MCM-41分子筛的水热合成、改性及其应用研究进展

介绍了以水热合成法为主的介孔MCM-41分子筛的合成,简述了近几年国内外介孔MCM-41材料的改性,尤其是金属掺杂改性以及杂多酸改性等方面的最新研究,详细介绍了关于功能化的MCM-41在诸多工业反应上的应用,如在烷基化催化、酯化催化、异构化催化等反应中的应用,最后对介孔MCM-41分子筛材料的发展前景以及未来亟需解决的问题进行了展望。     

MCM-41分子筛固载羧基钯（Ⅱ）配合物催化剂的制备、表征和催化性能（Ⅰ）催化剂的制备与表征

合成了一系列新的MCM-41分子筛固载羧基钯（Ⅱ）配合物催化剂,并利用XRD、XPS、FT-IR和FT-Raman等技术对催化剂进行了表征。研究表明,MCM-41分子筛表面的Si—OH基可与三乙氧基硅烷类化合物发生作用,合成了表面羧基功能化的介孔MCM-41材料。 MCM-41分子筛在有机功能化过程中虽然其比表面积、孔容和平均孔径有所减少,但其孔结构未被破坏。MCM-41分子筛载体上的—COOH配体通过与Pd(OAc)2中OAc基的交换反应而与Pd2＋发生配位。     

MCM-41介孔分子筛合成与改性的研究进展

简要介绍了MCM-41介孔分子筛的特点,应用和改性原因.综述了MCM-41介孔分子筛的合成方法,主要包括水热合成法,室温合成法,微波合成法等,列出了每种合成方法的优缺点和合成过程中的影响因素,pH值、晶化时间、晶化温度、模板剂的种类及用量等都会对MCM-41介孔分子筛的结构和孔径产生很大影响.阐述了MCM-41介孔分子筛的改性方法,包括金属杂原子取代法,如主族金属、过渡金属、稀土金属等,有机修饰或功能化法,负载型改性法,如负载金属氧化物、无机酸、杂多酸、有机碱、金属的配合物等.最后就MCM-41介孔分子筛的应用前景做了展望.     

MCM-41介孔分子筛的合成、改性及应用研究进展

介绍了MCM-41介孔分子筛的优点,主要表现在具有较大的比表面积,孔体积与孔径和可调变等。综述了MCM-41介孔分子筛的合成方法与改性研究现状,阐述了MCM-41介孔分子筛的应用研究进展。     

MCM-41介孔分子筛的改性与应用研究

纯MCM-41介孔分子筛具有稳定的骨架结构、孔道规则排列有序、孔径分布窄等优点,但其水热稳定性较差、酸性弱、孔径不够大、难以用于大分子反应.研究人员采用扩孔改性、金属改性、杂多酸改性和其它改性等方法对MCM-41介孔分子筛进行改性,以改善其催化性能.介绍了MCM-41介孔分子筛的改性及其在石油化工过程中的应用.     

微结构单元提高介孔MCM-41分子筛水热稳定性的研究进展

综述了微结构单元提高介孔MCM-41分子筛水热稳定性的主要合成方法和研究现状,系统分析了不同微结构单元对介孔分子筛MCM-41水热稳定性的影响规律,探讨了微结构单元与介孔分子筛水热稳定性之间的关联度,阐释了微结构单元合成镶嵌结构或核壳结构的高水热稳定性介孔分子筛的机理,最后展望了高水热稳定性介孔分子筛的应用前景。     

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.     

微波技术在制备MCM-41介孔分子筛的应用

微波法合成介孔分子筛材料具有反应速率快、能耗低、产物粒度均匀等优点,具有乐观的应用前景.本文综述了微波技术在MCM-41分子筛研究领域中,介孔材料的合成、修饰改性等方面的研究进展.     

