{"title":"Stabilized tetragonal zirconium oxide as a support for catalysts Evolution of the texture and structure on calcination in static air","authors":"P.D.L. Mercera *, J.G. van Ommen, E.B.M. Doesburg, A.J. Burggraaf, J.R.H. Roes","doi":"10.1016/0166-9834(91)80090-J","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80090-J","url":null,"abstract":"<div><p>Single-phase tetragonal zirconium oxides have been made by the incorporation of 5.4 mol-% of Y<sup>3+</sup> or La<sup>3+</sup> in ZrO<sub>2</sub> to form solid solutions. The samples were prepared by controlled coprecipitation from aqueous solutions of the respective metal chlorides at room temperature and at a constant pH of 10, followed by calcination at 500°C (in the case of the Y<sup>3+</sup> -doped sample) or 600°C (in the case of the La<sup>3+</sup> -doped sample) to effectuate the crystallization into the tetragonal phase. The process of crystallization of the hydrous zirconia precursor was found to be retarded by the incorporation of Y<sup>3+</sup> or La<sup>3+</sup>, the latter giving the greater effect. Upon crystallization, stabilized tetragonal samples were obtained with high specific surface areas (<em>S</em><sub>BET</sub> ca. 88 m<sup>2</sup> g<sup>−1</sup> for both the samples) and well-developed mesoporous textures but without any microporosity. Both the Y<sup>3+</sup> - and the La<sup>3+</sup> -alloyed ZrO<sub>2</sub> samples were found to fully retain the tetragonal phase upon calcination over the entire range of temperatures studied (up to 900°C). The thermal stability of the texture of zirconia was found to be considerably improved, in comparison with the undoped monoclinic material, by the stabilization of the crystal structure in the defect tetragonal form. In particular, incorporation of 5.4 mol-% of La<sup>3+</sup> resulted in a support material which had a remarkable thermal stability. It is shown that the improvements in the thermal stability are derived from a strong inhibition of the processes of crystallite growth and the accompanying intercrystallite sintering and thus of the process of mass transport; the mass transport probably occurs by a mechanism of surface diffusion.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 79-96"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80090-J","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91642772","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80095-E
C.S. McKee
{"title":"Photochemistry of adsorbates on metals","authors":"C.S. McKee","doi":"10.1016/0166-9834(91)80095-E","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80095-E","url":null,"abstract":"","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages N3-N5"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80095-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91642775","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80089-F
G.E. Parris *, J.N. Armor
{"title":"Catalytic cracking of organic amides","authors":"G.E. Parris *, J.N. Armor","doi":"10.1016/0166-9834(91)80089-F","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80089-F","url":null,"abstract":"<div><p>Previously we described catalysts for the efficient cracking of ethylidene bis formamide to<em>N</em>-vinyl formamide. Surprisingly, non-acidic catalysts operate at lower temperatures than described earlier for less selective catalysts. This manuscript describes the extension of the catalytic technology to other amides. Data for a variety of different substituted amides is used to propose a mechanism for this cracking reaction. In addition a “vinyl cracking index” is proposed (based upon the relative conversion of an acetal vs. an ether over the same catalyst) which allows us to rank current catalysts and forecast new catalysts for the cracking of<em>N</em>-vinyl amides precursors.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 65-78"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80089-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91702045","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80092-B
C.U. Ingemar Odenbrand *, Pär L.T. Gabrielsson, Jan G.M. Brandin, Lars A.H. Andersson
{"title":"Effect of water vapor on the selectivity in the reduction of nitric oxide with ammonia over vanadia supported on silica-titania","authors":"C.U. Ingemar Odenbrand *, Pär L.T. Gabrielsson, Jan G.M. Brandin, Lars A.H. Andersson","doi":"10.1016/0166-9834(91)80092-B","DOIUrl":"10.1016/0166-9834(91)80092-B","url":null,"abstract":"<div><p>The effect of the presence of water vapor on the reduction of nitric oxide with ammonia was investigated using vanadia on SiO<sub>2</sub>-TiO<sub>2</sub> as a catalyst. The selectivity towards nitrogen is greatly increased upon addition of water. Repeated use at temperatures of 825 K causes sintering of the catalyst and loss of activity as well as selectivity towards nitrogen. The formation of nitrous oxide is preferentially taking place on large crystals of presumably reduced vanadia. Removal of these crystals results in a more selective catalyst.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 109-122"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80092-B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86745450","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80086-C
