Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)87001-2

J. Barrault, M. Blanchard, A. Derouault, M. Ksibi, M.I. Zaki

{"title":"Infrared observation of the chemical consequences of cobalt catalyst produced in mixed solutions of Al(Et)3 and Co(acac)2","authors":"J. Barrault, M. Blanchard, A. Derouault, M. Ksibi, M.I. Zaki","doi":"10.1016/0304-5102(94)87001-2","DOIUrl":"https://doi.org/10.1016/0304-5102(94)87001-2","url":null,"abstract":"<div>Cobalt catalysts obtained from the reduction of Co(acac)2 with Al(Et)3 have been studied by infrared spectroscopy (in the selective hydrogenation of multifunctional compounds). These solids prepared in situ were in suspension in a liquid mixture containing solvent and reagent. In order to obtain information on the preparation and the composition of the catalyst we carried out an FT-IR characterization using a special device warranting sample manipulation in air-free atmosphere. At room temperature there were instantaneous and reductive ligand-exchange between Al(Et)3 and Co(acac)2 and formation of Co0 particles, Co0 soluble complexes and Al(Et)2(acac). The multistep process may be initiated through the formation of a donor-acceptor complex ((acac)Co(acac)→Al(Et)3). The presence of CO in the gas phase (H2) when heating the reaction mixture up to 180°C enhances the reduction of cobalt and probes Co0 in different coordination symmetries. Some of the Co0 species could be surrounded with cobalt alkoxide species and aluminium acetylacetonate.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"93 3","pages":"Pages 289-304"},"PeriodicalIF":0.0,"publicationDate":"1994-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)87001-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91732203","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: 6

Global kinetics of the alkaline oxidative degradations of lactose 乳糖碱性氧化降解的整体动力学

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00122-7

H.E.J. Hendriks , B.F.M. Kuster, G.B. Marin

引用次数: 5

Stereoselective reduction of menthone with sodium dithionite in the presence of β-cyclodextrin 在β-环糊精存在下用二亚硫酸钠立体选择性还原薄荷酮

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00129-4

Ramaswamy Ravichandran, Soundar Divakar

引用次数: 6

Transition metal oxides as catalysts for the selective reduction of nitrobenzene 过渡金属氧化物作为硝基苯选择性还原催化剂的研究

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00121-9

A. Maltha, S.C. van Wermeskerken, B. Brunet, V. Ponec

引用次数: 11

Dark catalytic reduction of CO2 over Prussian blue-deposited TiO2 and the photo-reactivation of the catalyst 普鲁士蓝沉积TiO2上CO2的暗催化还原及催化剂的光活化

Journal of Molecular Catalysis Pub Date : 1994-10-27 DOI: 10.1016/0304-5102(94)00109-X

H. Uchida, T. Sasaki, K. Ogura

引用次数: 8

Oxidation of catechol with KMnO4 by using crown ethers as phase transfer catalysts 以冠醚为相转移催化剂，KMnO4氧化儿茶酚

Journal of Molecular Catalysis Pub Date : 1994-10-13 DOI: 10.1016/0304-5102(94)00074-3

Kazuyoshi Nakamura, Satoru Nishiyama, Shigeru Tsuruya, Mitsuo Masai

{"title":"Oxidation of catechol with KMnO4 by using crown ethers as phase transfer catalysts","authors":"Kazuyoshi Nakamura, Satoru Nishiyama, Shigeru Tsuruya, Mitsuo Masai","doi":"10.1016/0304-5102(94)00074-3","DOIUrl":"10.1016/0304-5102(94)00074-3","url":null,"abstract":"<div>The effect of crown ethers as phase transfer catalysts (PTC) was investigated in the liquid-phase oxidation of 3,5-di-tert-butylcatechol (3,5-DtBC) using potassium permanganate. Both the liquid—liquid (aqueous liquid layer including KMnO4/organic liquid layer including crown ether and 3,5-DtBC) and the solid—liquid (solid KMnO4/organic liquid layer including crown ether and 3,5-DtBC) systems were studied under mild reaction conditions. The oxidations of 3,5-DtBC in both systems were promoted by using crown ethers as PTCs. In the liquid—liquid system, the influence of organic solvents, acid additives and the type of crown ethers utilized were investigated. The oxidation rate of 3,5-DtBC was increased by using a solvent with a low polarity such as n-hexane and/or by adding an organic or inorganic acid to the system. Crown ethers which have a cavity that conforms to the radius of the K+ ion, and were more lipophilic such as dicyclohexano-18-crown-6 (DC18C6) also caused an increase in the oxidation rate. The rate-determining step is thought to be the oxidation reaction step in the organic phase, rather than the phase transfer step of the crown ether—KMnO4 complex. In the solid—liquid system, the influence of organic solvents and the type of crown ethers was investigated. The rate of 3,5-DtBC oxidation was increased by using a solvent with a high polarity such as chloroform. The complex stability between the crown ether and K+ was suggested to be one of the most important factors governing the oxidation rate in the solid—liquid system.</div>","PeriodicalId":16567,"journal":{"name":"Journal of Molecular Catalysis","volume":"93 2","pages":"Pages 195-210"},"PeriodicalIF":0.0,"publicationDate":"1994-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)00074-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83871813","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: 16

High resolution Auger electron spectroscopic study of the chemisorption and decomposition of benzene, cyclohexene and cyclohexane on a clean and carbided Fe(110) surface 高分辨率俄歇电子能谱研究了苯、环己烯和环己烷在清洁和碳化铁(110)表面上的化学吸附和分解

Journal of Molecular Catalysis Pub Date : 1994-10-13 DOI: 10.1016/0304-5102(94)00106-5

A.K. Bhattacharya

引用次数: 1

Homogeneous esterolytic catalysis of a polymer prepared by molecular imprinting of a transition state analogue 过渡态类似物分子印迹制备的聚合物的均相酯化催化

Journal of Molecular Catalysis Pub Date : 1994-10-13 DOI: 10.1016/0304-5102(94)00105-7

Katsutoshi Ohkubo , Yasuo Urata , Shogo Hirota , Yuhji Honda , Yu-ichi Fujishita , Takashi Sagawa

引用次数: 37

Acylation of phenol with acetic acid over a HZSM5 zeolite, reaction scheme 苯酚与乙酸在HZSM5沸石上的酰化反应方案

Journal of Molecular Catalysis Pub Date : 1994-10-13 DOI: 10.1016/0304-5102(94)00107-3

I. Neves , F. Jayat , P. Magnoux , G. Pérot , F.R. Ribeiro , M. Gubelmann , M. Guisnet

引用次数: 63

Polymerization of phenylacetylene by Lewis acid activated tungsten carbonyl complexes 路易斯酸活化钨羰基配合物聚合苯乙炔的研究

Journal of Molecular Catalysis Pub Date : 1994-10-13 DOI: 10.1016/0304-5102(94)00088-3

T. Szymańska-Buzar

引用次数: 28

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