Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87031-4

Makoto Toba , Fujio Mizukami , Shu-ichi Niwa , Tsuneji Sano , Kazuyuki Maeda , Arto Annila , Veikko Komppa

{"title":"The effect of preparation methods on the properties of zirconia/silicas","authors":"Makoto Toba , Fujio Mizukami , Shu-ichi Niwa , Tsuneji Sano , Kazuyuki Maeda , Arto Annila , Veikko Komppa","doi":"10.1016/0304-5102(94)87031-4","DOIUrl":"10.1016/0304-5102(94)87031-4","url":null,"abstract":"<div><p>Zirconia/silicas were prepared by three methods, namely complexing-agent assisted sol—gel, coprecipitation and hydrogel kneading. The relationship between the preparation methods and properties of the zirconia/silicas was investigated by X-ray powder diffraction, solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR), ammonia temperature-programmed desorption (TPD) and nitrogen adsorption. Among the three methods, the complexing-agent assisted sol—gel method gave the most homogeneous zirconia/silicas and the ZrOSi bond formation. The specific surface area of the zirconia/silicas depended on the complexing agents used in the preparations and the Zr/Si ratios. In contrast, the kneaded zirconia/silicas were relatively heterogeneous and their properties did not depend on the Zr/Si ratio. In the dependence of properties of zirconia/silicas on the Zr/Si ratio, the coprecipitation zirconia/silicas are intermediate between the complexing-agent assisted sol—gel and kneaded ones.</p></div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 1","pages":"Pages 85-96"},"PeriodicalIF":0.0,"publicationDate":"1994-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)87031-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89667743","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

Catalytic conversion of oxygen containing cyclic compounds. Part I. Cyclohexanol conversion over H[Al]ZSM-5 and H[B]ZSM-5 含氧环化合物的催化转化。第一部分:H[Al]ZSM-5和H[B]ZSM-5上环己醇的转化

Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87033-0

Libor Brabec, Jana Nováková, Ludmila Kubelková

{"title":"Catalytic conversion of oxygen containing cyclic compounds. Part I. Cyclohexanol conversion over H[Al]ZSM-5 and H[B]ZSM-5","authors":"Libor Brabec, Jana Nováková, Ludmila Kubelková","doi":"10.1016/0304-5102(94)87033-0","DOIUrl":"10.1016/0304-5102(94)87033-0","url":null,"abstract":"<div><p>Cyclohexanol (CHL) conversion was measured under low-pressure on-stream conditions on HZSM-5 zeolites and on H-boralite using small amounts of catalysts. Catalytic runs were followed by TPD of the surface species, which also were studied using FTIR spectroscopy. It was found that the individual reaction steps, low-temperature dehydration (yielding cyclohexene), skeletal isomerization (ring contraction to methylcyclopentene) and reactions involving H-transfer (formation of methylcyclopentane, substituted aromatics and simple olefins) were conditioned by the presence of strong acid sites whose number needed for these reactions increased from the dehydration to the H-transfer reactions. The CHL reaction was compared with the reactions of cyclohexene, and the effect of Lewis acid sites present in some cases together with the Brønsted sites was discussed. Ammonia was found to block the active centers, reduce the isomerization and especially the reactions involving H-transfer. Contrary to ammonia, methanol reacted with the CHL surface complexes yielding more substituted aromatics and more olefins than CHL or methanol alone (and/or simple sum of CHL and methanol products).</p></div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 1","pages":"Pages 117-130"},"PeriodicalIF":0.0,"publicationDate":"1994-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)87033-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76176351","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: 18

Hydrogenation of the aromatic rings of 2-ethylanthraquinone on palladium catalyst 钯催化剂上2-乙基蒽醌芳香环的加氢反应

Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87028-4

E. Santacesaria , M. Di Serio , R. Velotti , U. Leone

引用次数: 33

Hydroisomerization probe of the catalytic and structural behavior of iron—rhodium particles supported on refractory oxide supports 难熔氧化物载体上铁铑颗粒的催化和结构行为的加氢异构化探针

Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87032-2

Suzana M. da Silva, Jonathan Phillips

{"title":"Hydroisomerization probe of the catalytic and structural behavior of iron—rhodium particles supported on refractory oxide supports","authors":"Suzana M. da Silva, Jonathan Phillips","doi":"10.1016/0304-5102(94)87032-2","DOIUrl":"10.1016/0304-5102(94)87032-2","url":null,"abstract":"<div><p>In order to understand the role of metal—support interactions in determining the structure and catalytic chemistry of multimetallic catalysts, kinetic and calorimetric studies of FeRh particles supported on a number of refractory oxide supports were conducted. Kinetic studies (1-butene hydroisomerization) showed that selectivity and activity were influenced by a number of parameters, particularly support identity, but also reduction temperature, and time on stream. To explain the observed kinetics it is postulated: (i) catalysis takes place both at metal sites and at acid sites on the surface, and that the selectivity of each site type is very different, (ii) the presence of metal enhances the rate of reaction at the acid sites by providing hydrogen atoms via a spillover mechanism, (iii) the metal loses activity more rapidly than the acid sites and (iv) due to the relative strengths of iron and rhodium interactions with the support, rhodium is preferentially reduced. Microcalorimetric studies of the surface composition support the postulate that rhodium is preferentially reduced and found at the surface. In sum, this study clearly shows that the structural and hence catalytic behavior of refractory oxide supported FeRh is distinctly different than that observed for the same metals on a graphitic support, thus demonstrating the critical importance of metal—support interactions in determining the catalytic character of multimetallic particles.</p></div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 1","pages":"Pages 97-116"},"PeriodicalIF":0.0,"publicationDate":"1994-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)87032-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73854686","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

Aerobic epoxidation of olefins catalyzed by polymerizable β-ketoesterate complexes of iron(III), nickel(II) and cobalt(II) 铁(III)、镍(II)和钴(II)可聚合β-酮酯配合物催化烯烃有氧环氧化反应

Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87026-8

P. Mastrorilli, C.F. Nobile

引用次数: 22

Surface nonuniformity and kinetic insensitivity on heterogeneous catalysts 非均相催化剂的表面不均匀性和动力学不敏感性

Journal of Molecular Catalysis Pub Date : 1994-11-13 DOI: 10.1016/0304-5102(94)87029-2

V.T. Popa, E. Segal

引用次数: 3

Immobilization of lipase from Candida cylindracea on inorganic supports 圆柱假丝酵母脂肪酶在无机载体上的固定化研究

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00108-1

J.M. Moreno, J.V. Sinisterra

引用次数: 53

Hydroformylation of 1 -aryl- 1 -(2-pyridyl) ethenes catalyzed by rhodium complexes 铑配合物催化1 -芳基- 1 -(2-吡啶基)乙烯的氢甲酰化反应

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00110-3

Carlo Botteghi , Stefano Paganelli , Laura Bigini , Mauro Marchetti

引用次数: 12

Methylamine synthesis over solid acid catalysts: Reaction kinetic measurements 固体酸催化剂合成甲胺:反应动力学测量

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00118-9

D.T. Chen , L. Zhang , J.M. Kobe , Chen Yi , J.A. Dumesic

引用次数: 14

Catalytic oxidation of erythrosine by cobalt phthalocyanines 酞菁钴催化氧化红氨酸的研究

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00116-2

Toshiyuki Watanabe , Ronald D Archer

引用次数: 5

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