Pt／C催化邻硝基氯苯加氢反应的动力学研究

The kinetics of catalytic hydrogenation of ortho-nitrochlorobenzene to 2,2‘-dichloroazoxybenzene on platinum/carbon catalyst is investigated in a slurry reactor with the temperature range of 313--343 K, and orthochloroaniline is formed as a byproduct. Models based on Rideal-Eley and Langmuir-Hinshelwood mechanism have been proposed based on the rate data and the kinetic regime. The former model can be used to fit the experimental data better. Reaction controlling steps are physical adsorption of hydrogen and adsorbed ortho-nitrochlorobenzene reacted on the surface of catalyst.     

Hydrogenation of naphthalene on NiMo- Ni- and Ru/Al2O3 catalysts: Langmuir–Hinshelwood kinetic modelling

The importance of the hydrodearomatisation (HDA) is increasing together with tightening legislation of fuel quality and exhaust emissions. The present study focuses on hydrogenation (HYD) kinetics of the model aromatic compound naphthalene, found in typical diesel fraction, in n-hexadecane over a NiMo (nickel molybdenum), Ni (nickel) and Ru (ruthenium) supported on trilobe alumina (Al₂O₃) catalysts. Kinetic reaction expressions based on the mechanistic Langmuir–Hinshelwood (L–H) model were derived and tested by regressing the experimental data that translated the effect of both naphthalene and hydrogen concentration at a constant temperature (523.15 and 573.15 K over the NiMo catalyst and at 373.15 K over the Ni and Ru/Al₂O₃ catalysts) on the initial reaction rate. The L–H equation, giving an adequate fit to the experimental data with physically meaningful parameters, suggested a competitive adsorption between hydrogen and naphthalene over the presulphided NiMo catalyst and a non-competitive adsorption between these two reactants over the prereduced Ni and Ru/Al₂O₃ catalysts. In addition, the adsorption constant values indicated that the prereduced Ru catalyst was a much more active catalyst towards naphthalene HYD than the prereduced Ni/Al₂O₃ or the presulphided NiMo/Al₂O₃ catalyst.     

钯催化剂2-乙基蒽醌加氢滴流床反应器模拟

引　言过氧化氢 (H2 O2 )是一种性能优良的氧化剂 ,因其以水为还原产物而备受绿色化学与化工研究领域广泛关注 .以过氧化氢为氧化剂的氧化过程具有反应条件温和、选择性高、无污染等优点 ,因此被广泛用于造纸、印染、化学合成、环境保护和半导体等工业领域 .其应用前景十分广阔     

Ni－W／F－Al_2O_3－SiO_2催化剂的表面吸附维

Ｎｉ－Ｗ／Ｆ－Ａｌ_２Ｏ_３－ＳｉＯ_２催化剂的表面吸附维朱建军，林西平（江苏石油化工学院，化工系，常州，２１３０１６）关键词表面吸附，分形维，Ｎｉ－Ｗ／Ｆ－Ａｌ_２Ｏ_３－ＳｉＯ_２催化剂１引言催化现象与多相催化剂的表面性质密切相关，催化剂表面形状是影响...     

复合固体超强酸SO_4~(2-)/TiO_2-ZrO_2催化合成富马酸二甲酯

合成并表征了新型的复合无机固体超强酸SO2 -4 /TiO2 ZrO2 催化剂 ,用正交试验方法研究了催化富马酸与甲醇反应合成富马酸二甲酯 (DMF)的反应条件 ,同时考察了催化剂活化温度与催化活性之间的关系。实验结果表明 :反应物富马酸与甲醇摩尔配比 1∶6 ,催化剂活化温度为 5 5 0℃ ,催化剂用量 2 .0 % (反应物总质量 ) ,反应时间 6h ,DMF平均收率 91.2 %。     

Catalytic Oxidative Decomposition of Hydrazine in Vapor Phase over Nanosized Au/γ‐Al2O3

The catalytic activity of nanosized Au/γ‐Al₂O₃, synthesized by a deposition‐precipitation process, on oxidative decomposition of hydrazine in air is discussed. The catalyst exhibited an excellent activity at low temperatures. The activity was strongly dependent upon the gold cluster size. The impacts of certain pertinent operating parameters including the particle size of the catalyst, temperature, hydrazine concentration, and feed flow rate on the extent of the reaction were investigated. The results were reproducible with a mean absolute deviation of 3 %. Deactivation of the catalyst during the reaction was found to be unlikely. Finally, a kinetic model based on the Eley‐Rideal formulation was proposed for the reaction and a correlation was made between the data predicted from the model and those determined experimentally.     

