Microporous Materials最新文献_第6页

Synthesis of AlPO4-16 from fluoride-containing media in the presence of various organic templates 含氟介质在不同有机模板存在下合成AlPO4-16

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00040-0

L Schreyeck, P Caullet, J.C Mougenel, J Patarin, J.L Paillaud

引用次数: 11

The crystal morphology of zeolite A. The effects of the source of the reagents 沸石的结晶形态A.试剂来源的影响

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00051-5

Catherine I Round, Susan J Hill, Kay Latham, Craig D Williams

{"title":"The crystal morphology of zeolite A. The effects of the source of the reagents","authors":"Catherine I Round, Susan J Hill, Kay Latham, Craig D Williams","doi":"10.1016/S0927-6513(97)00051-5","DOIUrl":"10.1016/S0927-6513(97)00051-5","url":null,"abstract":"<div>This study investigates the effects of the variation in reagents on the synthesis of zeolite A. The synthesis was attempted under autogenic conditions and at temperatures of 100 (±1)°C and 70(±1)°C, using various aluminium and silicon sources. Preparation of the gels used silica and aluminium to form mixed systems of organic and inorganic reagent sources. Products formed were analysed and characterised instrumentally using X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, thermogravimetric analysis and scanning electron microscopy. Systems using aluminium isopropoxide consistently produced uniformly sized crystals, each having deep, chamfered edges. Sodium reagent sources produced sharp edged crystals. The system using tetraethyl-orthosilicate with aluminium powder produced a hexagonal morphology. The change in the hydroxide concentrations, relative to the systems using sodium silicate and sodium aluminate sources was also monitored, and while it had a marked effect on crystallinity and stability, the crystal morphology remained consistent.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 3","pages":"Pages 213-225"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00051-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88524572","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: 21

Zeolite acidity ranking by the framework–sorbate interaction energy simulation 通过框架-山梨酸相互作用能模拟对沸石酸性进行排序

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00042-4

Kazuo Teraishi, Koichi Akanuma

引用次数: 5

Synthesis of a zeolitic thin layer by a vapor-phase transport method: appearance of a preferential orientation of MFI zeolite 气相输运法合成沸石薄层:MFI沸石优先取向的出现

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00019-9

Eiichi Kikuchi , Kazuhiko Yamashita , Sachioko Hiromoto , Korekazu Ueyama , Masahiko Matsukata

{"title":"Synthesis of a zeolitic thin layer by a vapor-phase transport method: appearance of a preferential orientation of MFI zeolite","authors":"Eiichi Kikuchi , Kazuhiko Yamashita , Sachioko Hiromoto , Korekazu Ueyama , Masahiko Matsukata","doi":"10.1016/S0927-6513(97)00019-9","DOIUrl":"10.1016/S0927-6513(97)00019-9","url":null,"abstract":"<div>Zeolitic membranes were synthesized on a porous alumina support by the vapor-phase transport method using one of two alumina sources: aluminum sulfate and sodium aluminate. By choosing the appropriate period and temperature for drying the aluminosilicate gel on the alumina support, MOR, FER and MFI could be synthesized. MOR was formed when the water content in the dry gel was high. As the water content decreased, FER and MFI were formed sequentially. Preferential formation of MFI was achieved by treating the dry gel at 373  <!-->K, a preferentially oriented MFI membrane could be synthesized, as the (a00) and (0b0) crystal faces were oriented in parallel to the surface of porous alumina support. The uniform and dense morphology of the dry gel seems to account for the appearance of the orientation.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 3","pages":"Pages 107-116"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00019-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78406849","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: 37

Synthesis of VPI-8. II. Mechanism of crystallization VPI-8的合成。2结晶机理

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00032-1

M Yoshikawa , S.I Zones , M.E Davis

引用次数: 6

Magnetic susceptibility effect on the 19F chemical shift of p-fluoroacetophenone molecules adsorbed in FAU and MFI zeolites 磁化率对FAU和MFI沸石吸附对氟苯乙酮分子19F化学位移的影响

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00043-6

A Simon, L Delmotte, J.M Chézeau

引用次数: 1

Sorption of n-pentane, 2-methylbutane and cyclopentane in microporous AlPO4-5 微孔AlPO4-5对正戊烷、2-甲基丁烷和环戊烷的吸附

