂,该方法环境更加友好,解决了均相金属络合物催化剂分离、回收困难的问题.在优化的反应条件:使用1g催化剂,硝基苯15mL,乙醇60mL,水30mL,T=453K,P=3.5MPa,反应时间为12h时,2-甲基喹啉的收率达66.4%. 相似文献
15.
The feasibility of photocatalytic reduction of nitrobenzene using titanium dioxide powder as photocatalyst, under the protection of nitrogen and presence of hole scavenger conditions, was studied. Effects of the illumination time, amount of catalyst and sorts of solvent on the photocatalytic reduction of nitrobenzene were investigated, respectively. The results showed that, for the photocatalytic reduction of nitrobenzene, aniline was the main product. When the illumination time was 6 h, 8.15×10?4 mol/L of nitrobenzene could be photocatalytically reduced completely, with the yield of aniline being 88.5%. The optimum amount of TiO2 used was 4.0 g/L, the optimum initial pH value of reaction solution was 4.0 and the best solvent was methanol. The kinetics and mechanisms of the photocatalytic reduction of nitrobenzene were also discussed. 相似文献
16.
The kinetics of the bulk catalysed and uncatalysed polycondensations of oligomeric ωω′ dihydroxy polyethers and ωω′ diacid polyesters are studied. A model reaction (condensation of octadecanoic acid with 1-octadecanol) is studied under the same conditions. For the model, without catalyst, the reaction order depends on the pressure. When a protonic catalyst is present, the reaction is second order and in the presence of Ti(OBu)4 the overall order is 1 with respect to the reactants and 0.5 with respect to the catalyst. These results are compared to those of previous workers. For the oligomers, in the absence of added catalyst, the reaction is second order with respect to the acid and first order with respect to the alcohol; in the presence of Ti(OBu)4, the reaction is first order with respect to the reactants. The rate constants and the activation enthalpies are reported. 相似文献
17.
The series of cobalt(II) complexes with different Schiff base ligands was synthesized and used as catalyst for the redox carbonylation
of aniline and nitrobenzene. Effects of reaction temperature, CO pressure, promoter, and catalyst additions on the conversion
of substrate were studied. When Co[(OH)2saloph] — p-toluenesulfonic acid system was used as catalyst, the reaction was carried out at the next conditions: both Co[(OH)2saloph] and p-toluenesulfonic acid—0.2 mmol, aniline—20 mmol, nitrobenzene—10 mmol, methanol—30 ml, Co—5 MPa, temperature 170°C, reaction
time 7 h. The highest conversion of nitrobenzene and selectivity of methyl N-phenyl carbamate were 54.5 and 92.2%, respectively. 相似文献
18.
Ľubomír Pikna Mária Heželová Silvia Demčáková Miroslava Smrčová Beatrice Plešingerová Michal Štefanko Mária Turáková Milan Králik Pavel Puliš Peter Lehocký 《Chemical Papers》2014,68(5):591-598
The effect of two types of catalysts on the activity of the catalytic hydrogenation of nitrobenzene was studied. Catalysts were prepared by the surface deposition of palladium hydroxide with a simultaneous reduction with formaldehyde in a basic environment and were characterised by X-ray powder diffraction, transmission electron microscopy, adsorption-desorption, and catalytic tests — hydrogenation of nitrobenzene in methanol. The influence of the supports’ (activated carbon and a mixture of activated carbon and multi-walled carbon nanotubes) surface area is discussed. Despite having a size comparable (4–5 nm) to crystallites of metallic palladium, the catalyst prepared on a mixture of activated carbon and nanotubes (Pd/C/CNT) was significantly less active than the catalyst prepared on pure activated carbon (Pd/C); the rate of this reaction was approximately 30 % lower than the initial reaction rate. This feature could be attributed to the lower specific surface area of the Pd/C/CNT (531 m2 g?1) in comparison with the Pd/C (692 m2 g?1). 相似文献
19.
氯甲基化交联聚苯乙烯(CMCPS)微球的氯甲基与苯甲醛衍生物2-羟基-3-甲氧基苯甲醛(HMBA)发生傅克烷基化反应,形成改性微球HMBA-CPS;微球HMBA-CPS与环己二胺发生席夫碱反应,形成键合Salen配基的微球Salen-CPS;最后,使之与锰盐发生配位螯合反应,制得了固载有手性Mn(Ⅲ)-Salen配合物的固体催化剂Mn(Ⅲ)Salen-CPS,分别采用红外光谱、紫外/可见吸收光谱及扫描电子显微镜对固体催化剂的结构与形貌进行了表征和观察。 研究了微球CMCPS与HMBA之间傅克烷基化反应的规律。 结果表明,以AlCl3为Lewis酸催化剂,使用二氯甲烷与硝基苯混合溶剂,可有效地实施CMCPS与HMBA的傅克烷基化反应,制得固体催化剂Mn(Ⅲ)Salen-CPS。 在V(CH2Cl2)∶V(NB)=10∶1的混合溶剂中,40 ℃下反应10 h,可制得氯甲基转化率近于51%的改性微球HMBA-CPS。 该制备途径具有简便、高效与快捷的特点。 相似文献
20.
Hajrija ehovi Aia Sendijarevi Vahid Sendijarevi Kurt C. Frisch 《Journal of polymer science. Part A, Polymer chemistry》1989,27(4):1287-1299
The cyclotrimerization of model aliphatic and cycloaliphatic isocyanates (butyl and cyclohexyl isocyanate) was carried out using an ammonium carboxylate and a salicylaldehyde-potassium complex as catalysts. The kinetics of the cyclotrimerization of butyl isocyanate in both 2-ethoxyethyl acetate and dimethylformamide (DMF) using the 2-ethylhexanoate salt of trimethylaminopropanol-2 was found to be of first order with respect to the isocyanate and also of first order with respect to the catalyst. The reaction rate in DMF was considerably greater than in 2-ethoxyethyl acetate, as could be expected. Employing the salicylaldehyde-potassium catalyst, the cyclotrimerization of butyl isocyanate followed second-order kinetics with respect to the isocyanate and first order with regard to the catalyst. Due to the fact that the cyclotrimerization of cyclohexyl isocyanate was found to be slower than that of butyl isocyanate, the cyclotrimerization of this isocyanate was carried out only in DMF using the 2-ethylhexanoate salt of trimethylaminopropanol-2 as the catalyst. The kinetics of this reaction was found to follow second order with respect to the isocyanate and first order with regard to the catalyst. The products of the reactions were identified by IR, 1H-NMR, and mass spectrometry. 相似文献