Catalyst design using artificial intelligence: SO2 to SO3 case study

Catalyst design is key to the improvement of chemical process efficiency. The required work for the development of new catalysts can be supported through the proper application of artificial intelligence to identify optimal compositions. A generic methodology for the application of machine learning to catalysis research is therefore outlined in this work. The catalytic oxidation of SO₂ was used to exemplify the first iteration of this methodology. 1784 data points from 31 published papers were compiled into a databank. The inlet SO₂ concentration ranged from 0 to 66 mol%. An artificial neural network (ANN) was trained on the databank in order to predict SO₂ conversion based on the catalyst composition and the reactor operating conditions (temperature, pressure, catalyst mass: volumetric flowrate ratio (w/v), and feed composition). The model achieved a root-mean-square error of 6.6%. A preliminary screening step identified 3:1 V-Mg/SiO₂ catalysts as exhibiting high conversion at 648 K. A multi-objective optimization was then performed on a single catalyst to identify solutions exhibiting high conversion and high productivity at 648 K while minimizing the catalyst cost. The optimal solution was predicted to be a 2.9 wt% V/0.2 wt% Mg/SiO₂ catalyst operating at a w/v of 7.49 kg-cat · s/m³ STP, achieving 100% SO₂ conversion with a material cost among the bottom third of cost values. Artificial intelligence can then be employed to extract useful knowledge from published catalytic data and orient future search for novel catalyst development.     

2-异丙基-5-甲基-2-己烯醛的合成与表征

以异戊醛为原料,在回流加热条件下进行羟醛缩合反应合成了2-异丙基-5-甲基-2-己烯醛。考察了催化剂种类和用量、相转移催化剂用量和反应时间等关键因素对反应的影响。实验结果表明,氢氧化钠作催化剂,其用量为异戊醛质量的3.0%,四丁基溴化铵作相转移催化剂,其用量为异戊醛质量的1.0%,反应3 h时,产物收率为83.3%。产品用红外光谱以及1H和13C核磁共振谱进行表征。     

阳离子交换树脂催化古龙酸甲酯的非均相动力学

以阳离子交换树脂H11为催化剂催化合成2-酮基-L-古龙酸甲酯。考察了催化剂的内外扩散、反应温度、反应物浓度配比、催化剂浓度对反应的影响,得到了最佳反应条件,反应最高产率可达到97%。还考察了催化剂的失活性,发现H11是一种理想的催化剂,连续反应4次都不影响催化效果。反应数据用Langmu ir-H inshel-wood模型拟合,通过验证反应模型符合反应原理,表面反应是关键的控速步骤,反应活化能为32 kJ/mol。     

氯化锌负载羟基磷灰石催化合成对苄基苯甲醚

以苄氯和苯甲醚为原料,氯化锌负载羟基磷灰石(ZnCl2/HAP)为催化剂,经Friedel-Crafts反应合成了对苄基苯甲醚,收率84.3%,纯度98.8%。产品经IR、1HNMR和元素分析表征。考察了苯甲醚体积、反应时间、催化剂用量及催化剂循环使用等因素对产率的影响,并得出了最适应的工艺条件:苯甲醚50mL、回流反应时间5min、催化剂0.3g(相对于0.05mol苄氯)。催化剂可循环使用4次,收率基本不变。     

