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Discussions of The Faraday Society最新文献

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Catalytic and inhibitory effects of metal chelates in autoxidation reaction 金属螯合物在自氧化反应中的催化和抑制作用
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600202
C. Copping, N. Uri
{"title":"Catalytic and inhibitory effects of metal chelates in autoxidation reaction","authors":"C. Copping, N. Uri","doi":"10.1039/DF9684600202","DOIUrl":"https://doi.org/10.1039/DF9684600202","url":null,"abstract":"Certain aspects of catalyst-inhibitor conversion with bis(N-butylsalicylaldimino)cobalt(II) were further examined: they include variations in oxygen partial pressure, hydrocarbon substrate and solvent environment. The decrease of autoxidation rates with increasing polarity of environment, which is in contrast to AIBN-initiated autoxidation, was particularly noteworthy. Catalytic and inhibitory effects of α-dithiodiketone chelates were studied in detail: they included NiS4C4Ph4, PdS4C4Ph4, PtS4C4Ph4, CoS4C4Ph4. PBu3 and similar cobalt chelates. They were shown to have catalytic activity as hydroperoxide decomposers of unprecedented magnitude. One mole of metal chelate decomposed catalytically at least 1000 moles of hydroperoxide and there was no evidence of free radical intermediates. These compounds were also free radical acceptors and were generally autoxidation inhibitors rather than catalysts at any concentration.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"7 1","pages":"202-212"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73254072","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: 17
Catalysis of some hydrogen transfer reactions by complexes of rhodium(III) and of ruthenium(II) 铑(III)和钌(II)配合物催化氢转移反应的研究
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600037
B. Hudson, P. Taylor, D. Webster, P. Wells
{"title":"Catalysis of some hydrogen transfer reactions by complexes of rhodium(III) and of ruthenium(II)","authors":"B. Hudson, P. Taylor, D. Webster, P. Wells","doi":"10.1039/DF9684600037","DOIUrl":"https://doi.org/10.1039/DF9684600037","url":null,"abstract":"At 50°C, isomerization of pent-1-ene is catalyzed by solutions of (i), Cl3(Ph3P)3Rh(III) in chloroform, in chloroform + alcohol mixtures, and in benzene, (ii), α-, and β-HCl2(Ph3P)3Rh(III) in benzene, and (iii), HCl(Ph3P)3Ru(II) in benzene. Cl2(Ph3P)3Ru(II) in benzene shows low activity. Characteristics of conversion-time curves are reported for each system. Whether or not reactions showed induction periods depended upon the nature of the complex, solvent composition, and the length of time for which solutions were allowed to stand before the addition of pent-1-ene. Some systems were very selective for the formation of pent-2-ene in the cis-form (cis : trans ∼18 : 1), whereas others were not (cis : trans ∼1.5 : 1). Cis-trans isomerization of the pent-2-ene was very slow compared to the rate of conversion of pent-1-ene to pent-2-ene, except when the catalytic solutions consisted of Cl3(Ph3P)3Rh(III) dissolved in CHCl3+C2H5OH mixtures which contained a high proportion of ethanol.There is evidence that the catalytic species are formed by solvolysis of the original complexes. Isotopic tracer studies show that, when methanol is present, catalyzed hydrogen-atom exchange occurs between olefin and methanol. Catalysis by rhodium complexes is facilitated if the complex contains a hydrogen ligand, and moreover the stereochemistry of the hydrido-complex appears to be important. Two ruthenium complexes, Cl2(Ph3P)3Ru(II), HCl(Ph3P)3Ru(II), have been examined to establish whether a “vacant ligand site” constitutes a useful feature of the original complex.Reactions of ethylene, particularly of trans-dideuteroethylene, with solutions of these complexes at 50°C have been investigated; isotope redistribution shows that reaction proceeds via ethyl intermediates. This supports the proposal that pentene isomerization occurs via pentyl intermediates and that the catalytic species in solution are hydrides.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"10 1","pages":"37-47"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81260454","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: 15
Electrode reactions of organic compounds. General introduction 有机化合物的电极反应。总体介绍
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684500007
R. Marcus
{"title":"Electrode reactions of organic compounds. General introduction","authors":"R. Marcus","doi":"10.1039/DF9684500007","DOIUrl":"https://doi.org/10.1039/DF9684500007","url":null,"abstract":"The last Faraday Society Discussions on Electrode Processes were held in 1947 and marked the onset of an extensive fruitful post-war development of fast reaction techniques in electrochemistry. Considerable information has since been obtained on rate constants of simple inorganic electron transfers, paralleling a similar development in homogeneous reactions, and on electron transfer theory. A theoretically-based relation exists between the two areas. It has often been noted that the Faraday Society Discussions have marked a turning point in a field. The area of organic reactions at electrodes has been somewhat on the periphery of the field of organic chemistry, its relation to the subject of metal-catalyzed organic syntheses notwithstanding. The papers of the present Discussions illustrate, perhaps for the first time as a body, the rich variety of studies in the present field and a role for current organic concepts.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"2 4","pages":"7-13"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91512827","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
