介孔载体负载的碱性离子液体催化合成碳酸丙烯酯

采用后嫁接法将碱性离子液体1-丁基-3-甲基咪唑的氢氧化物(［Bmim］OH)分别负载到介孔硅胶、MCM-41分子筛和SBA-15分子筛上制备了非均相负载型离子液体,采用傅立叶变换红外光谱、N2吸附-脱附、元素分析和热重分析等手段对其表征,发现离子液体以共价键嫁接到硅胶上,且有较好的热稳定性。在无溶剂和温和的条件下,以非均相负载型离子液体为催化剂,研究了环氧丙烷与CO2环加成合成碳酸丙烯酯的反应,结果表明,3种非均相负载型离子液体均具有较好的催化性能,其中,［Bmim］OH/SiO₂的催化性能最好,在最优条件下,环氧丙烷转化率可达99.1%,反应后催化剂经过滤即可分离回收利用,多次使用仍保持较高的反应活性。     

Alkylation of 1-Dodecene with Benzene over H3PW12O40 Supported on Mesoporous Silica SBA-15

The SBA-15 supported 12-phosphotungstic acid catalysts were prepared and measured in the alkylation of benzene with 1-dodecene at the atmospheric batch reactor. It is found that the catalysts exhibit much higher catalytic activity, selectivity and stability than HY zeolite in this reaction at the reaction temperature of 80 °C, with the 1-dodecene conversion of nearly 90%, 2-phenyldodecane selectivity of nearly 40%, and monoalkylbenzene selectivity of 100%.     

LB-16有机硅杂化分子筛催化剂的制备及其在长链烷基苯合成中的应用

长链烷基苯(LAB)是制备合成洗涤剂烷基苯磺酸钠的主要原料,传统上LAB采用无机液体酸(HF)为催化剂将苯和长链烯烃烷基化而制得。在LAB的诸多异构体中,2-LAB因其更高的溶解性和可降解性而更受欢迎。使用低温成胶的策略,以水热合成法合成LB-16有机硅杂化分子筛催化剂,并考察其在LAB合成中的催化性能。结果表明,在反应温度190℃、空速0.2 h-1、苯烯物质的量比15∶1条件下,经过1 000 h催化试验,1-十二烯转化率大于99%,2-LAB选择性51%。LB-16有机硅杂化分子筛催化剂对苯与1-十二烯合成反应具有较好的催化活性和稳定性,同时对2-LAB具有较高的选择性,具有工业化应用前景。     

碳基对甲苯磺酸催化剂在烷基化反应中的研究

利用可溶性淀粉和对甲苯磺酸混合物的部分炭化制备了碳基对甲苯磺酸催化剂,研究了该催化剂在苯与1-十二烯烷基化反应中的催化性能,考察了催化剂的处理温度、苯烯摩尔比、反应时间、催化剂的质量分数等因素对烷基化反应的影响以及催化剂的再生性能。结果表明：该催化剂在苯与1-十二烯烷基化反应中具有较好的催化活性和可再生性。在催化剂的处理温度为200℃、苯与1-十二烯的摩尔比为8,催化剂的质量分数5％和回流反应2．0h的条件下,1-十二烯的转化率为94．3％,LAB的选择性为95．0％,2-LAB的选择性为75．0％。     

磷化物催化剂体系下二苯并噻吩加氢反应网络研究

为考察二苯并噻吩在磷化物体系下催化加氢的反应网络,以分子筛SBA-15为空白载体,利用等体积浸渍制取了一系列磷化物催化剂,Ni/P摩尔比为1.25,对不同Ni金属担载量的磷化物催化剂的性质进行了分析。采用含有1%二苯并噻吩的模型化合物为原料进行加氢脱硫试验,利用20 m L连续固定床加氢精制装置对制备的磷化物催化剂进行了活性评价。结果表明,相对于商业催化剂,低温和磷化物催化剂体系下二苯并噻吩具有更高的转化率,280℃转化率可达80%以上;碱性氮化物喹啉的存在抑制了二苯并噻吩加氢反应,转化率在320℃时由接近100%降至70%左右,此条件下,产物中联苯以及环己烷基苯的选择性随温度变化不大,二苯并噻吩大部分通过直接脱硫路径进行转化。评价结果显示,磷化物催化剂具有更高的氢解活性和更好的直接加氢脱硫效果。     

