ZSM—5芳构化反应活性和稳定性的研究

ＺＳＭ－５以其独特的基于微孔结构特征的形状选择性和强酸中心，而成为具有酸催化择形性能的新型分子筛催化剂．ＺＳＭ－５分子筛表面酸性中心不但是反应的活性中心，同时也是积炭中心，这使得这类催化剂不仅具有很高的催化反应活性，同时也具有较高的结焦活性．催化剂表...     

Characterization of alkali exchanged ZSM5 by IR spectrosopy

The use of time resolved FTIR spectroscopy for characterizing time dependent adsorbate concentrations has been demonstrated with the examples of adsorption/desorption of ammonia and of adsorption and reactions of propan-2-ol. Adsorption sites and adsorbate structures are discussed.     

Influence of lead on propane aromatization over Pt/ZSM5 catalysts

Aromatization of propane has been investigated over Pt-Pb/ZSM5. Addition of Pb decreases propane conversion with a corresponding increase in the aromatic selectivity. Hydrogenolysis reactions are inhibited by the presence of lead.

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Pt–Pb/ZSM-5. Pb . .

     

Thermal analysis of the synthetic zeolite ZSM5 and its silver iodide form

TG, DTG and DTA measurements were used to study the thermal properties of the synthetic zeolite ZSM5, its silver form (Ag-ZSM5) and a zeolitic product containing silver iodide (K-ZSM5/AgI). Thermoanalytical measurements were supplemented by morphology studies.The authors wish to thank Dr. J. Brianin, CSc. from Institute of Materials Research of Slovac Academy Sciences for the measurement of scanning electron micrographs.     

PREPARATION OF SILICALITE-1 AND ZSM-5 ZEOLITE/ CERAMIC COMPOSITE MEMBRANES

ＰＲＥＰＡＲＡＴＩＯＮＯＦＳＩＬＩＣＡＬＩＴＥ┐１ＡＮＤＺＳＭ┐５ＺＥＯＬＩＴＥ／ＣＥＲＡＭＩＣＣＯＭＰＯＳＩＴＥＭＥＭＢＲＡＮＥＳＺｈａｎｇＬｉｘｉｏｎｇ，ＪｉａＭｅｎｇｄｏｎｇ，ＭｉｎＥｎｚｅ（ＲｅｓｅａｒｃｈＩｎｓｔｉｔｕｔｅｏｆＰｅｔｒｏｌｅ...     

Na，NBA－Ga－Si－ZSM－5杂原子沸石分子筛的表征

Ｎａ，ＮＢＡ┐Ｇａ┐Ｓｉ┐ＺＳＭ┐５杂原子沸石分子筛的表征高志贤程昌瑞谭长瑜李源（中国科学院山西煤炭化学研究所，太原０３０００１）关键词Ｇａ－Ｓｉ－ＺＳＭ－５沸石分子筛，正丁胺，表征，模板作用近年来的研究结果表明，使用不同类型的有机胺或醇作引导剂，甚...     

Thermochemical properties of copper forms of zeolite ZSM5 containing dimethylethylenediamine

Synthetic zeolite ZSM5 and its copper forms containing N,N-dimethylethylenediamine (dmen) have been investigated by CHN, energy dispersive spectroscopy (EDS) analysis, X-ray powder diffractometry, X-ray photoelectron spectroscopy and continuous waves hydrogen nuclear magnetic resonance (CW ¹H NMR) spectroscopy. Thermal properties have been studied by methods of thermal analysis—TG, DTA and DTG in the temperature range 20-1000 °C in air atmosphere. Mass spectroscopy method was used for the study of the released gas products of thermal decomposition.The results of thermal analyses of two zeolitic samples Cu-ZSM5 and Cu(dmen)_xZSM5 (x depends on the mode of preparation) demonstrated their different thermal properties. The main part of the decomposition process of the samples Cu(dmen)_xZSM5 occurs at considerably higher temperatures than the boiling point of dimethylethylenediamine, proving strong bond and irreversibility of dmen-zeolite interaction. According to the results of mass spectroscopy the decomposition process in inert atmosphere is characterized by the development of a large spectrum of products with atomic mass from 18 to 447 atomic mass units as a consequence of the catalytic effect of the silicate surface.     

Preparation and characterization of a composite of silver iodide and synthetic zeolite ZSM5

A composite material made up of AgI and the potassium form of the synthetic zeolite ZSM5 has been prepared by treating the silver form of ZSM5 with potassium iodide. The composite has been characterised by X-ray powder diffractometry, IR and X-ray photoelectron spectroscopy, electron microsonde analyses and ac conductivity measurements. The Agl content in the composite material is 11.5%. On the basis of the conductivity data obtained for the composite material as well as for K-ZSM5, Ag-ZSM5, microcrystalline AgI and a physical mixture of AgI and K-ZSM5, it has been inferred that, in the composite material, AgI forms a thin conductive shell on the surface of the K-ZSM5 particles.     

