双杂原子Ti-V-β沸石的合成、表征及催化性能研究

以白炭黑(二氧化硅)为硅源、四乙基氢氧化铵为模板剂、硫酸钛为钛源、偏钒酸铵为钒源、氟化钠为矿化剂,采用水热法合成了Ti-V-β沸石。探讨了合成条件对Ti-V-β沸石形成的影响。运用XRD、IR、UV-Vis固体漫反射光谱、TG/DTA、SEM+EDS和ICP等测试技术对样品进行了表征并测定了样品中Ti和V的含量。结果表明,按下列化学组成配制初始反应混合物：n(SiO₂)∶n(V₂O₅)∶n(TiO₂)∶n[(TEA)₂O]∶n(H₂O)∶n(NaF)=60∶(0.05～1.2)∶(0.1～2.4)∶(12～18)∶(450～720)∶(4～14),可制备出Ti-V-β沸石,Ti和V原子进入了沸石骨架。对样品在以H₂O₂为氧化剂氧化苯乙烯反应中的催化活性作了初步考察,结果表明,Ti-V-β沸石具有很高的催化活性,在下列反应条件下：v(H₂O₂)/v(ph CH=CH₂)=2.6,V(acetone)/v(phCH=CH₂)=10,m(cat)/v(phCH=CH₂)=0.003 g·mL^-1,T=80 ℃,t=6 h,苯乙烯的转化率98.16%。产品的选择性为：苯甲醛68.15%,苯乙醛23.35%,苯乙酮6.61%。     

MFI沸石纳米片及b轴取向MFI沸石薄膜的制备

我们通过自下而上（bottom-up）的方法制备了高宽深比、高结晶度的b轴方向上超薄的MFI沸石纳米片,为制备b轴取向MFI沸石薄膜提供了基础。采用滑动涂覆法（slip coating method）在玻璃片载体上制备了厚度约为100 nm的b轴取向MFI纳米片晶种层。采用无模板剂二次生长法,抑制晶种层面外孪晶生长,实现了晶种层的面内外延生长。在合成体系的n_SiO2：n_Na2O：n_{C2 H5 OH}：n_{H2 O}=1：0.03：1.3：0.89、晶化时间48 h、晶化温度180℃时,制备了厚度约为200 nm的连续致密的b轴取向MFI沸石膜,与基于四丙基氢氧化铵（TPAOH）的常规合成溶液水热二次生长制备的MFI沸石膜相比,厚度降低了90%,并且保持了晶种层的b轴取向性。     

Cu-β沸石的合成、表征及催化性能

采用水热合成法在SiO₂-CuO-(TEA)₂O-H₂O-NH₄F体系中合成了Cu-β沸石,运用X射线衍射、红外光谱、紫外-可见固体漫反射光谱、热重-差热分析、扫描电镜和等离子体发射光谱仪等对样品进行了表征,并探讨了影响Cu-β沸石合成的因素。结果表明,按化学组成(物质的量的比)n_SiO2∶n_CuO∶n_(TEA)2O∶n_H2O∶n_NH4F=60∶(0.5~5.0)∶(16~18)∶(550~650)∶(25~50)配制初始反应混合物,可以制备出结晶良好的Cu-β沸石,且Cu原子进入了沸石骨架。所得Cu-β沸石(n_Si/n_Cu=30)在H₂O₂氧化苯酚的羟基化反应中表现出较好的催化活性,苯酚的转化率为25.1%,邻苯二酚和对苯二酚的选择性分别为63.9%和32.5%。     

高酸位多级孔超稳Y型沸石的制备及催化性能

以表面活性剂十六烷基三甲基溴化铵（CTABr）为模板剂,在水热体系对水蒸气处理后的超稳Y型（USY）沸石进行晶化处理,获得高酸量和高水热稳定性的USY-c-w样品。利用X射线衍射、扫描电子显微镜、透射电子显微镜、固态核磁共振、N₂吸附-脱附、NH₃-程序升温脱附、傅里叶变换红外光谱及吡啶红外对所制备催化剂的物化性质进行详细表征。选用1,3,5-三异丙苯（TIPB）催化裂化作为探针反应,研究制备的催化剂的催化性能,并与工业USY沸石进行对比。结果表明,再次水热晶化后,样品的硅铝骨架局部重构,非骨架铝重新进入沸石骨架,合成样品的硅铝比（n_SiO2/n_Al2O3）由10降至3.0;再晶化后的USY沸石,不仅具有丰富的介孔结构,并且具有更多的弱酸和中强酸位点。在TIPB裂解反应中,再晶化后的USY沸石表现出比原样品更优异的催化性能。     