不同铝源对SBA-15分子筛改性影响

为比较不同铝源对SBA-15分子筛改性的影响,以正硅酸乙酯为硅源,分别用异丙醇铝、氯化铝和硝酸铝对SBA-15分子筛进行改性, 运用XRD、N2等温吸附-脱附、SEM、 TEM和气相色谱对样品进行表征。将3种不同铝源改性SBA-15分子筛与USY分子筛复合制备加氢裂化催化剂,在固定床微型反应装置进行加氢裂化性能评价,结果表明,异丙醇铝在酸性条件下水解生成的Al(OH)^-₄更容易进入SiO₂骨架中,生成的产物异丙醇不影响铝离子的掺杂,由于异丙醇铝与正硅酸乙酯的水解速率一致,改性后所得材料孔分布更均一,规整性更高。将异丙醇铝对SBA-15分子筛改性后,与USY制备的复合分子筛催化剂用于正十二烷加氢裂化反应,选择性和转化率优于氯化铝和硝酸铝改性的分子筛。     

MPc/SBA-15的模拟酶催化研究

采用浸渍法将两种金属酞菁-α-八丁氧基酞菁钴（CoPc）和α-八丁氧基酞菁铜（CuPc）负载到介孔分子筛SBA-15上,制备CoPc/SBA-15和CuPc/SBA-15两种催化剂,通过紫外-可见光谱、红外光谱、N₂吸附对其结构进行表征,研究pH值、催化剂类型、催化剂用量、底物浓度以及反应温度对催化效果的影响。实验结果表明：在相同的催化条件下,两种催化剂对巯基乙醇（ME）均表现出良好的催化性能,且CuPc/SBA-15的催化氧化性能优于CoPc/SBA-15,符合酶催化氧化反应的特征,遵循米氏方程动力学规律,其米氏常数和最大反应速率分别为27.23 mmol/L和1.72×10^-4 L/min,该催化反应属于吸热反应,其活化能E_a为29.17 kJ/mol。     

Benzylation of benzene and other aromatics by benzyl chloride over mesoporous AlSBA-15 catalysts

Aluminum-containing mesoporous molecular sieves AlSBA-15 with different n_Si/n_Al ratios and AlMCM-41 have been synthesized hydrothermally and characterized in detail by physicochemical methods, viz. XRD, N₂ adsorption and ²⁷Al NMR spectroscopy. The low angle XRD and N₂ adsorption measurements reveal that the structural order of SBA-15 was retained after the incorporation of Al. The increase of the unit cell parameter with increasing aluminum content and ²⁷Al MAS NMR spectroscopy confirm the incorporation of aluminum in the framework. Benzylation of benzene and substituted benzenes reaction employing benzyl chloride as the alkylating agent over AlSBA-15 and AlMCM-41 have been investigated. The influence of various reaction parameters such as reaction temperature, reactant feed ratio and catalyst amount affecting the activity and selectivity of AlSBA-15, have been studied. Among the mesoporous catalysts studied, AlSBA-15(45), where the number in parentheses indicates the molar n_Si/n_Al ratio, shows both high conversion and high selectivity for the benzylation of benzene. The activity of this catalyst for the benzylation of different aromatic compounds is in the following order: benzene > toluene > p-xylene > mesitylene > anisole. Kinetics of the benzene benzylation over different catalysts have also been investigated.     

