Nuclear magnetic resonance salt shifts have been determined for a wide range of electrolytes in water at 273 and 298 K. Salt shifts for alkali metal chlorides have also been determined at 313, 333 and 353 K. Two independent methods are discussed for assigning an absolute shift to the chloride ion. The absolute values so derived are used to set up scales of absolute ionic shifts, which are discussed in terms of ion-solvent interactions. Although we do not discount the possibility of long-range effects, we can explain our results by reference only to the primary solvation layers. The anion shifts were mainly dependent on the basicity of the anion, but various anomalous cases are discussed.
{"title":"Solvation spectra. Part 41.—Absolute proton magnetic resonance shifts for water protons induced by cations and anions in aqueous solutions","authors":"J. Davies, S. Ormondroyd, M. Symons","doi":"10.1039/TF9716703465","DOIUrl":"https://doi.org/10.1039/TF9716703465","url":null,"abstract":"Nuclear magnetic resonance salt shifts have been determined for a wide range of electrolytes in water at 273 and 298 K. Salt shifts for alkali metal chlorides have also been determined at 313, 333 and 353 K. Two independent methods are discussed for assigning an absolute shift to the chloride ion. The absolute values so derived are used to set up scales of absolute ionic shifts, which are discussed in terms of ion-solvent interactions. Although we do not discount the possibility of long-range effects, we can explain our results by reference only to the primary solvation layers. The anion shifts were mainly dependent on the basicity of the anion, but various anomalous cases are discussed.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"3465-3473"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716703465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57634883","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}
The dissolution into water of anhydrite and gypsum was studied at 25°C using a rotating disc of polycrystalline material, and the kinetics were followed with a calcium selective electrode. The dissolution rate of gypsum was transport controlled while that of anhydrite was intermediate between chemical and transport control.
{"title":"Dissolution rates of polycrystalline samples of gypsum and orthorhombic forms of calcium sulphate by a rotating disc method","authors":"A. Barton, N. M. Wilde","doi":"10.1039/TF9716703590","DOIUrl":"https://doi.org/10.1039/TF9716703590","url":null,"abstract":"The dissolution into water of anhydrite and gypsum was studied at 25°C using a rotating disc of polycrystalline material, and the kinetics were followed with a calcium selective electrode. The dissolution rate of gypsum was transport controlled while that of anhydrite was intermediate between chemical and transport control.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"3590-3597"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716703590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57673013","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}
Thermal methods were used to determine with high precision the solid-liquid phase equilibria diagram for the sodium-caesium system. The results differ greatly from those of earlier workers, especially near the eutectic composition, where differences in melting points as large as 35 K occur. Identification of the phases involved in the peritectic halt was not conclusive, but does support the proposal that the peritectic results from the formation of an Na2Cs intermetallic compound by a sluggish reaction.
{"title":"Solid-liquid phase equilibrium in the sodium-caesium alloy system","authors":"J. Ott, J. Goates, D. E. Oyler","doi":"10.1039/TF9716700031","DOIUrl":"https://doi.org/10.1039/TF9716700031","url":null,"abstract":"Thermal methods were used to determine with high precision the solid-liquid phase equilibria diagram for the sodium-caesium system. The results differ greatly from those of earlier workers, especially near the eutectic composition, where differences in melting points as large as 35 K occur. Identification of the phases involved in the peritectic halt was not conclusive, but does support the proposal that the peritectic results from the formation of an Na2Cs intermetallic compound by a sluggish reaction.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"31-34"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716700031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57612841","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}
The pyrolysis of cyclopropane + argon mixtures has been studied in a single-pulse shock tube over the temperature range 1060–1870 K. At a total pressure of 500 mmHg and temperatures below 1300 K, an apparent first-order rate constant of 1011.9 exp (–230 kJ/RT) s–1 was obtained. This is in agreement with extrapolations from low temperature data provided allowance is made for the deviation from limiting first-order behaviour with increasing temperature. Above 1300 K, radical chain decomposition of the cyclopropane and/or the propylene product was observed but the overall loss of cyclopropane, which is best fitted by the expression 104.75 exp(–48.5 kJ/RT) s–1, was much lower than predicted by current unimolecular reaction rate theory. Various alternative mechanisms are examined but no acceptable explanation can yet be offered.
