邻硝基苯胺催化加氢合成邻苯二胺

以Ni/SiO2作催化剂,研究了反应温度、反应压力、溶剂种类等因素对产品收率的影响,得到的优化反应条件为:反应温度为57.5℃,反应压力为0.85 MPa,溶剂种类为甲醇,邻苯二胺收率稳定在95%以上,质量分数大于98%。     

Hydrogenation of Citral Over a Polymer Fibre Catalyst

A polymer-supported Pd catalyst was investigated in hydrogenation of citral (3,7-dimethyl-2,6-octadienal), which is a stereoisomer with an isolated and a conjugated double bond as well as a carbonyl group. The catalyst was a fibrous polymer-supported catalyst modified with functional groups and immobilized metals. A comparison of the polymer-supported catalyst with conventional catalysts was made.     

2-戊基蒽醌氢化本征动力学研究

采用商品化的Pd/Al2O3催化剂,在温度为313.15～343.15 K、压力为0.1～0.2 Mpa的条件下,研究了2-戊基蒽醌加氢本征动力学.反应在体积比为3:1的三甲苯/磷酸三辛酯混合溶剂中进行.采用幂指型方程表达加氢反应速率,并用多元线性回归分析对测得的动力学数据进行处理,得到了方程中的参数.结果表明,2-戊基蒽醌加氢反应对2-戊基蒽醌浓度为零级;对氢气分压为0.48级,反应活化能为15663 J·mol-1.     

2-乙基蒽醌加氢用新型钯催化剂研究进展

高活性、高选择性催化剂是解决蒽醌法生产过氧化氢过程中瓶颈问题的根本途径。评述近年来新型蒽醌加氢用钯催化剂研究中载体改性、新型载体(包括高分子载体和纳米纤维状氧化铝载体)、助催化剂及新制备技术等方面的最新进展,指出通过载体改性可提高现有催化剂的活性和选择性,而助催化组分和新催化剂制备工艺应是今后蒽醌加氢催化剂研究的重点方向。     

溶胶-凝胶法负载型催化剂上糠醛加氢制备2-甲基呋喃

采用溶胶-凝胶法制备负载型Cu-Cr/SiO2催化剂,进行糠醛气相加氢合成2-甲基呋喃。在无梯度反应器中考察了Cu/Cr摩尔比、温度、氢醛摩尔比对催化加氢性能的影响。并通过X射线衍射探讨了催化剂的活性中心成分。     

球形Pd催化剂应用于对氯硝基苯催化加氢

在聚乙二醇、环己胺和水组成的W/O乳状液体系中,用BH4-还原Pd2+制得了球形纳米Pd催化剂,并用XRD、XPS、TEM等方法表征了催化剂的结构、表面电子态和形貌等。通过催化对氯硝基苯加氢制备对氯苯胺来评价其催化性能。结果表明,该催化剂具备较高的催化活性和选择性,对氯硝基苯转化率达到100%,对氯苯胺的选择性达到99%以上,催化剂稳定性较好可以套用6次以上。     

缚酸剂对Raney Ni催化氢解TPD制1,3-丙二醇的影响

甘油的间接氢解是新近发展的制备1,3-丙二醇的方法.研究发现甘油的间接氢解中间体TPD(2-对甲苯磺酰氧基-1,3-丙二醇)加氢过程产生的对甲苯磺酸腐蚀催化剂,导致催化剂无法重复利用.为了避免催化剂被腐蚀,选用几种缚酸剂,研究了缚酸剂对TPD加氢反应的影响,通过单因素实验考察了温度、压力和催化剂(Raney Ni)用量对反应的影响,并对反应机理作了讨论.结果表明:三乙胺作为缚酸剂时较优的反应条件为:温度100℃,压力4 MPa,催化剂用量2.0 g(TPD质量的57%),在此反应条件下,TPD转化率为89.1%,1,3-丙二醇的选择性为33.7%.催化剂重复实验结果表明加入缚酸剂能在一定程度上保护催化剂.     