Pd-MCM-41介孔材料的合成、表征及催化性能研究

用微波辐射法合成了介孔分子筛MCM-41,采用浸渍法获得不同钯含量的Pd-MCM-41催化剂,用XRD、低温N2吸附-脱附、IR对MCM-41及组装体进行了表征;研究了Pd负载量、反应时间、反应温度等条件对葡萄糖氧化反应的影响,结果表明Pd-MCM-41能有效催化葡萄糖氧化反应。     

层状硅酸盐矿物合成MCM-41介孔分子筛的研究进展

文章分别概述了层状硅酸盐矿物和MCM-41介孔分子筛的优势,以及层状硅酸盐矿物合成MCM-41介孔分子筛的优势;综述了膨润土、高岭土、海泡石等层状硅酸盐矿物的提纯与活化方法,层状硅酸盐矿物合成MCM-41介孔分子筛的研究进展;最后就层状硅酸盐矿物合成MCM-41分子筛给出了自己的见解,提出了一些不足之处,并对其发展前景进行了展望。     

Enhanced CuCl dispersion by regulating acidity of MCM-41 for catalytic oxycarbonylation of ethanol to diethyl carbonate

CuCl supported on molecular sieves has attracted increasing attention in catalyzing oxidative carbonylation of ethanol to diethyl carbonate. Mesoporous MCM-41 has been widely used as catalyst support due to its large surface area and well defined mesoporous structure. Considering its intrinsic weak acidity, MCM-41 was modified by a simple impregnation method to incorporate Al. The incorporation of Al components resulted in the high dispersion of Cu species and the increase of acid sites without changing the mesoporous structure of MCM-41, and thus enhanceed the catalytic activity of CuCl/MCM-41for diethyl carbonate synthesis.     

Catalytic Activity of Mesoporous Silica for Synthesis of Methyl N-Phenyl Carbamate from Dimethyl Carbonate and Aniline

Mesoporous silica MCM-41, especially an Al-containing one, showed high catalytic activity for synthesis of methyl N-phenyl carbamate from dimethyl carbonate and aniline at 363-383 K. It was easily separated from the product solution, and the catalyst was able to be used repeatedly.     

MCM-41分子筛的制备及催化性能研究

用微波法合成MCM-41中孔分子筛.并采用液相沉积法制备了以MCM-41分子筛为载体负载TiO2/S2O82-的同体酸催化剂,以乙酸与异戊醇的酯化反应作为探针反应,考察了焙烧温度、焙烧时间、浸渍溶液的浓度、浸渍时间以及钛硅比等制备条件对催化剂催化活性的影响,得到了最佳的制备条件.最佳条件是:n(Ti)/n(Si)=2,...     

SO2-4/ZrO2/MCM-41催化合成柠檬酸三丁酯的研究

水热合成了介孔材料MCM-41,并以其为载体负载固体超强酸SO^2-₄/ZrO₂,通过XRD和N2吸附/脱附对制备的SO^2-₄/ZrO₂/MCM-41催化剂进行表征,认为MCM-41负载SO^2-₄/ZrO₂后,仍为长程有序的六方孔道结构。在固定床反应器中,以柠檬酸和正丁醇为原料,研究该催化剂合成柠檬酸三丁酯的活性。对反应条件进行了考察,得出最佳反应条件：温度140 ℃,空速1.0 h^-1,醇酸物质的量比为4.5。在此条件下,柠檬酸的酯化率最高可达94.5％。48 h的寿命实验结果表明,该催化剂具有较好的稳定性。     

Preparation of mesoporous MCM-41 from natural sepiolite and its catalytic activity of cracking waste polystyrene plastics

Mesoporous MCM-41 was prepared by leaching of sepiolite and sequent hydrothermal synthesis in NaOH solution with hexadecyltrimethylammonium bromide as template. Small-angle X-ray diffraction patterns, Scanning electron microscopy, transmission electron microscopy and Brunauer–Emmett–Teller were performed to characterize the resulting compounds. The results showed that the crystallinity and pore size of MCM-41 increased with increase of crystallization time, ratios of surfactant to SiO₂ and decrease of Mg content. The experimental results of catalytic cracking of polystyrene waste showed that the MCM-41 with MgO from natural sepiolite had high catalytic activity and good selectivity to monomer styrene for the catalytic cracking of polystyrene when the ratio of waste plastics to MCM-41 was 200. The side reactions yielded ethylbenzene, isopropylbenzene, isopropenylbenzene and secondary cross-linking were suppressed by basic species MgO in MCM-41.     