Hoveyda-Grubbs type metathesis catalyst immobilized on mesoporous molecular sieves—The influence of pore size on the catalyst activity

New hybrid olefin metathesis catalysts were prepared by immobilization of Hoveyda-Grubbs type catalyst (commercially available as Zhan catalyst-1B) on the surface of mesoporous molecular sieves differing in pore size and architecture (MCM-41, MCM-48, and SBA-15) and conventional silica for a comparison. The activity of these catalysts was tested in RCM of (−)-β-citronellene, metathesis of 1-decene, ADMET of 1,9-decadiene, and in ROMP of cyclooctene and was found to increase significantly with the increasing pore size of the supports used. In all reactions, the activity of hybrid catalysts based on mesoporous molecular sieves was higher than that of catalyst using conventional silica as a support. In ROMP of cyclooctene, high molecular weight polymer (M_w = 300,000) in high yield (70-80%) was obtained with catalysts based on mesoporous supports, however, only 40% polymer yield was obtained using catalyst based on conventional silica.     

[Bmim]Cl-xAlCl_3催化合成十二烷基苯

采用AlCl3和[Bmim]Cl不同摩尔比的[Bmim]C1-xA1C13离子液体为催化剂,研究了不同条件下1-十二烯与苯的烷基化反应。实验结果表明,以A1Cl3和[Bmim]Cl的摩尔比为2.0([Bmim]Cl-2A1C13)的离子液体为催化剂,在反应温度25℃、反应时间30 min,苯、烯及离子液体的摩尔比为5︰1︰0.03的条件下,正十二烯的转化率可达98.32%,2-LAB的选择性可达36.76%。离子液体和产物可形成易于分离的双液相,简化了催化剂与产物的分离操作。     

含Ni介孔分子筛的合成及其对苯加氢催化性能

采用水热法合成出不含镍和含镍的硅基介孔分子筛.利用XRD、FT-IR、TPR、TEM和比表面孔径测定等手段对样品进行了表征.结果表明：合成出有序性好的介孔分子筛（MCM-41）,550 ℃焙烧可以将模板剂有效去除,所合成介孔分子筛负载Pt后介孔有序性降低,但是介孔结构仍然存在.苯催化加氢反应研究表明：不含Ni的介孔分子筛不具有加氢活性,当将其负载Pt后具有苯加氢催化活性;含Ni介孔分子筛本身具有苯加氢活性,含Ni介孔分子筛负载Pt后苯加氢催化活性有较大的提高,所有样品的环己烷选择性都接近100 %,说明含Ni介孔分子筛可以直接作为苯加氢反应的催化剂或作为苯加氢催化剂良好的载体.     

Preparation of Mesoporous Catalyst Supported on Silica with Finely Dispersed Ni Particles

A novel nickel catalyst supported on SBA-15 type mesoporous silica was synthesized by the grafting of N-(trimethoxysilylpropyl)ethylene diamine triacetic acid salt (EDTA) onto the surface of SBA-15 and followed by adsorption of nickel ions and calcinations (Ni-E-SBA). The catalysts prepared were characterized using XRD, TEM, TED, SAXS and N₂ adsorption/desorption measurements. While nickel particles loaded on catalysts prepared by the wet impregnation method were found to be aggregated on the outer wall of the supports, nickel particles were finely dispersed on the surface of the mesopores in the Ni-E-SBA catalyst. The catalytic performances of the prepared catalysts were evaluated using the hydrodechlorination (HDC) of 1,1,2-trichloroethane (TCEa) as a model reaction. Results showed that the Ni-E-SBA catalyst had the highest activities of the catalysts examined under the given conditions.     

Vanadium, niobium and tantalum modified mesoporous molecular sieves as catalysts for propene epoxidation

SBA-3 mesoporous molecular sieves doped with transition metal ions (Fe, V, Nb and Ta) have been applied for selective oxidation of propene towards propylene oxide in the presence of N₂O as an oxidant. The kind and amount of applied modifiers significantly affected the catalytic activity. V/SBA-3 was found to be the most active among the catalyst under study. In spite of relatively high selectivity towards propylene oxide (reaching up to 23%), the main oxidation product was still propionaldehyde. Surprisingly, CO_x was not formed over V, Nb and Ta modified SBA-3 catalysts. Additional modification of V containing samples (V/SBA-3) with iron complexes resulted in the further increase in the catalysts activity for epoxidation reaction. A PO selectivity of about 20% could be achieved at a propylene conversion of 17% over mixed Fe/V/SBA-3 catalytic system.     