Microporous Materials Pub Date : 1997-09-01 DOI: 10.1016/S0927-6513(97)00046-1

Bharat L. Newalkar , Raksh. V. Jasra , Vinayak Kamath , S.G.T. Bhat

{"title":"Sorption of n-pentane, 2-methylbutane and cyclopentane in microporous AlPO4-5","authors":"Bharat L. Newalkar , Raksh. V. Jasra , Vinayak Kamath , S.G.T. Bhat","doi":"10.1016/S0927-6513(97)00046-1","DOIUrl":"10.1016/S0927-6513(97)00046-1","url":null,"abstract":"<div>Sorption isotherms for n-pentane, 2-methylbutane and cyclopentane in the aluminophosphate molecular sieve AlPO4-5 are reported at 303, 313, 323 and 333K. The sorption data were fitted into Langmuir, Sips and Dubinin–Radushkevich isotherms. The heats of sorption at zero coverage determined from the data in the Henry region are in the order 2-methylbutane>cyclopentane>n-pentane. Free energy and entropy changes and heats of sorption for these sorbates at various sorption coverages were also determined from the sorption data. The heat of sorption for n-pentane varies only marginally with sorption coverage. However, the heats of sorption for 2-methylbutane and cyclopentane increase significantly with the coverage indicating an increase in sorbate–sorbate interactions. The dependence of thermodynamic properties like the free energy of sorption (ΔG) and the entropy change (ΔS) for 2-methylbutane and cyclopentane on coverage show a sharp decrease and increase at sorption coverages 0.1–0.2mmolg−1 suggesting the rearrangement of molecular packing in the sorbed phase. These observations have been explained in terms of molecular interactions between the AlPO4-5 channels and sorbate molecules.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 3","pages":"Pages 195-205"},"PeriodicalIF":0.0,"publicationDate":"1997-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00046-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81964367","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: 14

N-Alkylation of aniline over silica and montmorillonite K10: the influence of oxide impregnation 苯胺在二氧化硅和K10蒙脱土上的n -烷基化反应:氧化物浸渍的影响

Microporous Materials Pub Date : 1997-08-01 DOI: 10.1016/S0927-6513(97)00029-1

Sankarasubbier Narayanan, Kiranmayi Deshpande

引用次数: 7

Mechanisms of molecular motion of Mo(CO)6 in zeolites NaY and HY from 13C-NMR lineshapes Mo(CO)6在NaY和HY分子筛中的分子运动机理

Microporous Materials Pub Date : 1997-08-01 DOI: 10.1016/S0927-6513(97)00026-6

H. Koller , A.R. Overweg , L.J.M. van de Ven , J.W. de Haan , R.A. van Santen

{"title":"Mechanisms of molecular motion of Mo(CO)6 in zeolites NaY and HY from 13C-NMR lineshapes","authors":"H. Koller , A.R. Overweg , L.J.M. van de Ven , J.W. de Haan , R.A. van Santen","doi":"10.1016/S0927-6513(97)00026-6","DOIUrl":"10.1016/S0927-6513(97)00026-6","url":null,"abstract":"<div>The potential of 13C-NMR spectroscopy of stationary samples for the study of mechanisms of anisotropic molecular motion of Mo(CO)6 adsorbed in zeolites has been examined. Free diffusional rotation or jump processes about the various symmetry axes of the octahedral complex cause motional averaging of 13C chemical shift anisotropy, allowing for the characterization of the different motional mechanisms. At 110 K a large portion of the Mo(CO)6 molecules is firmly fixed in zeolites NaY and HY as indicated by a broad (ca. 410 ppm) chemical shift powder pattern. A narrow 13C-NMR component is observed in both zeolites for molecules undergoing isotropic motion or rotation about a three-fold axis. An additional line, which is inverted in shape and reduced in width by a factor of −1/2 compared to the rigid case, is only observed for NaY. This line is assigned to molecules undergoing free rotation about the four-fold axis, but it may also be due to Mo(CO)6 jumping about a two-fold axis. The changes in the distribution of molecules in different motional states was explored between 110 K and ambient temperature. Molecules undergoing rotations or jumps about the four- or two-fold axes only exist in NaY at lower temperatures when stationary Mo(CO)6 molecules are also present. At 180 K and higher temperatures, rotation about the three-fold axis or isotropic motion are the sole types of molecular motion.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 1","pages":"Pages 9-17"},"PeriodicalIF":0.0,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00026-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81651509","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: 2

Further investigations on the synthesis of pure-silica molecular sieves via the use of organic structure-directing agents 有机定向结构剂合成纯二氧化硅分子筛的进一步研究

Microporous Materials Pub Date : 1997-08-01 DOI: 10.1016/S0927-6513(97)00024-2

K. Tsuji, M.E. Davis

{"title":"Further investigations on the synthesis of pure-silica molecular sieves via the use of organic structure-directing agents","authors":"K. Tsuji, M.E. Davis","doi":"10.1016/S0927-6513(97)00024-2","DOIUrl":"10.1016/S0927-6513(97)00024-2","url":null,"abstract":"<div>Several organic structure-directing agents (SDAs) that are variations of a 4,4′-trimethylenebis(N-methyl, N-R1-piperidinium) moiety were synthesized and used for the synthesis of pure-silica molecular sieves. Pure-silica MTW, MFI, BEA and the MCM-41-type mesoporous materials could be prepared by changing only the R1 group. When R1 was pentyl or hexyl, MFI was crystallized, suggesting that each SDA molecule spans two channel intersections. For R1 groups smaller than pentyl, MTW was formed. Pure-silica BEA could easily be prepared when R1 was benzyl or cyclohexylmethyl. Numerous variations of the organics used to crystallize BEA were explored and the features necessary to structure direct the formation of BEA elucidated. When R1 was either octyl or nonyl, the MCM-41-type mesoporous materials were formed, indicating that these organics can act as surfactants. The results presented provide further evidence that organic molecules can serve as structure-directing agents for the synthesis of pure-silica molecular sieves.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"11 1","pages":"Pages 53-64"},"PeriodicalIF":0.0,"publicationDate":"1997-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00024-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75177970","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: 24