Cu-MCM-41催化剂的制备及在草酸酯加氢制乙二醇催化性能

采用蒸氨沉淀法制备了Cu-MCM-41分子筛催化剂,并采用BET、TEM、XRD和TPR等表征手段对该催化剂进行了表征。表征结果说明所研制催化剂具有规整有序的介孔结构并且活性组分铜得到了良好的分散。通过对该催化剂在草酸二甲酯（DMO）加氢制乙二醇反应中反应性能的研究发现,反应温度、反应压力、氢酯比和液时空速等工艺参数均对催化活性产生重要影响。结果表明,Cu-MCM-41催化剂在反应温度473 K,反应压力2.5 MPa,n(氢)∶n(酯)为80～100时表现出最佳的加氢反应性能,液时空速在2.0 h^-1时,DMO仍然可以完全转化并且乙二醇（EG）选择性达到98%以上。     

Esterification of bioplatform molecules over 12-tungstophosphoric acid anchored to MCM-41

The catalytic conversion of bio-platform molecules into desired products can be an important unit for the future biorefinery. The present contribution consists of synthesis of solid acid catalyst comprising 20 % 12-tungstophosphoric acid (TPA) and MCM-41 and its characterization by various physico-chemical techniques such as fourier transform infrared, X-ray diffraction surface area measurement (BET method), transmission electron microscopy and total acidity. The use of synthesized catalyst was explored for esterification of bio-platform molecules such as succinic acid and malonic acid with different alcohols. The catalyst shows high activity in terms of higher yields towards all diesters. The product selectivity towards the mono and diester was found to be the same for TPA alone and supported system, TPA₂/MCM-41, that also confirms the uniform distribution of the TPA on MCM-41. The excellent catalytic performance is attributed to the large surface area and pore diameter of the mesoporous support, MCM-41 as well as the Bronsted acid strength of TPA, as active sites. The catalyst shows the potential of being used as a recyclable catalytic material after simple regeneration without significant loss in activity.     

One-step synthesis of bimetallic Pt-Pd/MCM-41 mesoporous materials with superior catalytic performance for toluene oxidation

The catalytic performances of Pt-Pd/MCM-41 bimetallic catalysts prepared by one-step synthesis method were investigated for total toluene oxidation in this paper. The experimental results demonstrated that Pt-Pd/MCM-41 was of superior catalytic activity comparing to the monometallic Pt/MCM-41 or Pd/MCM-41 catalysts with the same metallic content, yielding an almost 100% conversion at 180 °C. The following characterization results indicated that the bimetallic catalyst possessed a higher surface Pt(0) content and smaller doped metal size owing to the synergistic effect of the two noble metals, resulting in the improvement of oxygen adsorption capacity and the reducibility.     

改性中孔分子筛MCM-41催化合成丙酸香叶酯

用H2SO4对中孔分子筛MCM（mobile crystalline material）-41进行改性,得到SO42–修饰的中孔分子筛SO42–/MCM-41。通过X射线衍射、红外光谱、NH3程序升温脱附和N2吸附–脱附等方法对所合成样品进行表征。用SO42–/MCM-41催化合成丙酸香叶酯,考察了催化剂处理方法、催化剂用量、催化剂再生对香叶醇酯化反应结果的影响,并比较了H2SO4、MCM-41和SO42–/MCM-41这3种催化剂对合成丙酸香叶酯的催化性能。结果表明：用浓度为0.50mol/L的硫酸浸泡MCM-41中孔分子筛1h,再于450℃焙烧3.0h,能得到良好长程有序性和结晶度的中孔分子筛SO42–/MCM-41,用其催化合成丙酸香叶酯,香叶醇的转化率最高可达88.82%,丙酸香叶酯的选择性为85.20%;H2SO4改性对MCM-41中孔分子筛结构影响不明显,但可提高其酸性。