Microporous Materials最新文献_第8页

Synthesis of boron-beta zeolite from near-neutral fluoride-containing gels 用近中性含氟凝胶合成硼沸石

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00010-2

S. Kallus, J. Patarin, P. Caullet, A.C. Faust

{"title":"Synthesis of boron-beta zeolite from near-neutral fluoride-containing gels","authors":"S. Kallus, J. Patarin, P. Caullet, A.C. Faust","doi":"10.1016/S0927-6513(97)00010-2","DOIUrl":"10.1016/S0927-6513(97)00010-2","url":null,"abstract":"<div>A borosilicate beta zeolite was prepared from almost neutral fluoride aqueous gels in the presence of 1,4-diazabicyclo[2.2.2]octane and methylamine as the templates. The influence of several physical and chemical parameters was studied. In comparison with the (Si,Al) system, this (Si,B) system appears less ‘reactive’ with longer crystallization times. Moreover, the products obtained display a narrower range of compositions. Only boron-rich (Si/B=2) and fluoride-poor media (F/Si=2) led to well-crystallized samples of beta zeolite characterized by a Si/B molar ratio close to 14. The differences observed between the two systems might be related to a stronger complexation of boron by the fluoride anions. The crystallization of the boron zeolite beta occurs probably through condensation reactions after hydrolysis of fluoroborate (BF4−), hydroxyfluoroborate (BF3OH− and BF2(OH)2−) and fluorosilicate species. Zeolite beta was characterized by XRD, SEM, chemical analysis, thermal analysis and 11B, 19F and 13C MAS NMR spectroscopy. The latter technique shows that the as-made beta samples contain, beside the dabconium cation, a polymeric compound identified as polyethylene piperazine.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 181-188"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00010-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77637566","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: 12

What is the solubility of zeolite A? 沸石A的溶解度是多少?

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00007-2

J. Šefc̆ík, A.V. McCormick

引用次数: 13

Synthesis of titanium-containing MCM-41 含钛MCM-41的合成

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00016-3

K.A. Koyano, T. Tatsumi

引用次数: 116

Synthesis of mazzite-type zeolites in the presence of organic solvents: study of the structure directing role of p-dioxane 有机溶剂存在下马辉石型沸石的合成:对二氧六烷结构导向作用的研究

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00013-8

B. De Witte , J. Patarin , J.L. Guth , T. Cholley

{"title":"Synthesis of mazzite-type zeolites in the presence of organic solvents: study of the structure directing role of p-dioxane","authors":"B. De Witte , J. Patarin , J.L. Guth , T. Cholley","doi":"10.1016/S0927-6513(97)00013-8","DOIUrl":"10.1016/S0927-6513(97)00013-8","url":null,"abstract":"<div>Syntheses were performed in the system 10SiO2:1Al2O3:xNa2O:[y wt.%organic compound + (100-y)wt.%H2O] at 150°C. In the presence of dioxane, for Na2O contents between 2 and 3, primarily mazzite-type products were obtained with Si/Al ratios ranging from 3.3 to 4.1. The dioxane content (y=5–85) influences both the availability of the dioxane-Na+ complex, which is essential for MAZ crystallization, and the effective alkalinity. As such, well-crystallized MAZ samples with high and low Si/Al ratios could be obtained at low (y=5–10) and high dioxane content (y=85), respectively, while at intermediate content (y=50), denser phases crystallized. For Na2O contents lower than 2, sodalite phases were formed with the neutral dioxane molecule acting as a templating agent, while above 3, mainly gismondine and analcime were produced. For syntheses with high dioxane content, the cyclic ether was partially replaced by other organic solvents (ethers and alcohols) to study the effect of the solvent properties on zeolite crystallization. The solubility of the organic compound in the aqueous phase and its solvating properties toward anions and cations are of key importance with respect to the rate and the type of zeolite synthesis in organic medium.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 247-257"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00013-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90477420","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: 22

Preparation and characterization of porous carbon loaded with iron particles: a possible magnetic carrier of medical drugs 载铁颗粒多孔碳的制备与表征:一种可能的医药磁性载体