高酸位多级孔超稳Y型沸石的制备及催化性能

以表面活性剂十六烷基三甲基溴化铵(CTABr)为模板剂,在水热体系对水蒸气处理后的超稳Y型(USY)沸石进行晶化处理,获得高酸量和高水热稳定性的USY-c-w样品。利用X射线衍射、扫描电子显微镜、透射电子显微镜、固态核磁共振、N₂吸附-脱附、NH₃-程序升温脱附、傅里叶变换红外光谱及吡啶红外对所制备催化剂的物化性质进行详细表征。选用1,3,5-三异丙苯(TIPB)催化裂化作为探针反应,研究制备的催化剂的催化性能,并与工业USY沸石进行对比。结果表明,再次水热晶化后,样品的硅铝骨架局部重构,非骨架铝重新进入沸石骨架,合成样品的硅铝比(n_Si/n_Al)由10降至3.0;再晶化后的USY沸石,不仅具有丰富的介孔结构,并且具有更多的弱酸和中强酸位点。在TIPB裂解反应中,再晶化后的USY沸石表现出比原样品更优异的催化性能。     

两步变温晶种法制备丝光沸石膜及其渗透汽化乙酸脱水性能

在水热晶种法基础上采用两步变温晶化以高水硅比(n_H2O/n_SiO2)稀溶液配方为合成液,研制用于渗透汽化(PV)乙酸脱水的丝光沸石膜(MOR膜),考察了变温晶化各段时间、水硅比与氟离子对 MOR膜的形貌与分离性能的影响规律。结果表明：高温段晶化时间、水硅比与氟离子对MOR膜的形貌、结晶度和膜层厚度产生显著影响,并影响MOR膜渗透气化分离性能;在高温段(150 ℃)和低温段(120 ℃)的晶化时间分别为 18和 6 h,在水硅比为 60且含氟离子体系中所制备的 MOR膜的性能最佳,其对质量分数50%的乙酸水溶液的渗透通量和分离系数分别为1.45 kg·m^-2·h^-1和1 008。     

斜发沸石的合成研究

采用水热法，分别在物质量的比为2.1Na₂O∶10SiO₂∶Al₂O₃∶110.1H₂O和1.05K₂O∶1.05Na₂O:12SiO₂∶Al₂O₃∶250H₂O的条件下合成出较高纯度斜发沸石，研究了斜发沸石合成的各种影响因素。结果表明，在140、160和180 ℃条件下均能合成出斜发沸石，且提高温度可以缩短斜发沸石的晶化时间；反应混合物的硅铝物质量的比应控制在10～12之间；碱度的降低会导致晶化时间延长，过高的碱度则导致晶种溶解；反应混合物中K⁺的存在利于斜发沸石的晶化。合成斜发沸石对海水中K⁺饱和吸附量达 38.60 mg·g^-1以上，其吸附性能显著优于文献报导的天然斜发沸石。     

类固相法快速合成高钙镁离子交换性能的P型分子筛

以硅铝干凝胶为硅源和铝源,氢氧化钠为碱源,采用类固相法快速合成了P型分子筛,并通过X射线衍射（XRD）、扫描电镜（SEM）等手段对产品进行了表征分析。结果表明,硅铝干凝胶的组成n_SiO2/n_Al2O3=5,晶化时间和晶化温度分别为3 h、140℃,原料的组成n_Na2O/n_SiO2、n_H2O/n_SiO2=18.51时,可制备形貌均一、结晶良好的P型分子筛产品。与传统水热法相比,该方法极大地减少了合成过程的用水量,缩短了晶化时间,提高了产品的钙镁离子交换性能,从整体上优化了P型分子筛的合成工艺。     

一种合成高水热稳定性微孔-介孔复合分子筛β沸石/MCM-41的新方法

首次以β沸石作为硅铝源制备了β沸石/MCM-41微孔-介孔复合分子筛材料，通过XRD、IR、N₂吸附脱附、SEM和水热处理等手段对复合材料进行了表征，并与MCM-41和β沸石及二者的机械混合物的有关性能进行了对比研究。结果表明，复合分子筛明显不同于机械混合物，其水热稳定性远远高于普通方法合成的介孔分子筛，而且发现通过改变体系的n_Na/n_Si比，可以调变复合样品中的微孔、介孔相的相对含量。     

开放骨架磷酸铝AlPO4-12的晶化过程

以乙二胺为结构导向剂,在200℃加热物质的量组成为n_Al2O3:n_P2O5:n_en:n_H2O=1:1:2:226的初始混合物(en=乙二胺),合成了三维开放骨架磷酸铝化合物AlPO₄-12。用X-射线衍射、元素分析、pH测量、液体核磁共振以及电喷雾质谱研究了其晶化过程。依据质谱数据,开发了一个系统枚举在晶化过程中可能生成的小结构单元分子式的方法。研究发现在AlPO₄-12的晶化过程中经历了层状磷酸铝UiO-15和UiO-13中间相,液相中Al物种的浓度极低,在晶化过程中生成的小结构单元中P-OH逐渐增多,乙二胺分子逐渐质子化,在晶化过程中生成了磷酸铝的4元环和6元环。用电喷雾质谱研究晶化过程中的液相可以获得小结构单元的结构和组成信息。     