Autoxidation of p-toluic acid catalyzed by cobalt bromide 溴化钴催化对甲苯的自氧化反应
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600164
C. Bawn, T. Wright
{"title":"Autoxidation of p-toluic acid catalyzed by cobalt bromide","authors":"C. Bawn, T. Wright","doi":"10.1039/DF9684600164","DOIUrl":"https://doi.org/10.1039/DF9684600164","url":null,"abstract":"The liquid-phase autoxidation of p-xylene proceeds with comparative ease in the presence of cobalt or manganese salts at 100–130°C to p-toluic acid. The oxidation of p-xylene to terephthalic acid in high yield may be achieved by using the cobalt or manganese salt in combination with an inorganic bromide. The present study, which was directed towards the elucidation of the latter reaction, was confined to the second part of the reaction, namely, the oxidation of p-toluic acid catalyzed by cobalt bromide. The reaction was observed to occur in glacial acetic acid at 90°C in two well-defined stages each of which was investigated. The first stage involved catalysis by both cobalt and bromide and during this phase of the oxidation bromide was present in the ionic form. The rate was proportional to the [cobalt][bromide] and independent of the substrate concentration above a limiting value and of the oxygen pressure in the range 2–32 cm Hg. At the onset of the second stage of the reaction the bromide ion was absent and the reaction was catalyzed by cobalt salt and p-bromomethyl benzoic acid. The principal intermediate in both stages was terephthaldehydic acid. Initiation occurred by the formation of atomic bromine either by direct electron transfer between cobaltic and bromide ions or by reaction of hydroperoxides with Br– or HBr. The aldehydic intermediate and final acid were formed from peroxidic intermediates.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"1 1","pages":"164-172"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83113874","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
Effect of current pulsing of current efficiencies of the Brown-Walker and Kolbe electrosyntheses 电流脉冲对Brown-Walker和Kolbe电合成电流效率的影响
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684500261
A. Hickling, R. Wilkins
{"title":"Effect of current pulsing of current efficiencies of the Brown-Walker and Kolbe electrosyntheses","authors":"A. Hickling, R. Wilkins","doi":"10.1039/DF9684500261","DOIUrl":"https://doi.org/10.1039/DF9684500261","url":null,"abstract":"The anodic reactions in the electrolysis of aqueous potassium ethyl malonate solutions and acetate solutions using galvanostatic square pulses have been investigated. When unidirectional pulses alone are employed the current efficiencies of the dimerization reactions leading to diethyl succinate and ethane respectively are nearly the same as in continuous d.c. electrolysis, independent of the frequency of pulsing. If, however, a small reverse current is passed between anodic pulses, there now appears a sharply defined minimum in the current efficiency against frequency curve at a characteristic frequency. This appears to arise from the passage in the cathodic direction of a critical quantity of electricity which serves to destroy the electrode conditions necessary for dimer production and to permit oxygen evolution to become an effective competitive reaction. Electrode potential changes during pulsing have been studied oscillographically, and these observations, combined with the current efficiency measurements, clarify the processes occurring initially at the anode surface which lead to dimer production.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"14 1","pages":"261-268"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88773861","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
Roles of cobaltic salts as catalysts of oxidation 钴盐作为氧化催化剂的作用
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600158
W. Waters
{"title":"Roles of cobaltic salts as catalysts of oxidation","authors":"W. Waters","doi":"10.1039/DF9684600158","DOIUrl":"https://doi.org/10.1039/DF9684600158","url":null,"abstract":"Cobalt salts are usually held to catalyze autoxidation by decomposing hydroperoxides by reactions (i) and (ii): the latter may be questioned and (iii) is an alternative. Evidence showing that cobaltic salts of carboxylic acids decompose to alkyl radicals is summarized. The reaction (iv) is equivalent to (iii) as a catalytic process. Cobaltic ions attack unsaturated acids mainly at the double bond: this too may be important in relation to autoxidation. CoII+ RO2H → CoIII+ RO·+(OH)–(i), CoIII+ RO2H → CoII+ RO2·+ H+(ii), CoIII+ RH → CoII+ R·+ H+(iii), R—CO—O—CoIII→ R·+ CO2+ CoII(iv)","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"336 2","pages":"158-163"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91477415","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: 14