钒基MSU-1催化剂上二氧化碳氧化异丁烷脱氢反应条件的优化研究

以介孔材料MSU-1为载体,不同金属氧化物为活性组分,分别制备负载型催化剂并研究其在CO<,2>气氛中异丁烷脱氢的催化活性.结果证明VOx/MSU-1催化剂有最好的异丁烷氧化脱氢催化活性.基于此,对影响CO<,2>氧化异丁烷脱氢的温度、空速和氧烷比等工艺条件进行了考察,结果显示,当温度为853 K,空速为7200 mL...     

Catalytic performance of various mesoporous silicas modified with copper or iron oxides introduced by different ways in the selective reduction of NO by ammonia

Mesoporous silicas (MCM-48, SBA-15, MCF), reflecting various porous structures, were modified with copper and iron oxides by two different methods. For a first series of the samples the molecular designed dispersion (MDD) method using acetylacetonate complexes of copper and iron was applied for the deposition of transition metal oxides on the silica supports. A second series of the catalysts was obtained by the incipient impregnation technique using aqueous solutions of the suitable metal nitrates. The modified materials were characterized with respect to the texture (BET), composition (electron microprobe analysis), coordination of the transition metals (UV–vis–DRS) and surface acidity (NH₃-TPD, FTIR). The mesoporous silica supports modified with transition metal oxides were tested as catalysts of the selective reduction of NO with ammonia. The catalytic performance of the studied samples depended on the method used for the deposition of transition metal oxide as well as the kind of mesoporous silica used as a catalytic support. In general, the Cu-containing mesoporous samples effectively operated at lower temperatures than silicas modified with iron. The samples obtained by the MDD method have been found to be more active and selective compared to the analogous samples prepared by the impregnation technique. An introduction of water vapor into the reaction mixture only slightly decreased the NO conversion and selectivity towards N₂ over the MCF mesoporous silica modified with copper or iron oxide.     

Direct synthesis and catalytic performance of ultralarge pore GaSBA-15 mesoporous molecular sieves with high gallium content

Mesoporous GaSBA-15 molecular sieves with different n_Si/n_Ga ratios have been directly synthesized using Pluronic 123 triblock polymer as a structure-directing agent by pH-adjusting method. The mesoporous materials have been characterized using ICP-AES, XRD, N₂ adsorption, ⁷¹Ga-MAS NMR, SEM and TEM. ICP-AES studies show a high amount of gallium incorporation on the silica pore walls. The structural and textural properties of calcined GaSBA-15 are characterized by XRD and N₂ adsorption. ⁷¹Ga MAS NMR results demonstrate that a high amount of tetrahedral-gallium could be substituted for Si in the framework of SBA-15. TEM and FE-SEM images show the uniform pore diameter and rope-like hexagonal mesoporous structure of GaSBA-15. These GaSBA-15 materials have been used as catalysts for vapour-phase t-butylation of 1,2-dihydroxybenzene (DHB) for selective synthesis of 4-t-butylcatechol (4-TBC) under different reaction conditions. GaSBA-15(10) gave the highest 93.2% conversion of DHB and 95.7% selectivity of 4-TBC as compared with other GaSBA-15 catalysts.     

Benzene selective hydrogenation over supported Ni (nano-) particles catalysts: Catalytic and kinetics studies

This report aims to reduce the benzene in a mixture of benzene and toluene as a model reaction using catalytic hydrogenation. In this research, we developed a series of catalysts with different supports such as Ni/HMS, Ni/HZSM-5, Ni/HZSM5-HMS, Ni/Al_2O_3 and Ni/SiO_2. Kinetic of this reaction was investigated under various hydrogen and benzene pressures. For more study, two kinetic models have also been selected and tested to describe the kinetics for this reaction. Both used models, the power law and Langmuir–Hinshelwood, provided a good fit toward the experimental data and allowed to determine the kinetic parameters. Among these catalysts, Ni/Al_2O_3 showed the maximum benzene conversion(99.19%) at 130 °C for benzene hydrogenation. The lowest toluene conversion was observed for Ni/SiO_2. Furthermore, this catalyst presented high selectivity to benzene(75.26%)at 130 °C. The catalytic performance(activity, selectivity and stability) and kinetics evaluations were shown that the Ni/SiO_2 is an effective catalyst to hydrogenate benzene. It seems that the surface properties particularly pore size are effective parameter compared to other factors such as acidity and metal dispersion in this process.     

