Microporous Materials最新文献_第9页

Isopropylation of polynuclear aromatic hydrocarbons on Al-containing M41S mesoporous catalysts 多核芳烃在含铝M41S介孔催化剂上的异丙化反应

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00124-1

S.B. Pu, J.B. Kim, M. Seno, T. Inui

{"title":"Isopropylation of polynuclear aromatic hydrocarbons on Al-containing M41S mesoporous catalysts","authors":"S.B. Pu, J.B. Kim, M. Seno, T. Inui","doi":"10.1016/S0927-6513(96)00124-1","DOIUrl":"10.1016/S0927-6513(96)00124-1","url":null,"abstract":"<div><p>MCM-48 with Al incorporated into the walls constructing its mesopores (Al-MCM-48) was synthesized by a hydrothermal method. Al-MCM-48 possesses almost the same surface area, thermal stability and pore size as MCM-48, and has an acidity equivalent to Al-MCM-41. However, in the isopropylation of naphthalene, Al-MCM-48 exhibits a higher activity than Al-MCM-41. This is attributed to its larger pore size and three-dimensional pore system, which is more advantageous for molecular diffusion than the relatively narrow and one-dimensional pore system of Al-MCM-41. Compared with the yields of 2,6-diisopropylnaphthalene on large-pore zeolites, those on A1-M41S (Al-MCM-41 and Al-MCM-48) are not high because of their fewer acid sites. Al-MCM-48 also shows a higher activity than Al-MCM-41 in the isopropylation of pyrene, and the activities on the mesoporous M41S materials were much higher than that on zeolite Y. Isopropylation of pyrene occurs inside the mesopores of M41S, while pyrene derivatives cannot be produced inside the micropores of zeolite Y. However, coke formation and adsorption of the reactant and/or product proceeded in the mesoporous channels and caused catalyst deactivation. The product distributions, especially the ratio of 2-isopropylpyrene/1-isopropylpyrene in pyrene isopropylation, indicate that shape selectivity occurs inside the regular mesopores of M41S.</p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 1","pages":"Pages 25-33"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(96)00124-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91480430","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: 49

Orientation of the acidity probes benzene, acetonitrile and pyridine in SAPO-5 and GaAPO-5 molecular sieves: an FTIR microscopy study 酸性探针在SAPO-5和GaAPO-5分子筛中苯、乙腈和吡啶的取向:FTIR显微镜研究

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00126-5

W.P.J.H. Jacobs , D.G. Demuth , S.A. Schunk , F. Schüth

{"title":"Orientation of the acidity probes benzene, acetonitrile and pyridine in SAPO-5 and GaAPO-5 molecular sieves: an FTIR microscopy study","authors":"W.P.J.H. Jacobs , D.G. Demuth , S.A. Schunk , F. Schüth","doi":"10.1016/S0927-6513(96)00126-5","DOIUrl":"10.1016/S0927-6513(96)00126-5","url":null,"abstract":"<div><p>The adsorption and desorption behaviour of benzene, acetonitrile (CD<sub>3</sub>CN) and pyridine for large crystals of SAPO-5 and GaAPO-5 is studied using FTIR microscopy with polarised IR radiation. From the analysis of the polarised adsorption bands it is concluded that the adsorbates are ordered in the molecular sieves at 373 K. The orientation of molecules interacting with Brönsted or Lewis acid sites and of physisorbed molecules are discussed. Benzene adsorbed at Brönsted sites is oriented with the aromatic ring parallel to the crystallographic <em>c</em>-axis of the molecular sieve, whereas physisorbed benzene is oriented with the aromatic ring parallel to the crystallographic <em>a,b</em>plane. Acetonitrile can adsorb on top of the Brönsted sites, resulting in an orientation with the CN-axis in the a,bplane. Physisorbed acetonitrile has the CN-axis parallel to the <em>c</em>-axis. Pyridinium ions have their aromatic rings parallel to the <em>a,b</em>-plane. Pyridine molecules at Lewis sites are oriented parallel to the <em>a,b</em>-plane in SAPO-5 and perpendicular to this plane in GaAPO-5. Physisorbed pyridine is oriented with its C<sub>2</sub>-axis parallel to the <em>c</em>-axis.</p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 1","pages":"Pages 95-109"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(96)00126-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74917678","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: 15

Room-temperature synthesis of silicate mesoporous MCM-41-type materials: influence of the synthesis pH on the porosity of the materials obtained 室温合成硅酸盐介孔mcm -41型材料:合成pH对所得材料孔隙率的影响

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(97)00003-5

A.C. Voegtlin , A. Matijasic , J. Patarin , C. Sauerland , Y. Grillet , L. Huve

{"title":"Room-temperature synthesis of silicate mesoporous MCM-41-type materials: influence of the synthesis pH on the porosity of the materials obtained","authors":"A.C. Voegtlin , A. Matijasic , J. Patarin , C. Sauerland , Y. Grillet , L. Huve","doi":"10.1016/S0927-6513(97)00003-5","DOIUrl":"10.1016/S0927-6513(97)00003-5","url":null,"abstract":"<div><p>Pure silica MCM-41 materials were synthesized at room temperature at different pH values ranging from 8.5 to 12. The solids were characterized by XRD, <sup>29</sup>Si-MAS-NMR spectroscopy and N<sub>2</sub> and Ar adsorption measurements. When the synthesis pH is too high, the degree of polycondensation of the silicate species is too low and, after removal of the organic species by calcination, amorphization occurs. For an intermediate pH value (11), the N<sub>2</sub> and Ar adsorption isotherms at 77 K, determined on the corresponding solid, are ‘type I-b like’ and are characteristic of the presence of primary and secondary micropores (<em>d</em><2 nm). At a low pH value (8.5), a typical MCM-41 material with a mesopore diameter of ~2.6nm is obtained. The adsorption isotherms are of type IV. The influence of the thermal treatment on the as-synthesized samples was studied, and an effect was observed in the material containing micropores. Whereas a short calcination time at 873 K leads to a decrease in the intensity of the XRD peaks, a prolonged calcination time at this temperature leads to an improvement in the degree of organization and to an increase in the total microporous volume of about 18%. This increase can be explained by the greater homogeneity of the micropore surface after such a thermal treatment.</p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 1","pages":"Pages 137-147"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00003-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89539265","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: 102

