Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80018-R
G. Edwin Vrieland *, P. Govind Menon
{"title":"Nature of the catalytically active carbonaceous sites for the oxydehydrogenation of ethylbenzene to styrene","authors":"G. Edwin Vrieland *, P. Govind Menon","doi":"10.1016/0166-9834(91)80018-R","DOIUrl":"10.1016/0166-9834(91)80018-R","url":null,"abstract":"<div><p>Over the past two decades work has appeared in several different laboratories describing a group of catalysts, such as aluminas and various metal phosphates, which are very selective for the oxydehydrogenation of ethylbenzene to styrene. Evidence has accumulated that the active site for these catalysts is actually a carbonaceous layer which is initially deposited on the surface. Carbon itself has shown significant activity and selectivity for this reaction. The history of this development and the various kinds of evidence which support the role of an active carbon overlayer are reviewed.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 1-8"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80018-R","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83792978","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}
Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80025-R
H. Curry-Hyde, M. Wainwright, D. Young
{"title":"Improvements to Raney copper methanol synthesis catalysts through zinc impregnation: I. Electron microprobe analysis","authors":"H. Curry-Hyde, M. Wainwright, D. Young","doi":"10.1016/0166-9834(91)80025-R","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80025-R","url":null,"abstract":"","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"11 1","pages":"75-88"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79300698","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}
Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80032-R
Claudine Dorémieux-Morin *, Claudine Martin, Jean-Marie Brégeault, Jacques Fraissard
{"title":"Multinuclear high-resolution solid-state nuclear magnetic resonance studies of amorphous silica-aluminas","authors":"Claudine Dorémieux-Morin *, Claudine Martin, Jean-Marie Brégeault, Jacques Fraissard","doi":"10.1016/0166-9834(91)80032-R","DOIUrl":"10.1016/0166-9834(91)80032-R","url":null,"abstract":"<div><p>Commercial silica-aluminas contain aluminium atoms tetra- and hexacoordinated to oxygen. After dehydration at 1 Pa at temperatures above 370 K, their<sup>1</sup>H MAS NMR spectra show silanol groups and OH groups bonded to aluminium atoms but no acidic bridging OH groups. Spectra of samples dehydrated at lower temperature give clear evidence for such acidic OH groups.<sup>29</sup>Si MAS and CP-MAS NMR spectra of silica-aluminas with low silica concentration show mainly SiO<sub>4</sub> tetrahedra bonded to four others and silicon atoms, bonded to OH groups, whose<sup>29</sup>Si chemical shift is upfield of that generally attributed to terminal SiOH or geminal Si(OH)<sub>2</sub>. The environment of SiO<sub>4</sub> tetrahedra in the sample with SiO<sub>2</sub>:Al<sub>2</sub>O<sub>3</sub> = 75:25, prepared by coprecipitation, is random.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 149-161"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80032-R","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77274801","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}
Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80029-V
Mamoru Ai
{"title":"Formation of acrolein by the reaction of formaldehyde with ethanol","authors":"Mamoru Ai","doi":"10.1016/0166-9834(91)80029-V","DOIUrl":"10.1016/0166-9834(91)80029-V","url":null,"abstract":"<div><p>A mixture of formalin and ethanol was passed at 240 to 320°C over various metal oxides supported on silica gel and metal phosphates using nitrogen as the carrier gas. The main products were acrolein, acetaldehyde, methanol, and carbon dioxide. The highest yields of acrolein were obtained with the nickel phosphate and silica-supported tungsten, zinc, nickel, and magnesium oxides. The yield of acrolein, on ethanol basis, reached 40 to 52 mol-% with a formaldehyde-to-ethanol molar ratio of 2. The effects of the reaction variables on acrolein formation were studied using a nickel phosphate catalyst with a phosphorus-to-nickel atomic ratio of<em>2/3</em>. It was proposed that acrolein is formed by the aldol condensation of formaldehyde with acetaldehyde which is formed in the reaction of hydrogen transfer from ethanol to formaldehyde.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 123-132"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80029-V","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75717898","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}