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00012-6

V.K. Imshennik , I.P. Suzdalev , O.N. Stavinskaya , N.I. Shklovskaya , V. Schünemann , A.X. Trautwein , H. Winkler

{"title":"Preparation and characterization of porous carbon loaded with iron particles: a possible magnetic carrier of medical drugs","authors":"V.K. Imshennik , I.P. Suzdalev , O.N. Stavinskaya , N.I. Shklovskaya , V. Schünemann , A.X. Trautwein , H. Winkler","doi":"10.1016/S0927-6513(97)00012-6","DOIUrl":"10.1016/S0927-6513(97)00012-6","url":null,"abstract":"<div>In order to design magnetic carriers for medical drugs, carbon-supported iron samples with an iron content of 23, 29 and 43 wt.% have been prepared by impregnation of synthetic carbon with aqueous solution of iron oxalate followed by calcination and by reduction in hydrogen. The samples obtained after reduction times of 15, 30, 45 and 60 min have been characterized by Mössbauer spectroscopy, X-ray diffraction (XRD), and magnetization as well as adsorption measurements. Analysis of the Mössbauer and XRD data shows the presence of both oxidic and metallic iron particles with sizes in the 3–30 nm range. The saturation magnetization of the carbon loaded with 23, 29, and 43 wt.% iron has been determined to be 20, 30 and 80 emu per gram of solid, respectively. The hydrogen treatment induces in addition an increase of the meso- and macropore volumes of the iron-loaded carbon by a factor of about 1.4 with respect to the unloaded carbon. This fact is shown to lead to a better adsorption capacity for macro-molecular drugs like streptomycin and vitamin B12.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 225-230"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00012-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81659574","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: 9

Ni-, Mg- and Co-containing hydrotalcite-like materials with a sheet-like morphology: synthesis and characterization 具有片状形貌的含Ni、Mg和co的类水滑石材料:合成和表征

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00006-0

C.P. Kelkar, A.A. Schutz

{"title":"Ni-, Mg- and Co-containing hydrotalcite-like materials with a sheet-like morphology: synthesis and characterization","authors":"C.P. Kelkar, A.A. Schutz","doi":"10.1016/S0927-6513(97)00006-0","DOIUrl":"10.1016/S0927-6513(97)00006-0","url":null,"abstract":"<div>A new synthesis of hydrotalcite-like materials having a composition [M2+1−xAl3+x](OH)2 × A−x × mH2O, where M2+ is magnesium, nickel or cobalt and A− is a monocarboxylic anion, is described. The synthesis involves reacting a source of the divalent cation with pseudoboehmite and a monocarboxylic acid in an aqueous slurry at 95°C for 6 h. The reactive source of magnesium is either magnesium oxide or hydroxide and the reactive source for nickel and cobalt are the respective hydroxides. This synthesis method results in the formation of hydrotalcites with a unique sheet-like morphology with the sheets having breadth to thickness ratio in excess of 100, in contrast to the previously known hexagonal hydrotalcites which have a breadth to thickness ratio between 5 and 10. The phrase ‘sheet-like’ in this work describes the macroscopic morphology of the hydrotalcite crystallites. A key finding was that the presence of monocarboxylic acid was necessary for the formation of sheet morphology. It was also demonstrated that sheet and hexagonal morphologies readily interconvert via a common mixed oxide postcursor.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 163-172"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00006-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75226253","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

A 28-year-old synthesis of micelle-templated mesoporous silica 胶束模板化介孔二氧化硅的合成

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00028-X

Francesco Di Renzo, Hélène Cambon, Roger Dutartre

引用次数: 127

Synthesis and characterisation of zeolites using saturated cyclic amines as structure-directing agents 以饱和环胺为结构导向剂的沸石合成与表征