苯加氢催化反应动力学研究

文章采用溶胶-凝胶法制备NiO-MoO3/Al2O3-TiO2催化剂,研究基于该催化剂苯加氢生成环己烷的反应。利用实验数据对几种可能的动力学模型进行参数估值,得到该反应的动力学模型。     

松香低压催化加氢反应的研究

采用 FYX-2 G型高压搅拌釜 ,在温度 1 60°C、压力 1 .0 MPa条件下 ,测定了松香催化加氢转化率与 Pd/ C催化剂含水量的关系 ,可见加氢反应速度随催化剂含水量的减少而增加。考察了搅拌器类型、搅拌转速对高压釜持气量及枞酸转化率的影响 ,认识到松香催化加氢是外扩散控制的反应 ,当搅拌转速达 60 0 r/ min时 ,基本上能消除外扩散的影响。比较了 Raney-镍与 Pd/ C催化剂对松香催化加氢的活性 ,实验表明在低氢压 1 .0 MPa下 ,只有 Pd/ C催化剂才能制备出合格的氢化松香产品     

助剂对Ni/SiO2催化剂1,4-丁炔二醇加氢性能的影响

通过分步浸渍法在Ni/SiO 2催化剂中分别引入Zn、Cu、La、Mo、Co金属助剂,结合N 2物理吸附-脱附、XRD、H 2-TPR和NH 3-TPD等表征手段研究金属助剂对1,4-丁炔二醇加氢性能的影响。结果发现,Mo的引入使Ni/SiO 2催化剂的初始活性大幅增加,但反应2 h后活性下降,归因于催化剂表面酸中心使催化剂积炭失活;引入Cu、La及Co后的催化剂活性较低,推测是由于催化剂表面产生强吸附氢物种,不利于1,4-丁炔二醇加氢反应进行;与其他样品相比,Zn的引入使催化剂保持了Ni/SiO 2催化剂高的1,4-丁炔二醇加氢活性,同时可有效降低产物中2-羟基四氢呋喃副产物含量,提高目标产物1,4-丁二醇收率。     

Hydrogenation of m‐dinitrobenzene to m‐phenylenediamine over La2O3‐promoted Ni/SiO2 catalysts

BACKGROUND: Liquid‐phase catalytic hydrogenation of m‐dinitrobenzene is an environmentally friendly routine for m‐phenylenediamine production. The key to increasing product yield is to develop catalysts with high catalytic performance. In this work, La₂O₃‐modified Ni/SiO₂ catalysts were prepared and applied to the hydrogenation of m‐dinitrobenzene to m‐phenylenediamine. The effect of La₂O₃ loading on the properties of Ni/SiO₂ was investigated. The reaction kinetic study was performed in ethanol over Ni/3%La₂O₃–SiO₂ catalyst, in order to clarify the reaction mechanism of m‐dinitrobenzene hydrogenation. RESULTS: It was found that the activity of the silica supported nickel catalysts is obviously influenced by La₂O₃ loading. Ni/3%La₂O₃–SiO₂ catalyst exhibits high activity owing to its well dispersed nickel species, with conversion of m‐dinitrobenzene and yield of m‐phenylenediamine up to 97.1% and 94%, respectively. The results also show that Ni/3%La₂O₃–SiO₂ catalyst can be reused at least six times without significant loss of activity. CONCLUSION: La₂O₃ shows strong promotion of the effect of Ni/SiO₂ catalyst for liquid‐phase hydrogenation of m‐dinitrobenzene. La₂O₃ loading can affect the properties of Ni/SiO₂ catalyst. Based on the study of m‐dinitrobenzene hydrogenation kinetics over Ni/3%La₂O₃–SiO₂ catalyst, a possible reaction mechanism is proposed. Copyright © 2009 Society of Chemical Industry     

Pd/Al2O3液相选择加氢催化剂抗硫性能研究

研究了助剂对Pd/Al2O3催化剂裂化汽油液相选择加氢活性及其抗硫性能的影响。着重探讨了Co助剂的作用规律。结果表明，助剂对Pd/Al2O3催化剂的加氢活性有不同影响，其中加入Ag、Cu和Co助剂时，可以提高催化剂加氢活性，而Co助剂的提高最为明显，通过对催化剂进行XPS和反应后催化剂硫含量的分析，表明Co助剂改善Pd/Al2O3催化剂液相加氢活性的作用有两方面，一是与Pd金属产生电子相互作用，改变其电子状态，减弱对硫化物的吸附；二是Co具有吸硫作用，使部分硫化物吸附在助剂Co上，从而减少了在活性中心Pd上的吸附，导致Pd－Co/Al2O3催化剂具有良好的液相选择加氢活性。     