P. Schulz, M. Baerns
{"title":"Aromatization of ethane over gallium-promoted H-ZSM-5 catalysts","authors":"P. Schulz, M. Baerns","doi":"10.1016/0166-9834(91)80086-C","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80086-C","url":null,"abstract":"","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"101 1","pages":"15-29"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76269051","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80093-C
F. Noronha, M. Schmal, M. Primet, R. Fréty
{"title":"Characterization of palladium-copper bimetallic catalysts supported on silica and niobia","authors":"F. Noronha, M. Schmal, M. Primet, R. Fréty","doi":"10.1016/0166-9834(91)80093-C","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80093-C","url":null,"abstract":"","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"5 2","pages":"125-139"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91422899","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80086-C
Philippe Schulz, Manfred Baerns *
{"title":"Aromatization of ethane over gallium-promoted H-ZSM-5 catalysts","authors":"Philippe Schulz, Manfred Baerns *","doi":"10.1016/0166-9834(91)80086-C","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80086-C","url":null,"abstract":"<div><p>Ethane was partly converted to aromatics over gallium-promoted H-ZSM-5 catalysts having different Si/Al ratios (15,25,34,50,75 and 95) and gallium contents ranging from 1.5 to 6 wt.-%. Temperatures varied between 823 and 973 K; the ethane partial pressure was 80 kPa. A maximum aromatics selectivity of 57% was obtained for a gallium (3.1 wt.-% )/ZSM 5 (Si/Al = 15) catalyst at 873 K (ethane conversion: 28.2%;<em>W/F</em>= 19.2 g h mol<sup>−1</sup>). The method of catalyst preparation (incipient wetness impregnation or ion exchange) had no influence on catalyst activity and selectivity. Kinetic measurements indicated that ethane is dehydrogenated by both Ga<sub>2</sub>0<sub>3</sub> at the outside surface of the zeolite and by the acid centres of the H-ZSM-5 catalysts to ethylene; in a subsequent step the ethylene is oligomerized and cyclized in the channels of the zeolite. Aromatic hydrocarbons are formed after further dehydrogenation. Mainly benzene, toluene and xylenes were obtained.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 15-29"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80086-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91642773","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80093-C
Fabio B. Noronha, Martin Schmal *, Michel Primet, Roger Frety
{"title":"Characterization of palladium-copper bimetallic catalysts supported on silica and niobia","authors":"Fabio B. Noronha, Martin Schmal *, Michel Primet, Roger Frety","doi":"10.1016/0166-9834(91)80093-C","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80093-C","url":null,"abstract":"<div><p>Silica and niobia Pd-Cu supported bimetallic catalysts were characterized by temperature-programmed reduction (TPR), hydrogen chemisorption and infrared spectroscopy of adsorbed carbon monoxide. On catalysts reduced at 573 K, the metal-metal interaction was confirmed from the analysis of TPR profiles and the decreased capacity of hydrogen chemisorption with increasing copper content. After reduction at 773 K, the palladium/niobia catalyst displays a SMSI effect; however, the increase in copper content in the bimetallic catalyst led to a suppression of the SMSI.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 125-139"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80093-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91642774","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 : 1991-10-29DOI: 10.1016/0166-9834(91)80088-E
G.E. Parris *, J.N. Armor
{"title":"Catalytic cracking of organic amides","authors":"G.E. Parris *, J.N. Armor","doi":"10.1016/0166-9834(91)80088-E","DOIUrl":"https://doi.org/10.1016/0166-9834(91)80088-E","url":null,"abstract":"<div><p>The development of a new family of polymers with a reactive primary amine function [poly(vinyl amine)] has been delayed by the availability of a suitable monomer. Bis amides are attractive intermediates for the large scale synthesis of the monomer. Dramatically improved catalytic technology for cracking bis amides to vinyl amides in high yields is reported. This technology now offers an attractive route to vinylamide monomers which may be polymerized to produce amine functionalized polymers. The catalysts suitable for the cracking process are porous, hydrogen abstracting catalysts, such as activated carbon, magnesium oxide, silicon phosphate, strontium pyrophosphate, neutral or basic calcium hydroxyapatite, CuCrO<sub>2</sub> and La<sub>2</sub>O<sub>3</sub>. The catalytic cracking reaction is carried out at a temperature in the range of 200 to 350°C. The best product selectivities are obtained when the process is operated at a low partial pressure of the organic feed to ensure that gas phase is predominant.</p></div>","PeriodicalId":8091,"journal":{"name":"Applied Catalysis","volume":"78 1","pages":"Pages 45-64"},"PeriodicalIF":0.0,"publicationDate":"1991-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0166-9834(91)80088-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91702044","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}