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00005-9

H. Jongkind, K.P. Datema, S. Nabuurs, A. Seive, W.H.J. Stork

{"title":"Synthesis and characterisation of zeolites using saturated cyclic amines as structure-directing agents","authors":"H. Jongkind, K.P. Datema, S. Nabuurs, A. Seive, W.H.J. Stork","doi":"10.1016/S0927-6513(97)00005-9","DOIUrl":"10.1016/S0927-6513(97)00005-9","url":null,"abstract":"<div>A synthesis route to obtain high-silica MOR using cyclic amines as structure-directing agents is described. As far as we know, the use of these structure-directing agents for the synthesis of high silica MOR is not described elsewhere.The pore size of the synthesised products (zeolite MOR, FER and mixtures of zeolite MOR and FER), was related to the ring size of the organic structure-directing agent in the reaction mixture. Various saturated cyclic amines were used. Pure high-silica MOR of high crystallinity was obtained via direct synthesis using hexa- and heptamethyleneimine. In addition, high-silica FER was prepared among others with pyrrolidine. A mixture of MOR and FER was synthesised in the presence of piperidine. The materials were characterised and the catalytic performance of the high silica MOR was evaluated.Catalysts prepared with direct synthesis of high-silica MOR as base material were active in the isomerisation of pentane and hexane. Presumably the direct-synthesis high-silica MOR samples were somewhat less active than conventional MOR (dealuminated by leaching to the same Si/Al ratio SAR), because of a lower accessibility of acid sites. The lower accessibility of the direct synthesis mordenite may be due to amorphous material. Other explanations are that extra-framework aluminum species were formed during calcination and preferential aluminium siting in these MOR crystals.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 149-161"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00005-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77710928","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: 26

Crown-ether mediated synthesis of FAU- and EMT-type zeolites in the presence of phosphate anions: study of the incorporation of gallium 磷酸阴离子存在下冠醚介导FAU型和emt型沸石的合成:镓掺入的研究

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00009-6

B. De Witte , J. Patarin , T. Cholley

引用次数: 3

Characterisation studies on the new microporous aluminium-containing ETS-10 molecular sieve used for processing larger molecules 用于处理大分子的新型微孔含铝分子筛ETS-10的表征研究

Microporous Materials Pub Date : 1997-07-01 DOI: 10.1016/S0927-6513(97)00011-4

Armin Liepold , Klaus Roos , Wladimir Reschetilowski , Zhi Lin , Joao Rocha , Andreas Philippou , Michael W. Anderson

{"title":"Characterisation studies on the new microporous aluminium-containing ETS-10 molecular sieve used for processing larger molecules","authors":"Armin Liepold , Klaus Roos , Wladimir Reschetilowski , Zhi Lin , Joao Rocha , Andreas Philippou , Michael W. Anderson","doi":"10.1016/S0927-6513(97)00011-4","DOIUrl":"10.1016/S0927-6513(97)00011-4","url":null,"abstract":"<div>This study reports on the physico-chemical characterisation of an aluminium-containing microporous titanosilicate ETS-10 material in its protonic form in connection with catalytic testing. 27Al MAS NMR spectra reveal the successful incorporation of aluminium into the lattice structure. XRD patterns indicate that the investigated ETAS-10 material in its protonic form is relatively stable thermally, an indispensable requirement for the application as an industrial catalyst material. Nevertheless, for all samples, except parent ETAS-10, XRD and 29Si MAS NMR measurements indicate that an increasing amount of amorphous silica is present. Acidity investigations with combined FT-IR spectroscopy and temperature-programmed ammonia desorption and with 1H MAS NMR revealed that dehydroxylation of bridging hydroxyl groups, which are assumed to be of the type Ti-(OH)-Si, occur between 350 and 550°C. An increase in both the number and strength of catalytically active bridging hydroxyl groups seems to be limited by a conventional protonic ion-exchange. The acid properties corroborate excellently with the catalytic activity and selectivity in n-hexadecane and 1,3,5-triisopropylbenzene cracking. The results show that electron acceptor sites, which may originate from titaniumoxide impurities or defect sites especially in titanium octahedra, could be involved in the catalytic reactions forming radical precursors.</div>","PeriodicalId":100926,"journal":{"name":"Microporous Materials","volume":"10 4","pages":"Pages 211-224"},"PeriodicalIF":0.0,"publicationDate":"1997-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0927-6513(97)00011-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78877115","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