Zeolites最新文献_第7页

Synthesis and characterisation of transition-metal-substituted gallium phosphates with the laumontite structure 具有湖沸石结构的过渡金属取代磷酸镓的合成与表征

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00099-7

Andrew D. Bond, Ann M. Chippindale , Andrew R. Cowley, Jennifer E. Readman, Anthony V. Powell

引用次数: 25

Diffuse reflectance i.r. spectroscopic study on hydroxyl groups of H-ZSM-5s having different sizes and properties h - zsm -5不同尺寸和性质羟基的漫反射红外光谱研究

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00112-7

Shu-Bin Pu, Tomoyuki Inui

引用次数: 19

Solid-state defects in calcined CaA zeolite 煅烧CaA沸石的固态缺陷

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00120-6

Hideyuki Oka, Kunikazu Kamioka, Yuji Tokunaga, Tadashi Okada

引用次数: 2

Synthesis, characterization, and catalytic properties of a novel Germano-aluminophosphate molecular sieve with AEL structure: GeAPO-11 具有AEL结构的新型锗-磷酸铝分子筛:GeAPO-11的合成、表征及催化性能

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00082-1

P. Mériaudeau, Vu A. Tuan, Le N. Hung, G. Szabo

引用次数: 3

Solid-state ion exchange in zeolites: Part 8. Interaction of lanthanum(III) chloride with zeolites under anhydrous conditions 沸石中的固态离子交换:第8部分。无水条件下氯化镧与沸石的相互作用

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00118-8

Bogdan Sulikowski , Josef Find, Hellmut G. Karge, Daniel Herein

引用次数: 24

Alkylation of toluene on HSAPO-5 with various Si concentrations 甲苯在不同硅浓度的HSAPO-5上的烷基化反应

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00116-4

T. Masukawa, T. Komatsu, T. Yashima

{"title":"Alkylation of toluene on HSAPO-5 with various Si concentrations","authors":"T. Masukawa, T. Komatsu, T. Yashima","doi":"10.1016/S0144-2449(97)00116-4","DOIUrl":"10.1016/S0144-2449(97)00116-4","url":null,"abstract":"<div>HSAPO-5 with various Si concentrations was used as a catalyst for the alkylation of toluene with methanol to investigate weak acid sites. On HSAPO-5 with Si/(Al + P + Si) ≦ 0.026, the conversion of toluene increased with time on stream for a certain period, whereas the conversion decreased monotonously on HSAPO-5 with higher Si concentrations. Pretreatment with methanol on HSAPO-5 with Si/(Al + P + Si) = 0.018 increased the initial conversion of toluene. From the measurement of the amount of coke deposited on HSAPO-5, it is suggested that during the initial stage of the reaction coke is mainly produced by the reaction of methanol by itself at the acid sites on the external surface of HSAPO-5 with low Si concentrations. A small amount of coke thus formed would gradually retard the further self-conversion of methanol into coke. Therefore, the fraction of methanol used for the alkylation could increase, resulting in the increase in toluene conversion. It is suggested that the acid sites on the external surface are stronger than those formed by the substitution of Si for P but are weaker than those formed in aluminosilicate regions existing in HSAPO-5 with high Si concentrations.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 429-433"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0144-2449(97)00116-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76089309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Mutinaite, a new zeolite from Antarctica: The natural counterpart of ZSM-5 Mutinaite，一种来自南极洲的新型沸石:ZSM-5的天然对应物

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00100-0

Ermanno Galli, Giovanna Vezzalini, Simona Quartieri, Alberto Alberti, Marco Franzini