{"title":"Single-pulse shock tube studies of hydrocarbon pyrolysis. Part 1.—Pyrolysis of cyclopropane","authors":"J. N. Bradley, M. Frend","doi":"10.1039/TF9716700072","DOIUrl":"https://doi.org/10.1039/TF9716700072","url":null,"abstract":"The pyrolysis of cyclopropane + argon mixtures has been studied in a single-pulse shock tube over the temperature range 1060–1870 K. At a total pressure of 500 mmHg and temperatures below 1300 K, an apparent first-order rate constant of 1011.9 exp (–230 kJ/RT) s–1 was obtained. This is in agreement with extrapolations from low temperature data provided allowance is made for the deviation from limiting first-order behaviour with increasing temperature. Above 1300 K, radical chain decomposition of the cyclopropane and/or the propylene product was observed but the overall loss of cyclopropane, which is best fitted by the expression 104.75 exp(–48.5 kJ/RT) s–1, was much lower than predicted by current unimolecular reaction rate theory. Various alternative mechanisms are examined but no acceptable explanation can yet be offered.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"72-79"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716700072","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57612877","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}
A microwave-pulse temperature-jump technique has been used to study the proton-transfer reaction between 2,4-dinitrophenol and tri-n-butylamine in a number of solvents. The effect of solvent viscosity of the rate constant at room temperature indicates that diffusion processes influence the reaction. From a study of the reaction in chlorobenzene over the temperature range +38 to –14°, the apparent activation energy for the forward reaction is –3.5 kJ mol–1. Possible reasons for the inadequacy of the Stokes-Einstein equation in the present systems are discussed.
{"title":"Influence of temperature and solvent viscosity on the rate of the proton-transfer reaction between 2,4-dinitrophenol and tri-n-butylamine","authors":"K. J. Ivin, J. McGarvey, E. Simmons, R. Small","doi":"10.1039/TF9716700104","DOIUrl":"https://doi.org/10.1039/TF9716700104","url":null,"abstract":"A microwave-pulse temperature-jump technique has been used to study the proton-transfer reaction between 2,4-dinitrophenol and tri-n-butylamine in a number of solvents. The effect of solvent viscosity of the rate constant at room temperature indicates that diffusion processes influence the reaction. From a study of the reaction in chlorobenzene over the temperature range +38 to –14°, the apparent activation energy for the forward reaction is –3.5 kJ mol–1. Possible reasons for the inadequacy of the Stokes-Einstein equation in the present systems are discussed.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"864 1","pages":"104-109"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716700104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57612928","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}
The recombination coefficients for the recombination of nitrogen atoms on the surface of a number of metals and alloys have been measured using Smith's side-arm method. The constancy of activity for palladium, silver and a 50/50 alloys shows that d-band vacancies are unimportant. The results for Fe, Ni, Cu and Ni/Cu alloys suggest that with these materials a surface nitrate is formed and its properties are important in controlling the activity.
{"title":"Recombination of atoms at surfaces. Part 12.—Nitrogen atoms at some metal and alloy surfaces","authors":"M. L. Rahman, J. Linnett","doi":"10.1039/TF9716700183","DOIUrl":"https://doi.org/10.1039/TF9716700183","url":null,"abstract":"The recombination coefficients for the recombination of nitrogen atoms on the surface of a number of metals and alloys have been measured using Smith's side-arm method. The constancy of activity for palladium, silver and a 50/50 alloys shows that d-band vacancies are unimportant. The results for Fe, Ni, Cu and Ni/Cu alloys suggest that with these materials a surface nitrate is formed and its properties are important in controlling the activity.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"183-190"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716700183","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57613376","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}
P. Dickens, A. Halliwell, D. J. Murphy, M. Whittingham
The decomposition of ammonium paratungstate 5(NH4)2O.12WO3.5H2O in hydrogen has been studied thermogravimetrically and the formation of a hexagonal ammonium tungsten bronze phase, (NH4)xWO3(x∼0.25) established. Powder X-ray diffractometer studies, and measurements of electrical conductivity, magnetic susceptibility and reflectance spectra show that this phase is both iso-structural and iso-electronic with corresponding tungsten bronzes formed by potassium and rubidium.
{"title":"Preparation and characterization of a hexagonal ammonium tungsten bronze phase (NH4)xWO3","authors":"P. Dickens, A. Halliwell, D. J. Murphy, M. Whittingham","doi":"10.1039/TF9716700794","DOIUrl":"https://doi.org/10.1039/TF9716700794","url":null,"abstract":"The decomposition of ammonium paratungstate 5(NH4)2O.12WO3.5H2O in hydrogen has been studied thermogravimetrically and the formation of a hexagonal ammonium tungsten bronze phase, (NH4)xWO3(x∼0.25) established. Powder X-ray diffractometer studies, and measurements of electrical conductivity, magnetic susceptibility and reflectance spectra show that this phase is both iso-structural and iso-electronic with corresponding tungsten bronzes formed by potassium and rubidium.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"794-800"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716700794","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57615987","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}
A model of the radiation chemistry of liquids is derived from which the concentration of radicals as a function of time can be calculated. The model is based on the prescribed diffusion hypothesis of Jaffe-Lea-Samuel-Magee. It uses initial conditions similar to those of Mozumder and Magee. 25 It yields, inter alia, a simple one-parameter expression for molecular yields as a function of scavenger concentration. This is compared and gives good agreement with experimental results on molecular yields in aqueous solutions over a wide range of scavenger concentrations for a variety of scavengers.