Effect of delayed neutralization on the synthesis of mesoporous MCM-41 molecular sieves 延迟中和对介孔MCM-41分子筛合成的影响

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00125-3

Hong-Ping Lin, Soofin Cheng, Chung-Yuan Mou

引用次数: 96

Characterization and catalytic activity of the AlMCM-41 prepared by a method of gel equilibrium adjustment 凝胶平衡调节法制备的AlMCM-41的表征及催化活性

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(97)00004-7

Jong-Ho Kim , Masahisa Tanabe, Miki Niwa

引用次数: 37

Synthesis, characterization and catalytic activity of SAPO-34 obtained with piperidine as templating agent 以哌替啶为模板剂制备SAPO-34的合成、表征及催化活性

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00107-1

Emil Dumitriu , Abdelkrim Azzouz , Vasile Hulea , Doina Lutic , Henri Kessler

引用次数: 74

Monolithic periodic mesoporous silica gels 单片周期性介孔硅胶

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00105-8

Mark T. Anderson, James E. Martin, Judy G. Odinek, Paula P. Newcomer, Jess P. Wilcoxon

{"title":"Monolithic periodic mesoporous silica gels","authors":"Mark T. Anderson, James E. Martin, Judy G. Odinek, Paula P. Newcomer, Jess P. Wilcoxon","doi":"10.1016/S0927-6513(96)00105-8","DOIUrl":"10.1016/S0927-6513(96)00105-8","url":null,"abstract":"<div><p>We have synthesized monolithic, surfactant-templated particulate gels that have pore volumes and surface areas comparable to silica xerogels and aerogels. The gels have a complex microstructure with micro-, meso- and macroscopic features that emerge over five orders of magnitude in length (1) amorphous silica walls (characterized by a broad distribution of Si-Si spacings of ≈0.4 nm), (2) periodic hexagonal arrays of 1-d channels within each particle (≈3 nm channel diameter), (3) a feature in the gas adsorption measurements that indicates a second class of ≈10–50 nm diameter mesopores, (4) particles that are ≈ 150 to ≈500 nm in diameter, (5) interparticle pores that are on the order of the particle size, and (6) fractal domains larger than the particle size (>10 000nm). The microstructure can be controlled by the varying the initial silica content, the template size, the drying conditions, or the calcination conditions. The wet gel monoliths exhibit calculated densities as low as ≈0.02 g/cm<sup>3</sup>; the dried and calcined gels have bulk densities that range from 0.3 to 0.5 g/cm<sup>3</sup>. The materials possess large interparticle (1.1–2.2 cm<sup>3</sup>/g) and intraparticle (0.3–0.6 cm<sup>3</sup>/g) porosities.</p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 1","pages":"Pages 13-24"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(96)00105-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77901985","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: 32

Physical studies of MoO3 catalysts on silica and carbon supports 二氧化硅和碳载体上MoO3催化剂的物理研究

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00127-7

Russell S. Drago, Vaneica Young, Nicholas Kob, David J. Singh, Gerald C. Grunewald

引用次数: 4

The characterization of Co(saloph) complexes encapsulated into VPI-5 and AlPO4-8 VPI-5和AlPO4-8包封Co(saloph)配合物的表征

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00121-6

Man-Hyoung Ryoo, Hakze Chon

引用次数: 4

Use of organic media to modify the surface and porosity properties of hydrotalcite-like compounds 利用有机介质修饰类水滑石化合物的表面和孔隙特性

Microporous Materials Pub Date : 1997-06-01 DOI: 10.1016/S0927-6513(96)00123-X

François Malherbe, Claude Forano, Jean-Pierre Besse

{"title":"Use of organic media to modify the surface and porosity properties of hydrotalcite-like compounds","authors":"François Malherbe, Claude Forano, Jean-Pierre Besse","doi":"10.1016/S0927-6513(96)00123-X","DOIUrl":"10.1016/S0927-6513(96)00123-X","url":null,"abstract":"<div><p>In this paper we have focused on the surface and porosity properties of [Mg-Al-CO<sub>3</sub>] and [Mg-Al-Cl] obtained by the coprecipitation method. Different synthetic routes are used as well as post-synthesis treatments in order to measure how far textural modifications can be induced in these materials. For example, by performing the direct synthesis of [Mg-Al-CO<sub>3</sub>] in mixtures composed of water and an organic solvent, or by regenerating calcined samples in similar mixtures, the surface areas, pore volumes and pore sizes are shown to be greatly affected by some solvents: synthesis in ethylene glycol causes an increase of 81% in the surface area, while in glycerol it results in the induction of microporosity (30%). On the other hand, we have also investigated the influence of these organic solvents on the textural properties during anion exchange reactions. Through analysis of their BET nitrogen adsorption/desorption isotherms, unpillared [Mg-Al-CO<sub>3</sub>] proved to be mostly mesoporous, while [Mg-Al] hydrotalcite pillared with hexacyanoferrate (III) exhibited high microporosity, this characteristic being greatly influenced when the exchange reactions were carried out in organic media. SEM images provided evidence of the microtextural modifications undergone by the products throughout these different treatments.</p></div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 1","pages":"Pages 67-84"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(96)00123-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79326981","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: 58