{"title":"Effects of hydroxylation of a silica surface on the metal dispersion in supported platinum catalysts","authors":"Masahiko Arai *, Shi-Ling Guo, Yoshiyuki Nishiyama","doi":"10.1016/0166-9834(91)80031-Q","DOIUrl":"10.1016/0166-9834(91)80031-Q","url":null,"abstract":"<div><p>The influence of the surface hydroxyl groups of porous silica on the degree of platinum dispersion was studied using silica supports with the same surface area but with an increasing amount of these functional groups. The supports were prepared by immersing a calcined silica in water at 70°C for various periods of time. Platinum was deposited on the supports by wet impregnation with aqueous solutions of platinum tetraamine dichloride (PTD) and chloroplatinic acid (CPA). For catalysts with PTD reduced at 400°C, the degree of platinum dispersion indicated a maximum for a support whose surface was moderately hydroxylated. Such an effect was not observed for the catalysts reduced at the lower temperature of 330°C and for those with CPA. The surface hydroxyl groups affected the reduction of PTD and certain types of surface hydroxyl groups may be responsible for the effects observed.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 141-148"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80031-Q","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75986228","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}
Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80026-S
H. Curry-Hyde, M. Wainwright, D. Young
{"title":"Improvements to raney copper methanol synthesis catalysts through zinc impregnation: II. Surface area development","authors":"H. Curry-Hyde, M. Wainwright, D. Young","doi":"10.1016/0166-9834(91)80026-S","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80026-S","url":null,"abstract":"","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"19 1","pages":"89-94"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78510312","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}
Applied CatalysisPub Date : 1991-10-01DOI: 10.1016/0166-9834(91)80025-R
H. Edward Curry-Hyde *, Mark S. Wainwright, David J. Young
{"title":"Improvements to Raney copper methanol synthesis catalysts through zinc impregnation","authors":"H. Edward Curry-Hyde *, Mark S. Wainwright, David J. Young","doi":"10.1016/0166-9834(91)80025-R","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80025-R","url":null,"abstract":"<div><p>The specific activity of a Raney Cu-ZnO-Al<sub>2</sub>O<sub>3</sub> catalyst for methanol synthesis from carbon monoxide and carbon dioxide has been found to be related to the mass of zinc per unit total area of Raney catalyst surface. This correlation hag been found to be independent of the conditions used to leach the material, although the level of zinc was found to be strongly dependent on the leaching conditions. The mass of zinc oxide in the catalytic material produced by leaching a Cu-Al-Zn alloy pellet in sodium hydroxide has been found to decrease continuously from the highest level close to the alloy/catalyst interface to the lowest level at the outer edge of the leached pellet. By leaching the alloy in a zincate rich solution the ZnO concentration profile in the leached material Cu-Al-Zn alloys can be unproved. The resulting catalysts have significantly higher specific activity which shows a strong correlation to the mass of zinc per unit total surface area. The zincate leached materials were found to have total amounts of zinc similar to the hydroxide leached materials. However, the aluminium levels were significantly lower. The high specific activity was attributed to improved contact between the copper and the ZnO which is precipitated onto the copper surface. On the basis of these results it is suggested that the active sites for methanol synthesis are at the interface between the copper and the ZnO crystallites.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 75-88"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80025-R","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92108676","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}
{"title":"Liquid phase Fischer-Tropsch synthesis on manganese-promoted ultrafine particles of iron used as a catalyst","authors":"Hiroyuki Itoh, Shinichi Nagano, Tatsuo Urata, Eiichi Kikuchi *","doi":"10.1016/0166-9834(91)80021-N","DOIUrl":"10.1016/0166-9834(91)80021-N","url":null,"abstract":"<div><p>The catalytic properties of manganese-promoted ultrafine particles (UFP) of iron for liquid phase Fischer-Tropsch (FT) synthesis have been investigated. Manganese-promoted iron UFP catalysts were prepared by physically mixing iron UFP and manganese oxide or by liquid phase deposition of manganese on iron UFP. These catalysts were highly selective for alkene production. In particular, the selectivity to lower alkenes over catalysts prepared by liquid phase manganese deposition was enhanced by the addition of extremely small amounts of manganese (several percent of iron). These catalysts gave very high yields of lower alkenes.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"77 1","pages":"Pages 37-43"},"PeriodicalIF":0.0,"publicationDate":"1991-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80021-N","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76059101","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}