Journal of Molecular Catalysis Pub Date : 1994-12-15 DOI: 10.1016/0304-5102(94)00154-5

Luis M. Gandía, Mario Montes

{"title":"Effect of the reduction temperature on the selectivity of the high temperature reaction of acetone and hydrogen over alumina and titania supported nickel and cobalt catalysts","authors":"Luis M. Gandía, Mario Montes","doi":"10.1016/0304-5102(94)00154-5","DOIUrl":"10.1016/0304-5102(94)00154-5","url":null,"abstract":"<div>The high-temperature acetone hydrogenation at atmospheric pressure over alumina and titania-supported nickel and cobalt catalysts has been studied. The results obtained during characterization have shown that the preparation steps produced a significant metal—support interaction in the alumina-supported precursors. On the other hand, the high-temperature (500°C) reduced titania-supported catalysts showed catalytic properties which resemble in some aspects those ascribed to the SMSI state. An interesting effect of the previous H2 reduction temperature on the acetone hydrogenation selectivity has been found. 2-Propanol and methyl isobutyl ketone (MIBK) were the main reaction products. The MIBK selectivity of the alumina-supported catalysts decreased as the temperature of reduction was increased. However, whereas the low-temperature (300°C) reduced titania-supported catalysts did not give any MIBK, a remarkable activity to this product was developed when the temperature of reduction was increased to 500°C. The effect of the temperature of reduction on selectivity has been tentatively explained according to a general model which relates the activation of the carbonyl functional group with specific sites created at the metal—support interface under conditions favourable to the establishment of significant metal—support interactions.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 3","pages":"Pages 347-367"},"PeriodicalIF":0.0,"publicationDate":"1994-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)00154-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76667675","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: 39

Dehydrogenation of isopropyl alcohol over CoNi/Mg oxide catalysts CoNi/Mg氧化物催化剂上异丙醇脱氢研究

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87041-1

Samih A. Halawy, Mohamed A. Mohamed, Suzan F. Abd El-Hafez

{"title":"Dehydrogenation of isopropyl alcohol over CoNi/Mg oxide catalysts","authors":"Samih A. Halawy, Mohamed A. Mohamed, Suzan F. Abd El-Hafez","doi":"10.1016/S0304-5102(94)87041-1","DOIUrl":"10.1016/S0304-5102(94)87041-1","url":null,"abstract":"<div>Catalytic dehydrogenation of isopropyl alcohol was studied over Co3O4NiO/MgO catalysts containing 20 wt% of Co3O4 and NiO, or mixture of both oxides with different molar ratios. Catalysts were prepared from the corresponding nitrates (i.e. Co(NO3)2·6H2O and Ni(NO3)2·6H2O) and supported on MgO. Catalyst precursors were examined by TG, DTG and DTA, and were calcined between 500–700°C for 5 h in air. The surface area of these samples were calculated using the BET method. Those catalysts calcined at 500°C were characterized by XRD analysis. The amount of excess surface oxygen for these catalysts was calculated iodometrically. Basicity measurements were estimated by the adsorption of acidic molecules using pulse technique method. The vapour-phase dehydrogenation of isopropyl alcohol (IP), has been carried out over the catalysts calcined between 500–700°C. All catalysts showed 99.5% selectivity towards acetone formation. A correlation between the catalytic activity and the basicity of these catalysts has been made. The activation energy and the order of the dehydrogenation reaction of IP over some catalysts are given.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 2","pages":"Pages 191-201"},"PeriodicalIF":0.0,"publicationDate":"1994-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0304-5102(94)87041-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81581999","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: 8

Catalytic conversion of oxygen containing cyclic compounds. Part II. Cyclohexanone conversion on HZSM-5 zeolites 含氧环化合物的催化转化。第二部分。环己酮在HZSM-5分子筛上的转化