SO_4~(2-)/La_2O_3-TiO_2-HZSM-5催化合成乙酸丁酯

将SO42/TiO2-HZSM-5负载镧制备了新型催化剂SO42/La2O3-TiO2-HZSM-5,以乙酸和正丁醇的酯化反应为探针,考察了不同制备条件对催化剂性能的影响。结果表明:La3+浸渍浓度为0.07mol/L,经110℃烘干后于500℃焙烧3h所得催化剂活性最好。采用正交实验法对影响酯化反应的因素进行考察,最佳实验条件为n(醇)∶n(酸)=1.5∶1,反应时间2h,催化剂用量2%(总物料),酯化率可达97.8%。且该催化剂具有良好的重复使用和再生能力。     

Kinetic and morphological study of a magnesium ethoxide‐based Ziegler–Natta catalyst for propylene polymerization

BACKGROUND: Kinetic and morphological aspects of slurry propylene polymerization using a MgCl₂‐supported Ziegler–Natta catalyst synthesized from a Mg(OEt)₂ precursor are investigated in comparison with a ball‐milled Ziegler–Natta catalyst. RESULTS: The two types of catalyst show completely different polymerization profiles: mild activation and long‐standing activity with good replication of the catalyst particles for the Mg(OEt)₂‐based catalyst, and rapid activation and deactivation with severe fragmentation of the catalyst particles for the ball‐milled catalyst. The observed differences are discussed in relation to spatial distribution of TiCl₄ on the outermost part and inside of the catalyst particles. CONCLUSION: The Mg(OEt)₂‐based Ziegler–Natta catalyst is believed to show highly stable polymerization activity and good replication because of the uniform titanium distribution all over the catalyst particles. Copyright © 2008 Society of Chemical Industry     

不规则形状A301氨合成催化剂内扩散有效因子

对于不规则形状A301氨合成催化剂,测定了其形状系数和球化的当量直径及高压下本征动力学方程,用SPSR法测定了不规则催化剂颗粒的曲折因子,根据多组分单一反应等温球形A301氨合成催化剂内反应-扩散-维模型,用正交配置法结合解非线性方程组的Broyden拟牛顿法求解了模型,获得了催化剂粒内各组分的浓度分布和催化剂的内扩散有效因子.利用所测得的高压下A301催化剂的总体速率对模型进行了检验,模型计算值和实验值吻合,表明球化模型和所得当量直径、曲折因子等模型参数可用于描述A30l催化剂内的反应-扩散过程及工程设计计算.     

L-丙交酯的合成研究

L丙-交酯产率偏低是制约聚-L-乳酸大规模应用的关键因素之一,寻找合理的催化剂是其中的关键技术。分别采用氧化锌(ZnO)、辛酸亚锡[Sn(Oct)2]、氧化锌/辛酸亚锡[ZnO/Sn(Oct)2]、三氧化二铝/辛酸亚锡[A l2O3/Sn(Oct)2]催化剂合成L-丙交酯。实验结果表明,催化剂的种类和用量对L-丙交酯的收率有显著的影响。以A l2O3/Sn(Oct)2为催化剂,用量为反应物总质量的2.03%时催化效果较好,能使L-丙交酯的收率高达70.5%。     

The oxidation of carbon monoxide at ambient temperature over mixed copper–silver oxide catalysts

Cu₂Ag₂O₃ has been prepared by a precipitation method and evaluated for ambient temperature carbon monoxide oxidation. The Cu₂Ag₂O₃ catalyst demonstrated appreciable activity and a relationship with preparation ageing time was observed. An ageing time of 4 h produced a catalyst with the highest oxidation performance. The catalyst precursor materials, prepared by drying at room temperature, displayed initial high activity, which decreased with time on line. The precursors were transformed during CO oxidation to form the mixed oxide Cu₂Ag₂O₃ as the material was dried in situ. A comparison of the catalytic activity has been made with a representative sample of a high activity hopcalite, mixed copper/manganese oxide catalyst. On the basis of CO oxidation rate data corrected for the effect of catalyst surface area the Cu₂Ag₂O₃, aged for 4 h was at least as active as the hopcalite catalyst.     