{"title":"Expanding sphere model of the radiation chemistry of liquids","authors":"G. Stein, M. Tomkiewicz","doi":"10.1039/TF9716701016","DOIUrl":"https://doi.org/10.1039/TF9716701016","url":null,"abstract":"A model of the radiation chemistry of liquids is derived from which the concentration of radicals as a function of time can be calculated. The model is based on the prescribed diffusion hypothesis of Jaffe-Lea-Samuel-Magee. It uses initial conditions similar to those of Mozumder and Magee. 25 It yields, inter alia, a simple one-parameter expression for molecular yields as a function of scavenger concentration. This is compared and gives good agreement with experimental results on molecular yields in aqueous solutions over a wide range of scavenger concentrations for a variety of scavengers.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"1016-1028"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716701016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57616799","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}
The behaviour of 32P-recoils during thermal and photo-annealing has been compared in pure and oxygen-doped KCl single crystals using reactor irradiation and ion implantation techniques to generate the radiophosphorus. The existence of a new type of 32P(I)-precursor is shown to be responsible for thermal annealing below 140° in oxygen doped crystals. The new 32P(I)-precursor is also present in pure KCl after F-centre bleaching. The radiolysis products of the oxygen dopant and of the host lattice are observed to determine the variations in the valence distribution of 32P.
{"title":"Photo- and thermal-annealing reactions of 32P in pure and oxygen-doped KCl single crystals","authors":"T. Andersen, J. Baptista","doi":"10.1039/TF9716701213","DOIUrl":"https://doi.org/10.1039/TF9716701213","url":null,"abstract":"The behaviour of 32P-recoils during thermal and photo-annealing has been compared in pure and oxygen-doped KCl single crystals using reactor irradiation and ion implantation techniques to generate the radiophosphorus. The existence of a new type of 32P(I)-precursor is shown to be responsible for thermal annealing below 140° in oxygen doped crystals. The new 32P(I)-precursor is also present in pure KCl after F-centre bleaching. The radiolysis products of the oxygen dopant and of the host lattice are observed to determine the variations in the valence distribution of 32P.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"1213-1218"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716701213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57617872","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}
The mechanism of the decomposition of diethylsulphide on tungsten was studied by a dynamic treatment of adsorbed species during the reaction. When diethylsulphide was introduced to tungsten, the evolution of ethylene, ethane and hydrogen were observed in the initial stage of the reaction, and ethylmercaptan and hydrogen sulphide additionally in the later stage. In the initial stage, decomposed sulphur was consumed to form a surface sulphide layer, and after formation of the W8S and W4S layer, ethylmercaptan and hydrogen sulphide appeared in the gas phase. Further decomposition of diethylsulphide on the W4S layer produced no more layers of sulphide. The rate of decomposition of diethylsulphide in terms of ethylene and ethane formation was measured at the reaction temperature (250–300°C) as a function of the amount of adsorbed species. The rate of ethylene formation was first order with respect to the total amount of adsorbed C2 species, and that of ethane formation was first order with respect to the total amount of adsorbed C′2 species and the partial pressure of hydrogen respectively. It was therefore probable that the rate-determining step of the formation of ethylene was a surface reaction involving one molecule of the adsorbed diethylsulphide or corresponding species, and that of ethane formation was the hydrogenation of the intermediate of ethylene formation.
{"title":"Decomposition of diethylsulphide on tungsten. A dynamic treatment of surface catalysis","authors":"K. Fukuda","doi":"10.1039/TF9716701507","DOIUrl":"https://doi.org/10.1039/TF9716701507","url":null,"abstract":"The mechanism of the decomposition of diethylsulphide on tungsten was studied by a dynamic treatment of adsorbed species during the reaction. When diethylsulphide was introduced to tungsten, the evolution of ethylene, ethane and hydrogen were observed in the initial stage of the reaction, and ethylmercaptan and hydrogen sulphide additionally in the later stage. In the initial stage, decomposed sulphur was consumed to form a surface sulphide layer, and after formation of the W8S and W4S layer, ethylmercaptan and hydrogen sulphide appeared in the gas phase. Further decomposition of diethylsulphide on the W4S layer produced no more layers of sulphide. The rate of decomposition of diethylsulphide in terms of ethylene and ethane formation was measured at the reaction temperature (250–300°C) as a function of the amount of adsorbed species. The rate of ethylene formation was first order with respect to the total amount of adsorbed C2 species, and that of ethane formation was first order with respect to the total amount of adsorbed C′2 species and the partial pressure of hydrogen respectively. It was therefore probable that the rate-determining step of the formation of ethylene was a surface reaction involving one molecule of the adsorbed diethylsulphide or corresponding species, and that of ethane formation was the hydrogenation of the intermediate of ethylene formation.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"1507-1518"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716701507","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57620703","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}
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