Anodic oxidation under pulse conditions 脉冲条件下的阳极氧化
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684500254
M. Fleischmann, F. Goodridge
{"title":"Anodic oxidation under pulse conditions","authors":"M. Fleischmann, F. Goodridge","doi":"10.1039/DF9684500254","DOIUrl":"https://doi.org/10.1039/DF9684500254","url":null,"abstract":"The investigation of the Kolbe and Hofer-Moest reaction by a non-steady state method of applying a sequence of square-wave pulses to the working electrode is discussed. This technique permits the measurement of the formation of all the products of the reaction as a function of time, and allows a more searching evaluation of the reaction mechanisms than steady-state methods alone.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"60 1","pages":"254-260"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91009320","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
Catalysis by cobalto-cyano complexes in non-aqueous solvents 非水溶剂中钴氰配合物的催化作用
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600110
G. Pregaglia, D. Morelli, F. Conti, G. Gregorio, R. Ugo
{"title":"Catalysis by cobalto-cyano complexes in non-aqueous solvents","authors":"G. Pregaglia, D. Morelli, F. Conti, G. Gregorio, R. Ugo","doi":"10.1039/DF9684600110","DOIUrl":"https://doi.org/10.1039/DF9684600110","url":null,"abstract":"The chemistry and catalytic properties of cyano cobaltate (II) anion in non-aqueous solvents such as ethanol or acetic acid have been investigated. In ethanol the hydrogenation catalysis proceeds without the “ageing process” which occurs in water. The rate of hydrogen absorption by [Co(CN)5]3– is slow in anhydrous solvents and increases by increasing the water concentration. The selective hydrogenation, in ethanol, of cyclopentadiene and related dienic substrates has been investigated. The oxidative properties towards olefins of the hydroperoxide [Co(CN)5OOH]3– have been studied in water and in acetic acid.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"26 1","pages":"110-121"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73453403","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
Steric effects and the electrochemistry of phenyl-substituted anthracenes and related compounds 苯基取代蒽及其相关化合物的位阻效应和电化学
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684500167
A. Bard, K. Santhanam, J. T. Maloy, John Phelps, L. O. Wheeler
{"title":"Steric effects and the electrochemistry of phenyl-substituted anthracenes and related compounds","authors":"A. Bard, K. Santhanam, J. T. Maloy, John Phelps, L. O. Wheeler","doi":"10.1039/DF9684500167","DOIUrl":"https://doi.org/10.1039/DF9684500167","url":null,"abstract":"The reduction and oxidation potentials of a series of phenylsubstituted anthracenes (9-, 9,10-, 1,9-, 1,10-, 1-, and 2-) and rubrene were determined by polarographic and cyclic voltammetric techniques. These potentials correlate well with those predicted by molecular orbital calculations, based on parameters obtained from the electron spin resonance spectra of the corresponding radical ions. These results lead to the conclusion that structural information, such as the angle between the phenyl substituent and the anthracene nucleus, can be obtained from electrochemical measurements. The mechanism of the protonation reaction following the electron transfer steps is shown to depend upon the electron density distribution and positions of substitution in the radical ions.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"16 1","pages":"167-174"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87042777","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: 15
Oxidation of olefins by palladium salts in non-aqueous solvents 非水溶剂中钯盐对烯烃的氧化
Discussions of The Faraday Society Pub Date : 1968-01-01 DOI: 10.1039/DF9684600098
D. Clark, P. Hayden, R. Smith
{"title":"Oxidation of olefins by palladium salts in non-aqueous solvents","authors":"D. Clark, P. Hayden, R. Smith","doi":"10.1039/DF9684600098","DOIUrl":"https://doi.org/10.1039/DF9684600098","url":null,"abstract":"Ethylene and propylene have been oxidized in acetic acid to mixtures of saturated and unsaturated esters and carbonyl compounds. The reactions are catalyzed by combinations of palladium and copper salts. Separate reactions induced by Pd(II) alone and by Pd(II) and Cu(II) together have been kinetically distinguished. In oxidations of prophlene and octene by palladous acetate, the importance of the concentration of lithium acetate and of N,N-dimethylacetamide in promoting the synthesis of allylic esters has been described.","PeriodicalId":11262,"journal":{"name":"Discussions of The Faraday Society","volume":"123 3 1","pages":"98-109"},"PeriodicalIF":0.0,"publicationDate":"1968-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89414698","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: 11
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