以水热法于ZSM-5分子筛中分散MoO3的研究

热扩散法的ＭｏＯ３最高分散量为每克ＺＳＭ－５上０．０８克ＭｏＯ３．而本文采用水热分散法可使ＭｏＯ３在ＺＳＭ－５分子筛中的分散量大大提高．当分散量高达每克ＺＳＭ－５上０．３克ＭｏＯ３时，通过ＸＲＤ，ＩＲ，ＤＴＡ谱测试和吸附测定，都证实了ＭｏＯ３在ＺＳＭ－５中仍然是以非晶相分散态存在．此时，样品有吸附自重６％的水的吸附能力和相应的孔道．     

Calorimetric study of room temperature adsorption of N2O and CO on Cu(II)-exchanged ZSM5 zeolites

Copper ion-exchanged ZSM5 zeolites have been prepared with different cooper loadings from under- to over-exchanged levels. The adsorptions of N₂O and CO at 303 K have been studied using calorimetric method and infrared spectroscopy. The samples were additionally characterised by ammonia adsorption at 423 K. The active sites for both N₂O and CO are Cu(I) ions, which were formed as a result of pre-treatment in vacuum at 673 K.

Room temperature adsorption of nitrous oxide at low equilibrium pressures (up to 66.7 Pa) resulted in small amounts of chemisorbed N₂O (<0.2 molecule per one Cu ion). Differential heats of N₂O adsorption between 80 and 30 kJ/mol were obtained. Differential heats of CO adsorption between 140 and 40 kJ/mol were obtained. The obtained amounts of chemisorbed species in the investigated systems and the values of differential heats of both nitrous oxide and carbon monoxide demonstrate the dependence on the copper content.     

中孔MCM—41分子筛在微孔沸石ZSM—5上附晶生长的研究

首次在微孔沸石ＺＳＭ５表面进行了ＭＣＭ４１分子筛的附晶生长，并首次提出中孔材料ＭＣＭ４１分子筛静电组配理论的新形式（ＸＳ＋Ｉ）；同时利用ＸＲＤ、ＴＥＭ、ＢＥＴ等测试手段表征了合成样品，并讨论了微孔沸石表面附晶生长中孔分子筛ＭＣＭ４１的合成化学，考察了Ｆ离子效应、ｐＨ值及表面活性剂ＣＴＡＢ（十六烷基三甲基溴化铵）的影响。     

Study of Copper Forms of the Synthetic Zeolite ZSM5 Containing Ethylenediamine

Synthetic zeolite ZSM5 and its copperforms containing ethylenediamine (en) have beeninvestigated by X-ray powder diffractometry, NMR andX-ray photoelectron spectroscopies, CHN, EDS andthermal analyses. Copper cations exchanged into thechannels of synthetic zeolite ZSM5 formed coordinationcomplexes with ethylenediamene. By different modes ofpreparation we obtained three Cu-en-ZSM5 zeoliticproducts with different composition, colour and otherproperties. The content of the ethylenediamine in thezeolitic products was 1.5–6 wt.% (dependent ofthe mode of preparation).     

轻烃在改性ZSM－5催化剂上转化成芳烃与低碳烯烃的选择性控制

研究了Ｃ３－Ｃ９烷烃在不同的改性ＺＳＭ－５沸石上的反应规律．过渡金属离子改性的ＺＳＭ－５沸石显示了较高的芳烃选择性，芳烃的选择性还取决于改性金属离子的脱氧能力并可通过预硫化得到改进．钾、钡改性的沸石显示了较高的烯烃选择性，增加钾含量，烯烃选择性显著提高，但也明显抑制了催化剂的活性；提高Ｂａ含量，同样可提高烯烃选择性，但对活性影响不大．环己烯的模型反应结果表明，Ｋ，Ｂａ的作用在于抑制了双分子氢转移反应和提高了脱氢能力．红外表征结果表明，沸石表面的羟基，因不同金属改性而发生不同的变化．此外，气相氧对提高烯烃和芳烃的收率有明显作用     

气固相同晶取代法制备Ti-ZSM-5及其催化性能的研究

以Ｂ－ＺＳＭ－５沸石为母体,经过盐酸洗涤脱硼后,采用气固相同晶取代法制备了Ｔｉ－ＺＳＭ－５沸石．考察了制备条件如反应温度、反应时间和载气流速等对产品沸石中钛物种的配位状态和含量的影响．发现进入Ｔｉ－ＺＳＭ－５骨架中的钛含量存在一个极限值．ＦＴ－ＩＲ、ＵＶ－Ｖｉｓ表征技术和丙烯环氧化反应结果表明：不同气固相反应条件下制备的Ｔｉ－ＺＳＭ－５沸石具有不同的物化性质．骨架钛含量高而非骨架钛含量低的钛沸石具有较高的丙烯环氧化催化活性．     