Synthesis of Zeolite ZSM-2 Using Zeolite NaX as Seeds

Introduction Oxygen and nitrogen have been produced tradition-ally by cryogenic distillation of air. Methods for the non-cryogenic separation based on selective adsorption have been developed and commercialized since the 1970s and have led to a cost-effective process for this important separation.1 Low-silica zeolites are important materials for producing oxygen by selective adsorption of nitrogen. In 19891990, a new generation of lith-ium-based adsorbents was developed.2,3 Highly lithium exc…     

Temperature-programmed desorption of n-hexane from hydrated HZSM-5 and NH4ZSM-5 zeolites

Temperature-programmed desorption coupled with mass spectrometer as a detector (TPD), IR and ¹³C NMR measurements are used to study the adsorption of n-hexane on hydrated HZSM-5 and NH₄ZSM-5 zeolites. The ¹³C NMR measurements show that n-hexane can access the pore structure of ZSM-5 zeolites previously saturated with water. TPD spectra of n-hexane are monitored in the temperature region 50–300°C, in the case of fully or partially hydrated samples; two-stage desorption of n-hexane is found. Simultaneous desorption of water and n-hexane in the same temperature region are found, in all investigated samples.     

Reconstructive and displacive transformations of tectosilicates

By using the thermally induced phase transformation initial zeolites were converted into pure carnegieite, stuffed derivative of cristobalite. The polymorphs obtained from Na-LTA are stoichiometric (NaAlSiO₄), since those obtained from Na-FAU zeolite are non-stoichiometric (Na_1-xAl_1-xSi_1+xO₄). Stoichiometric carnegieite have cubic structure, while non-stoichiometric carnegieite crystallized in cubic and orthorhombic forms. ²⁹Si MAS NMR spectra show a very large but expecting difference between stoichiometric and non-stoichiometric carnegieite. The spectrum of stoichiometric carnegieite has only one peak Si(4Al), while the spectrum of non-stoichiometric carnegieite consist few superimposed peaks assigned to Si(4Al), Si(3Al), Si(2Al), Si(1Al) and Si(0Al). DTA study indicates the occurrence of displacive phase transition of all synthesized carnegieite. The transition temperature is depending on silicon aluminum order: T _m=690°C for stoichiometric, T _m=565 and 660°C for non-stoichiometric, low-temperature and high-temperature carnegieite, respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

异相晶种诱导快速合成低硅菱沸石分子筛

在不含有机模板剂体系(OSDAs)中,利用异相晶种(T型分子筛)诱导快速合成出纯相的低硅菱沸石分子筛。采用XRD、SEM、TEM、27Al MAS NMR和紫外拉曼等手段表征分子筛的结构属性和形貌特点。详细研究了菱沸石分子筛的晶化过程以及晶种添加量、nAl2O3/nSi O2、nH2O/nSiO2和碱度对菱沸石分子筛晶化的影响,并探讨T型分子筛晶种诱导合成菱沸石分子筛的晶化机理。原位合成体系中仅形成L型分子筛晶相,而一定量T型分子筛异相晶种的加入诱导溶胶快速制备出纯相的菱沸石分子筛。T型分子筛晶体在一定的水热条件下不断溶解而释放的六元环(6R)和四元环(4R)迅速形成菱沸石分子筛特征笼(CHA笼),抑制了L型分子筛特征单元和特征笼(不含四元环的CAN笼)的形成。     

Synthesis,characterization, electrochemical study,and antimicrobial activity of bis(benzoylacetonato) vanadium(IV) complexes of biphenylphenols

New non-oxovanadium(IV) complexes of biphenylphenols, [VCl_{2? n} (bzac)₂(OAr^1,2) _n ], have been synthesized in quantitative yields from the reaction of bis(benzoylacetonato)dichlorovanadium(IV) with the trimethylsilyl derivative of 2- and 4-phenylphenols in carbon tetrachloride. The complexes have been characterized by physicochemical, magnetic moment measurements, IR, mass spectra, and electrochemical studies. The thermal behavior of the complexes has been studied by TGA–DTA. The complexes have been screened for their antimicrobial activity against some pathogenic bacteria, Escherichia coli and Staphylococcus aureus and fungi, Candida albicans, Aspergillus niger, and Fusarium oxysporum, by two-fold serial dilution.     