新型镍催化剂在苯加氢中的应用研究

采用溶胶-凝胶法制备新型镍催化剂。采用微型反应装置,在反应压力为0.78MPa,氢苯摩尔比为6.5∶1,反应温度358.15~633.15K的实验条件下,研究了在NiO-MoO3/Al2O3-TiO2催化剂上苯加氢生成环己烷的反应。结果表明,在383.15~513.15K的温度范围内苯的转化率为100%,反应所得环己烷的纯度超过99.8%。     

Hydrogenation of CO2 to formic acid on supported ruthenium catalysts

We report on the preparation and application of novel heterogeneous supported ruthenium catalysts. The catalysts are active in the synthesis of formic acid from the hydrogenation of carbon dioxide and are characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction analysis and transmission electron microscopy. Abundant hydroxyl groups, which interact with the ruthenium components, play an important role in the catalytic reactions. Highly dispersed ruthenium hydroxide species enhance the hydrogenation of CO₂, while crystalline RuO₂ species, which are formed from the relatively high ruthenium content or the pH of the solution during preparation of the catalyst, restrict the production of formic acid. Optimal activity of ruthenium hydroxide as a catalyst for the hydrogenation of CO₂ to formic acid is achieved over a γ-Al₂O₃ supported 2.0 wt% ruthenium catalyst, which is prepared in a solution of pH 12.8 with NH₃·H₂O as a titration solvent. A possible hydrogenation mechanism for the hydroxide ruthenium catalyst is proposed.     

Ni-La/SiO2催化剂的制备、表征及其对大豆油加氢的催化性能研究

以硅酸钠为原料用化学沉淀法制备了SiO2,用浸渍法制备了Ni-La/SiO2催化剂前体,然后用H2气还原得到了Ni-La/SiO2催化剂。分别用XRD、SEM和TEM、N2吸附—脱附等技术对载体和催化剂进行了表征,结果表明:掺杂镧可以促进镍活性中心的形成以及有效防止Ni颗粒的团聚。考察了不同Ni/La比的催化剂对大豆油非选择性加氢的催化性能,优化了大豆油加氢条件,大豆油的碘值可由130降低至1.6。     

Long-Chain-Amine Metal Complexes as Hydrogenation Catalysts. Heterogenisation on Activated Carbon

The catalytic activity of [PdCl₂(NH₂(CH₂)₁₂CH₃)₂] (named [Pd(TDA)]) and [RhCl(NH₂(CH₂)₁₂CH₃)₃] (named [Rh(TDA)]) complexes for the hydrogenation of cyclohexene has been analysed both in homogeneous phase and heterogenised on activated carbon. The [Rh(TDA)] complex has been found to be more active than the [Pd(TDA)], both homogeneous and heterogenised. Experimental and modelled results indicate that these complexes follow a similar reaction mechanism, but with different rates. A clear positive effect of the carbon support has been found in the case of the complex [Rh(TDA)], which has been related to the anchorage of the aliphatic chains of the amine ligands on the activated carbon pores. Experiments in consecutive catalytic runs show that the heterogenised complexes can be used several times giving an acceptable conversion level.     

助剂对Ni/Al2O3催化剂在石油树脂加氢过程中抗硫性能的影响

考察了助剂Mg、Fe和Cu的加入对抑制Ni/Al2O3催化剂中Ni晶粒的增长及加入助剂的催化剂在石油树脂加氢中抗硫性能的影响,结果表明,加入少量助剂能够抑制Ni/Al2O3催化剂中Ni晶粒的长大,同时助剂的加入也有助于催化剂加氢性能的提高,但助剂的加入量也影响催化剂的加氢性能,应根据催化剂性能适当加入剂的量。     

非晶态镍合金催化剂加氢合成3，4-二氯苯胺

以3,4-二氯硝基苯催化加氢合成3,4-二氯苯胺。比较了RaneyNi、非晶态镍合金、Pd／C等3种催化剂,采用非晶态镍合金作加氢催化剂,转化率和选择性大于99％,脱氯率0．1％,催化剂寿命长,套用15批活性不下降,产品3,4-二氯苯胺含量〉99％。     

催化加氢法合成邻苯二胺

采用ＲａｎｅｙＮｉ催化剂,在甲醇或乙醇溶剂中,温度７０～８０℃,氢压１．５ＭＰａ,邻硝基苯胺催化加氢制备邻苯二胺。加氢转化率达９８．２％,邻苯二胺精制总收率在８２％左右,纯度达９９．５％以上。气相色谱、红外等对产物进行了定量、定性分析。