Low-temperature ozone decomposition,CO and iso-propanol combustion on silver supported MCM-41 and silica

Silver modified (5 and 2 wt% loading) mesoporous molecular sieves (H-MCM-41, with Si/Al ratio 20, 40 and 50) and silica were synthesized by incipient wetness impregnation and ion-exchange methods. The obtained catalysts were characterized by different techniques (ICP, XRD, XRF, SEM, FTIR and nitrogen physisorption) and they were tested in heterogeneous catalytic decomposition of ozone and oxidation reactions involving ozone at ambient temperature. All the mesoporous catalysts have very high catalytic activities towards ozone decomposition at room temperature and they do not reveal any deactivation with the time on stream. The activities of the catalysts are enhanced upon increasing the amount of supported silver, decreasing the support acidity and modifying the catalyst with some additional metal having basic properties, such as Ce. The most active catalyst in the reaction of ozone decomposition—5Ag-H-MCM-41-50, shows also high activity at ambient temperature in the oxidation of CO and iso-propanol with ozone.     

Bifunctional Materials for the Catalytic Conversion of Cellulose into Soluble Renewable Biorefinery Feedstocks

The combination of Br?nsted acidity with metallic functionality in a mesoporous catalyst offers a potential pathway for the conversion of cellulose into sugar alcohols that may be used as a sustainable source of renewable biorefinery feedstock. Supported Ru catalysts were prepared by evaporative deposition on various ordered mesoporous silicas (SBA-15) with different functionalities and characterized using multiple experimental techniques. The catalytic performance of the supported Ru catalysts was compared to that of the corresponding supports and of Ru/C. We studied the effects of functional group loading, reaction time and temperature on the activity and products yield of the bifunctional catalysts by monitoring the cellulose conversion and the production of sugars and sugar alcohols in a high-pressure batch reactor. Sorbitol is the main product obtained by the hydrolysis of cellulose to glucose followed by the corresponding reduction. Secondary products include sugars, ethylene glycol and glycerol. The activity of mesoporous silica catalysts increases with an increase in acid loading and the addition of Ru allows control of the selectivity towards sugar alcohols. Ruthenium supported on arenesulfonic acid-functionalized mesoporous silica (Ru/SBA-15S) displays the best catalytic performance. Ru/SBA-15S is more hydrothermally stable than SBA-15, but loses a significant fraction of its surface area, crystallinity, acidity and activity after prolonged exposure to water at 483?K.     

SBA-15固载磷钨酸催化剂的制备及催化合成叔丁基苯酚

以不同硅烷偶联剂改性的介孔分子筛SBA-15为载体、PW_(12)为催化剂,通过对SBA-15表面共价及非共价修饰制备磷钨酸@介孔分子筛/硅烷偶联剂复合催化剂PW_(12)@SBA-15/YSiX_3(YSiX_3=Apts、Atapts、Papts);并利用FT-IR、XRD、TEM、N_2吸附-脱附对其组成、结构及形貌进行表征。以改性SBA-15分子筛固载磷钨酸催化剂催化合成叔丁基苯酚为研究对象,考察不同硅烷偶联剂、反应温度、苯酚与叔丁醇物质的量比对催化合成叔丁基苯酚的影响,并获得合成叔丁基苯酚的最佳工艺条件,即反应温度145℃、n(苯酚)∶n(叔丁醇)=1∶2.5、重时空速2.2 h~(-1),该最佳反应条件下,PW_(12)@SBA-15/Apts催化剂催化合成叔丁基苯酚的催化活性最高,苯酚转化率为98.3%,2,4-二叔丁基苯酚选择性为57.3%.