{"title":"Mutinaite, a new zeolite from Antarctica: The natural counterpart of ZSM-5","authors":"Ermanno Galli, Giovanna Vezzalini, Simona Quartieri, Alberto Alberti, Marco Franzini","doi":"10.1016/S0144-2449(97)00100-0","DOIUrl":"10.1016/S0144-2449(97)00100-0","url":null,"abstract":"<div>Mutinaite is the third new zeolite from Ferrar dolerites at Mt. Adamson (Northern Victoria Land, Antarctica). The mineral occurs as subspherical aggregates of tiny radiating lath-like fibres or as aggregates of transparent, colourless to pale-milky, tiny tabular crystals; it has vitreous luster, white streak and good 100 cleavage. Mutinaite is brittle with dmeas = 2.14(3) and dcalc = 2.17 g/cm3. Optically, it is biaxial negative with α = 1.485(2), β = 1.487(2) and γ = 1.488(2). The orientation is X = b, Y = a, Z = c. Mutinaite is orthorhombic with a = 20.223(7), b = 20.052(8), c = 13.491 (5)Å, space group Pnma. The strongest powder X-ray diffraction lines are (d(Å), I, hkl): 11.20, 84, 101, 011; 9.98, 35, 200,020; 3.85, 100, 501, 051; 3.75, 98, 303; 3.67, 27, 133; 3.00, 32, 503. The framework topology is that of the synthetic zeolite ZSM-5. The chemical formula is: (Na2.76K0.11Mg0.21Ca3.78)Σ = 6.86(Al11.20Si84.91)Σ=96.11O192 · 60H2O. The Si/Al ratio, equal to 7.6, is the highest found in a natural zeolite. Thermal stability and rehydration capacity are very high. The name is from Mutina, the ancient Latin name of the city of Modena.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 318-322"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0144-2449(97)00100-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88403322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 35

States of aluminum in zeolite β and influence of acidic or basic medium 铝在β沸石中的状态及酸性或碱性介质的影响

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00103-6

Chun Yang, Qinhua Xuaf

{"title":"States of aluminum in zeolite β and influence of acidic or basic medium","authors":"Chun Yang, Qinhua Xuaf","doi":"10.1016/S0144-2449(97)00103-6","DOIUrl":"10.1016/S0144-2449(97)00103-6","url":null,"abstract":"<div>The states of aluminum in zeolites β were investigated in detail with FTIR spectroscopy. Three kinds of aluminum—framework, nonframework, and transient-state aluminum—were detected in template-removed zeolite β. The states of aluminum in our samples intensely depends on the nature of compensating cation, consistent with the conclusion of Brougeat-Lami et al. But some new assignments of aluminum species and new opinions about the states of aluminum and their transformation are proposed. From the experimental results, we suggest that, because the framework of zeolite β is deformable, the distortion and the tension of zeolite lattice occur when protons, which possess high electron affinity, are located at cationic sites, leading to the breakage of Al-O bond and the removal of aluminum. Therefore, zeolite β is subjected to dealumination in acidic medium. On the other hand, the high deformability also results in the relaxation of zeolite structure when H+ is replaced by other cations (e.g., Na+) so that transient-state aluminum and even nonframework aluminum can go back into the framework. Owing to ion-exchange, the cationic nonframework aluminum species enter the solution; moreover, it can also reinsert into the framework after hydroxylation in basic medium.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 404-410"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0144-2449(97)00103-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80331219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 71

Degree of crystallinity of dealuminated offretites determined by X-ray diffraction and by a new method based on nitrogen adsorption 用x射线衍射和氮吸附新方法测定脱铝铝石的结晶度

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00101-2

A.P. Carvalho, M. Brotas de Carvalho, J. Pires

{"title":"Degree of crystallinity of dealuminated offretites determined by X-ray diffraction and by a new method based on nitrogen adsorption","authors":"A.P. Carvalho, M. Brotas de Carvalho, J. Pires","doi":"10.1016/S0144-2449(97)00101-2","DOIUrl":"10.1016/S0144-2449(97)00101-2","url":null,"abstract":"<div>Samples obtained from thermal dealumination (in the presence and absence of water vapour) of three offretite zeolites with, respectively, 4.4, 3.4, and 2.9 aluminium atoms per unit cell, were investigated by i.r. spectroscopy. X-ray diffraction, and nitrogen adsorption. The percentage of crystallinity was then evaluated by two different methods: the standard XRD technique and a new method based on nitrogen adsorption data analysed through the αs-method. In this case the volume of the ultramicropores (width less than 0.7 nm) was considered. Differences between the two estimates, as well as the loss of crystallinity during dealumination, which is expressed by the representation of both crystallinity evaluations, CXRD or CADS, versus ν1 (the frequency of the stretching asymmetric T-O band), were analysed for self-steamed and steamed samples. The results obtained agree within 20%, and often better. For self-steamed samples the crystallinity evaluated from XRD patterns is always smaller than that estimated from adsorption data, whereas for steamed samples the opposite situation is generally observed.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 382-386"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0144-2449(97)00101-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86992789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Zeolite cycle sequences 沸石循环序列

Zeolites Pub Date : 1997-11-01 Epub Date: 1998-04-14 DOI: 10.1016/S0144-2449(97)00122-X

G. Thimm, W.E. Klee

引用次数: 9