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87046-2

Libor Brabec, Jana Nováková, Ludmila Kubelková

{"title":"Catalytic conversion of oxygen containing cyclic compounds. Part II. Cyclohexanone conversion on HZSM-5 zeolites","authors":"Libor Brabec, Jana Nováková, Ludmila Kubelková","doi":"10.1016/S0304-5102(94)87046-2","DOIUrl":"https://doi.org/10.1016/S0304-5102(94)87046-2","url":null,"abstract":"<div>Low-pressure on-stream conversion of cyclohexanone (CHN) was studied over HZSM-5 zeolites with various Si/ Al ratios (different number of strong acid sites). Each conversion run was followed by thermal decomposition of surface species which also were investigated using FTIR spectroscopy. It was found that, below 300°C, surface complexes consisting predominantly of CHN were held in the zeolites. The release of products, consisting of dehydrated CHN (C6H8), substituted aromatics and olefins, began above 250°C. The latter two compounds were formed via intermediates most probably of the aldol type (however, the dimerized methylcyclopentadiene intermediate cannot be excluded). The CHN dehydration to C6H8 predominated at 480°C. The yield of all products increased with the increasing number of zeolite strong acid sites. Ammonia, co-fed or preadsorbed, reacted with CHN to surface imines which hindered all other CHN reactions. The imine was strongly held in zeolites and decomposed at about 450°C to gaseous C6H8 and ammonia. Methanol partially methylated the reaction products but did not affect the main reaction routes, monomolecular dehydration and secondary intermolecular reactions.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 2","pages":"Pages 243-253"},"PeriodicalIF":0.0,"publicationDate":"1994-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0304-5102(94)87046-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91622495","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: 5

Phosphorus-31 NMR spin lattice relaxation times as an indirect probe of adsorbed water in supported aqueous phase catalysts 磷-31核磁共振自旋晶格弛豫时间作为负载型水相催化剂中吸附水的间接探针

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87037-3

Barbara B. Bunn, Tamas Bartik , Berit Bartik , William R. Bebout, Thomas E. Glass, Brian E. Hanson

引用次数: 11

New hydroformylation rhodium catalysts with dithiolate chiral ligands 新型二硫代酸酯手性配体氢甲酰化铑催化剂

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87036-5

A.M. Masdeu, A. Orejón, A. Ruiz, S. Castillón, C. Claver

{"title":"New hydroformylation rhodium catalysts with dithiolate chiral ligands","authors":"A.M. Masdeu, A. Orejón, A. Ruiz, S. Castillón, C. Claver","doi":"10.1016/S0304-5102(94)87036-5","DOIUrl":"10.1016/S0304-5102(94)87036-5","url":null,"abstract":"<div>Asymmetric hydroformylation of styrene is performed using the bridge dithiolate chiral rhodium complexes [Rh2(μ-(−)-DIOS)(cod)2]n n=2 (1); and n=1 (2); ((−)-DIOS: 2,3-O-isopropylidene-1,4-dithiO-L-threitol and cod: 1,5-cyclooctadiene) as catalyst precursors. The catalytic system 1 provides high conversion in the corresponding aldehydes (100% at 30 bar, 65°C) with a selectivity in 2-phenylpropanal of 64%. Addition of PPh3 to the catalytic system 1 increases the selectivity in 2-phenylpropanal to 91 % in the same conditions. Although the ee's obtained using 1 were low (3–5%), the addition of a chiral phosphine, (+)-DIOP ((2S,3S)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis (diphenylphosphino)butane), improves the ee in (S)-2-phenylpropanal to 17%. However the addition of (−)-DIOP gives a lower ee (3% (S)). Comparative results were obtained using 2 as catalyst precursor indicating that similar species were formed during catalytic cycle.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"94 2","pages":"Pages 149-156"},"PeriodicalIF":0.0,"publicationDate":"1994-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0304-5102(94)87036-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76906676","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: 25

OMCOS 8 OMCOS 8

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87048-9

引用次数: 0

Palladium-based catalysts supported on oligomeric aramides. A TPR investigation 低聚芳烃负载钯基催化剂。TPR调查

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87042-X

Francesco Arena, Giampietro Cum, Raffaele Gallo, Adolfo Parmaliana

引用次数: 5

Study of the competition between disproportionation and oxidation of cyclohexene in the liquid phase over solid catalysts 环己烯液相歧化氧化与固体催化剂竞争的研究

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87040-3

Z. Cvengrošová, M. Hronec

引用次数: 3

Cleavage of active esters by functional thiol compounds: Acceleration and time-dependent effects induced by cationic surfactants 功能性硫醇化合物对活性酯的裂解:阳离子表面活性剂诱导的加速和时间依赖性效应

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/S0304-5102(94)87047-0

Noureddine Krati, Alain Brembilla, Pierre Lochon

引用次数: 2

Poisoning of iron catalyst by COS in syngas for Fischer—Tropsch synthesis 费托合成合成气中铁催化剂的COS中毒研究

Journal of Molecular Catalysis Pub Date : 1994-11-27 DOI: 10.1016/0304-5102(94)87035-7

Zhao-Tie Liu, Jing-Lai Zhou, Bi-Jiang Zhang

引用次数: 35

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