乙二胺在ZSM-5分子筛催化剂上脱氨制哌嗪

研究了反应温度、反应物浓度及空速对乙二胺在ＨＺＳＭ５和ＫＺＳＭ５分子筛催化剂上转化为哌嗪反应的影响．在反应温度为３４０℃，乙二胺浓度为５０％和空速为２３ｈ－１条件下，乙二胺在２６％ＫＺＳＭ５催化剂上的转化率为９５％，哌嗪的选择性为９６％．与此同时，用ＮＨ３ＴＰＤ和吡啶ＩＲＴＰＤ确定反应是在弱酸部位Ｌ酸中心上进行的，并依此推测了反应机理．     

Isolation of rhenium and ReOx species within ZSM5 channels and their catalytic function in the activation of alkanes and alkanols

Synthesis protocols, structures, and reactivity of Re-oxo species grafted onto H-ZSM5, and their subsequent conversion to Re-clusters through contact with H2 or CH4 were studied by using Raman, infrared, and X-ray absorption spectroscopies. Reactivity measurements by using alkane and alkanol reactants were also examined. Sublimation of Re(2)O(7) at 723 K led to a stoichiometric exchange with each ReO(x) species replacing one proton. Raman features for Re(2)O(7) disappeared during thermal treatment and Raman bands assigned to distorted-tetrahedral Si-O(f)ReO(3)-Al (O(f): zeolite-lattice oxygen atoms) species emerged; infrared bands for acidic OH groups in H-ZSM5 weakened concurrently. X-ray absorption near-edge and fine-structure spectra detected the formation of distorted-tetrahedral Re7+-oxo species during thermal treatment of Re(2)O(7)/H-ZSM5 mixtures in air, and their subsequent reduction to Re(0) in H2 or CH4 to form encapsulated Re metal clusters similar in diameter (approximately 8 A) to the channel intersections in ZSM5. Si-O(f)ReO(3)-Al species in ReO(x)-ZSM5 catalyzed the oxidative conversion of C(2)H(5)OH to acetaldehyde, acetal, and ethyl acetate with very low selectivity to CO(x) (<1 %). Unprecedented turnover rates were exhibited at temperatures much lower than previously found for ReO(x)-based catalysts, and without deactivation or sublimation processes ubiquitous in crystalline Re7+ compounds at temperatures required for catalysis. Encapsulated Re metal clusters formed by the reduction of Si-O(f)ReO(3)-Al precursors led to CH4 pyrolysis and C(3)H(8) dehydrocyclodimerization rates (per Re) that are higher than those previously reported for zeolite-based catalysts. The rate of CH4 conversion to benzene, by using Re-ZSM5, was approximately 30 % higher than that of the best reported catalysts, based on encapsulated MoC(x) clusters, whereas C(2)H(4) and C6+ arene selectivities were similar. C(3)H(8) activity and selectivity of Re-ZSM5 was significantly higher than that of Ga-ZSM5, the best reported catalyst for these reactions. Reaction rates (per Re) were independent of the Re/Al(f) (Al(f): aluminum framework) ratio for both Re and ReO(x) species. This is consistent with the uniform character of the structures formed during grafting of the ReO(x) species through sublimation and their ability to retain their homogeneity even after their reduction to encapsulated Re-clusters.     

Studies of coke distribution in high-silica ZSM zeolites

A method for studying coke distribution in zeolites is suggested. It has been established that two forms of coke can form: one is intracrystalline and the other is located on the outer surface of ZSM zeolites.

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锌,锰对K—Fe／ZSM—48CO加氢催化反应性能的影响

锌、锰对ＫＦｅ／ＺＳＭ４８ＣＯ加氢催化反应性能的影响范彬彬马静红樊卫斌李瑞丰曹景慧（太原工业大学精细化工研究所，太原０３００２４）关键词ＣＯ加氢，ＺＳＭ４８，助剂效应ＫＦｅ／ＺＳＭ４８在一氧化碳加氢合成低碳烯烃的反应中表现出良好的性能。沸石载体不仅...     

直接法ZSM－5沸石分子筛骨架铝的迁脱规律

直接法ＺＳＭ┐５沸石分子筛骨架铝的迁脱规律张悝项寿鹤刘上垣王敬中李赫日亘（南开大学化学系，天津３０００７１）关键词直接法，ＨＺＳＭ－５沸石，脱铝，水热处理ＨＺＳＭ－５沸石分子筛骨架铝的迁脱与其催化活性和稳定性密切相关．汪树军等［１］的研究得到了一些有...     

甲苯,甲醇苯环烷基化ZSM—5沸石催化剂的吸附量热研究

研究了甲苯、甲醇在一系列ＺＳＭ－５沸石催化剂上生成二甲苯的烷基化反应，以Ｈ３为探针分子，用微分吸附量热法表征了这些催化剂的酸性，并与催化活性关联。结果发现，ＨＺＳＭ－５沸石上既有强酸位，又有弱酸位，反应产物为热力学平衡组成的二甲苯异构体，浸渍了镁之后，强酸位被中和ＭｇＺＳＭ－５（２），吸附热位于１３４－８０ｋＪ／ｍｏｌ之间，弱酸位吸附热和要品单位面积上的吸覆盖度几乎没变。ＭｇＺＳＭ－５（２）沸石上