Zeolites最新文献_第8页

Announcing the merger of Zeolites and Microporous Materials 宣布沸石和微孔材料合并

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00123-1

Lovat V.C. Rees (Professor), Robert W. Thompson (Professor)

引用次数: 0

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 DOI: 10.1016/S0144-2449(97)00101-2

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

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引用次数: 13

Crystal structure of the zeolite mutinaite, the natural analog of ZSM-5 该沸石的晶体结构为异沸石，是ZSM-5的天然类似物

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00124-3

Giovanna Vezzalini, Simona Quartieri, Ermanno Galli, Alberto Alberti, Giuseppe Cruciani, Ake Kvick

引用次数: 55

The transformation of kaolin to low-silica X zeolite 高岭土向低硅X型沸石的转化

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00132-2

Deepak Akolekar, Alan Chaffee, Russell F. Howe

{"title":"The transformation of kaolin to low-silica X zeolite","authors":"Deepak Akolekar, Alan Chaffee, Russell F. Howe","doi":"10.1016/S0144-2449(97)00132-2","DOIUrl":"10.1016/S0144-2449(97)00132-2","url":null,"abstract":"<div>The thermal transformation of kaolin extrudates to metakaolin and the subsequent crystallization of low-silica X extrudates has been investigated by X-ray diffraction, scanning electron microscopy, FTIR spectroscopy, N2-adsorption, 27Al and 29Si MAS NMR, and surface analysis. Kaolin transforms to metakaolin at 973 K. The macroporous metakaolin extrudates are converted to zeolite X plus a small amount of zeolite A in alkaline solution at 324 K. The 27Al NMR signals of octahedral and pentacoordinated aluminium in metakaolin are removed after 30 min at 324 K, whereas the first XRD features of zeolites X and A are not detected until 48 h. Likewise, 29Si NMR and FTIR spectra show that zeolite is first present at 48 h synthesis time. The amount of zeolite A decreases with increasing synthesis time, but there is an overall increase in product crystallinity and surface area up to 240 h. SEM analyses show that zeolite crystals first form in the interior of extrudates at the edges of macropores; with time the metakaolin matrix is consumed to produce well-crystalline zeolite extrudates consisting of ca. 95% low-silica X and 5% zeolite A.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 359-365"},"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)00132-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76804576","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: 153

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00137-1

V. Termath

引用次数: 0

Enterex: Anti-diarrheic drug based on purified natural clinoptilolite Enterex:以纯天然斜沸石为基础的止泻药物

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00087-0

G. Rodríguez-Fuentes, M.A. Barrios, A. Iraizoz, I. Perdomo, B. Cedré

引用次数: 139

Spectroscopic and catalytic evidence for the incorporation of gallium in the AEL framework 光谱和催化证据的结合镓在AEL框架

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00113-9

Francisco J. Machado, Carmen M. López, José Goldwasser, Bernardo Méndez, Yván Campos, Douglas Escalante, Miguel Tovar, María M. Ramírez-Agudelo

{"title":"Spectroscopic and catalytic evidence for the incorporation of gallium in the AEL framework","authors":"Francisco J. Machado, Carmen M. López, José Goldwasser, Bernardo Méndez, Yván Campos, Douglas Escalante, Miguel Tovar, María M. Ramírez-Agudelo","doi":"10.1016/S0144-2449(97)00113-9","DOIUrl":"10.1016/S0144-2449(97)00113-9","url":null,"abstract":"<div>71Ga MAS n.m.r. analysis and the catalytic behavior during the transformation of 1-butene and n-butane strongly suggest the incorporation of Ga into the AlPO4-11 (AEL) framework during the synthesis of GaAPSO-11. A unique clear signal at around +120 ppm is proposed to be associated with the presence of tetrahedral Ga in the AEL framework of the unmodified GaAPSO-11. Migration of structural Ga atoms to the silicon domain of the AEL framework seems to occur as a result of a mild hydrothermal treatment, giving rise to an additional signal at +156 ppm, previously associated with tetrahedral gallium in gallosilicates with the MFI topology. The fact that GaAPO-11 and GaAPSO-11 behaved in a way similar to their counterparts AlPO4-11 and SAPO-11 during the skeletal isomerization of n-butenes reinforces the idea of an isomorphous substitution of Al(III) by Ga(III) in the AEL framework. The transformation of n-butane was shown to be a valuable test for detecting the presence of small amounts of hydro-dehydrogenating extraframework gallium species (EFGS) in Ga-supported SAPO-11 (Ga/SAPO-11). The fact that the sample of GaAPSO-11 was completely inactive for this transformation leads us to believe that the incorporation of gallium into the tetrahedral positions of the AEL framework was almost complete.</div>","PeriodicalId":23983,"journal":{"name":"Zeolites","volume":"19 5","pages":"Pages 387-394"},"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)00113-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86823635","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: 11

On the synthesis of nitrate enclathrated sodalite in organic solvents 有机溶剂中硝酸包合钠石料的合成

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00098-5

M. Fechtelkord, B. Posnatzki, J.-Chr. Buhl

引用次数: 10

Hydrothermal synthesis of alkali cation heulandite aluminosilicate molecular sieves 水热合成碱阳离子水镁铝硅酸盐分子筛

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00134-6

Dongyuan Zhao, Larry Kevan, Rosemarie Szostak

引用次数: 13

Zeolite-catalyzed chlorination of toluene by sulfuryl chloride: The role of sulfuryl chloride decomposition in chlorination 沸石催化硫酰氯对甲苯的氯化反应:硫酰氯分解在氯化反应中的作用

Zeolites Pub Date : 1997-11-01 DOI: 10.1016/S0144-2449(97)00119-X

Brian W. Satterley, Michael C. Hausladen , Carl R.F. Lund

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引用次数: 5