THF-FER沸石的系列研究—Ⅱ．模板剂分子THF的位置

用^13C HPDEC MAS NMR与热分析方法表征了在四氢呋喃（THF）-Na2O-SiO2- Al2O3-H2O体系中水热合成的高硅Na-THF-FER沸石、酸交换后的H-THF-FER沸石以及 吸附于Na-FER和H-FER沸石中的THF。结果证明，模板剂分子THF位于Na-THF-FER沸 石骨架的FER笼内，平衡骨架阳离子Na^+主要存在于十元环孔道；而吸附子FER沸石 中的THF仅处于十元环孔道中，合成样品中THF的化学位移与液态THF相比，向低场 移动，谱线明显变宽，表明THF分子与FER笼之间存在很强的相互作用。     

Physicochemical properties of alkali-metal exchanged type X zeolites

The changes in the physicochemical properties of a series of faujasite type X zeolites cation exchanged with K⁺, Rb⁺ and Cs⁺ have been studied by XRD, IR, thermoanalytical methods and sorption measurements. As a consequence of the enhanced scattering of X-rays by larger alkali metal cations, the percent relative intensity of the XRD peaks of cation exchanged zeolites was found to have decreased considerably. The framework IR spectra also showed analogous changes. The alkali metal exchange was found to enhance the thermal stability of the parent zeolite. The available void volume and specific surface area (obtained by low temperature nitrogen sorption) also decreased with the increase in the degree of exchange and cationic size. Equilibrium sorption capacities (298 K andP/P ₀=0.5) for water,n-hexane, cyclohexane and 1,3,5-trimethylbenzene also exhibited the same trend.NCL communication no. 6056.     

Synergism in the actions of a transition metal cation and a Lewis acid in the liquid- and gas-phase catalytic conversion of alkanes over modified ZSM-5 zeolites under mild conditions

Bimetallic catalysts have been prepared by successively modifying the high-silica zeolite ZSM-5 with cobalt and aluminum salts. The performance of these catalysts in the conversion of higher alkanes at medium temperatures (130–190°C) depends on whether the reaction is conducted in the liquid or gas phase. In both cases, the transition metal and surface-anchored aluminum chloride act synergetically. In the liquid-phase reactions of n-heptane and n-dodecane, the activity of the bimetallic systems is more than one order of magnitude higher than the activity of the hydrogen form of the initial zeolite. New adsorption and catalytic sites resulting from the introduction of the two modifiers into the zeolite have been discovered by diffuse reflectance IR spectroscopy. In particular, the modifiers generate a new state of cobalt in which the transition metal atoms are linked with aluminum atoms through chlorine or oxygen atoms. The liquid-phase conversion of alkanes over the modified zeolites is unlikely to proceed via a carbocationic mechanism.     

CXN天然沸石的研究VII. 骨架高硅超稳化改性

以高硅超稳化辉沸石(STI)为基底沸石, 分别经盐酸脱铝或氟硅酸铵脱铝补硅处理后制备的改性H-STI沸石, 其非骨架铝含量明显减少, 而后者骨架硅铝比进一步提高. X射线荧光散射光谱(XRF), ²⁷Al高分辨率魔角旋转固体核磁共振(MAS NMR), 红外(FT-IR)光谱等表征证明改性后的沸石骨架硅铝原子比分别为6.8和11.4. 低温氮吸附表明, 经盐酸处理的高硅STI沸石孔道开放完美, 但经氟硅酸铵处理的样品孔道被部分堵塞. 分段程序升温焙烧表明前者骨架热稳定性略差, 1000 ℃焙烧后结构基本被破坏, 而后者热稳定性较好, 经相同温度段焙烧后仍保持较高的结晶度和热稳定性, 其结构基本实现超稳化.     

Theoretical study of the adsorption of ethylene on alkali‐exchanged zeolites

The structures of alkali‐exchanged faujasite (X–FAU, X = Li⁺ or Na⁺ ion) and ZSM‐5 (Li–ZSM‐5) zeolites and their interactions with ethylene have been investigated by means of quantum cluster and embedded cluster approaches at the B3LYP/6‐31G(d, p) level of theory. Inclusion of the Madelung potential from the zeolite framework has a significant effect on the structure and interaction energies of the adsorption complexes and leads to differentiation of different types of zeolites (ZSM‐5 and FAU) that cannot be drawn from a typical quantum cluster model, H₃SiO(X)Al(OH)₂OSiH₃. The Li–ZSM‐5 zeolite is predicted to have a higher Lewis acidity and thus higher ethylene adsorption energy than the Li–FAU zeolites (16.4 vs. 14.4 kcal/mol), in good agreement with the known acidity trend of these two zeolites. On the other hand, the cluster models give virtually the same adsorption energies for both zeolite complexes (8.9 vs. 9.1 kcal/mol). For the larger cation‐exchanged Na–FAU complex, the adsorption energy (11.6 kcal/mol) is predicted to be lower than that of Li–FAU zeolites, which compares well with the experimental estimate of about 9.6 kcal/mol for ethylene adsorption on a less acidic Na–X zeolite. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 94: 333–340, 2003