固体超强酸SO42-/TiO2-Al2O3-SnO2催化合成DBS

以固体超强酸SO4^2-／TiO2-Al2O3-SnO2为催化剂、葵二酸和正丁醇为原料合成了癸二酸二丁酯(DBS)。研究了反应时间、醇酸物质的量比、催化剂用量等对酯化率的影响。结果表明：最佳反应条件为以0.05mol葵二酸为基准，n(酸)：n(醇)=1：4，催化剂0．5g，反应时间3．5h，此时酯化率达97．5％，产品质量分数大于98％；催化剂重复使用6次后，催化活性基本不变。     

基于钒钛基SCR法废脱硝催化剂的回收利用

随着“十二五”期间国家对氮氧化物排放控制要求的进一步提高,选择性催化还原法（ SCR）烟气脱硝技术被广泛应用于燃煤电厂的烟气脱硝。本文介绍了我国目前燃煤电厂烟气脱硝催化剂的成分、失效机理及再生情况,分析了SCR法废脱硝催化剂处理的几种方式及存在的问题,提出了基于钒钛基SCR法废脱硝催化剂的资源化利用途径,实现工业固废的无害化、资源化综合利用,从而促进催化剂行业的健康可持续发展。     

Pd‐Ag/α‐Al2O3 Catalyst Deactivation in Acetylene Selective Hydrogenation Process

The selective hydrogenation of acetylene to ethylene over Pd‐Ag/α‐Al₂O₃ catalysts prepared by different impregnation/reduction methods was studied. The best catalytic performance was achieved with the sample prepared by sequential impregnation. A kinetic model based on first order in acetylene and 0.5th order in hydrogen for the main reaction and second‐order independent decay law for catalyst deactivation was used to fit the conversion time data and to obtain quantitative assessment of catalyst performances. Fair fits were observed from which the reaction and deactivation rate constants were evaluated. Coke deposition amounts showed a good correlation with catalyst deactivation rate constants, indicating that coke formation should be the main cause of catalyst deactivation.     

固体超强酸La3+-SO42-/TiO2-Fe2O3催化合成对羟基苯甲酸丁酯

以固体超强酸La3+-SO42-/TiO2-Fe2O3为催化剂合成了对羟基苯甲酸丁酯,考察了原料配比、催化剂用量、反应温度和反应时间等因素对产品收率的影响。试验结果表明:La3+-SO42-/TiO2-Fe2O3是合成对羟基苯甲酸丁酯的良好催化剂,当n(丁醇)/n(对羟基苯甲酸)=4.0,催化剂用量为对羟基苯甲酸质量的6%,反应温度120℃,反应时间4.0 h,对羟基苯甲酸丁酯的收率达到89.27%。     

Potassium‐catalyzed steam gasification of ash‐free lignite coal with CO2 capture

The purpose of this research was to study steam gasification of ash‐free coal integrated with CO₂ capture in the presence of a K₂O catalyst for enhancement of the key water‐gas shift reaction and promotion of hydrogen production. To achieve this goal, gasification experiments on ash‐free coal (AFC) were carried out at varying temperatures (600, 650, 675, 700, and 750 °C) with a sorbent‐to‐carbon (CaO/C) ratio of 2 and a catalyst (K₂O) loading of 0.2 g/g (20 weight percent (wt%)) in a fixed‐bed reactor equipped with a gas chromatography analyzer. The sorbent‐to‐carbon (CaO/C) ratio of 2 is based on dry and ash‐free basis. The CaO/C ratio and K₂O wt% were chosen to maximize hydrogen production based on our previously determined optimal values. The AFC was originally extracted from raw lignite coal using organic solvents, which allowed the sorption‐enhanced gasification to be conducted with minimal ash‐catalyst interactions. The effect of temperature on the yield and the initial reaction rate were investigated. The optimal reaction temperature of 675 °C was determined. Carbon balance and final carbon conversions were calculated based on the residue analysis. Activation energy was also calculated using intrinsic kinetics of the reaction. In this study, using AFC offered the potential advantage of operating the gasification process with catalyst recycle.