The 35Cl n.q.r. frequencies of seven N-chloro molecules are reported and with those of five additional molecules in the literature, interpreted using BEEM and BEEM-π. The frequency is dependent on the hybridization of the N atom: with tr1tr1tr1π2 hybridized N the 35Cl frequency is around 55 MHz, with tr1tr1tr2π1hybridized N around 46 MHz and with te1te1te1te2 hybridized N at 44 MHz.
{"title":"35Cl nuclear quadrupole resonance of the N—Cl bond","authors":"R. Hart, M. Whitehead","doi":"10.1039/TF9716701569","DOIUrl":"https://doi.org/10.1039/TF9716701569","url":null,"abstract":"The 35Cl n.q.r. frequencies of seven N-chloro molecules are reported and with those of five additional molecules in the literature, interpreted using BEEM and BEEM-π. The frequency is dependent on the hybridization of the N atom: with tr1tr1tr1π2 hybridized N the 35Cl frequency is around 55 MHz, with tr1tr1tr2π1hybridized N around 46 MHz and with te1te1te1te2 hybridized N at 44 MHz.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"727 1","pages":"1569-1575"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716701569","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57620661","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 absorption spectrum of SiBr, observed in the flash photolysis of SiBr4, consists of the B2Σ—X2Π system and a number of new band systems at shorter wavelengths. One of these is shown to be analogous to the C2Π—X2Π systems of SiF and SiCl, and state C has the following parameters : Te= 41 051 cm–1, A= 12 cm–1, ωe= 531 cm–1, ωexe= 2 cm–1. Analyses of the remaining band systems are also discussed.
{"title":"Ultra-violet spectrum of SiBr","authors":"G. Oldershaw, K. Robinson","doi":"10.1039/TF9716701870","DOIUrl":"https://doi.org/10.1039/TF9716701870","url":null,"abstract":"The absorption spectrum of SiBr, observed in the flash photolysis of SiBr4, consists of the B2Σ—X2Π system and a number of new band systems at shorter wavelengths. One of these is shown to be analogous to the C2Π—X2Π systems of SiF and SiCl, and state C has the following parameters : Te= 41 051 cm–1, A= 12 cm–1, ωe= 531 cm–1, ωexe= 2 cm–1. Analyses of the remaining band systems are also discussed.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"1870-1874"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716701870","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57623826","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 absolute intensity of dimole emission at 6340 A by two O21Δg is found to be 16±4 [O21Δg]2 in cm3 mol–1 s–1 units. The rate constants for their energy pooling to yield O21Σ+g, ν= 0 and 1 are (1.2±0.3)× 107 and 6 × 105 cm3 mol–1 s–1 respectively. The removal of O21Σ+g at the walls is partly diffusion controlled, rate constants for its deactivation by H2O and H2 are reported.
{"title":"Measurements on O21Δg and O21Σ+g in discharge flow systems","authors":"R. Derwent, B. Thrush","doi":"10.1039/TF9716702036","DOIUrl":"https://doi.org/10.1039/TF9716702036","url":null,"abstract":"The absolute intensity of dimole emission at 6340 A by two O21Δg is found to be 16±4 [O21Δg]2 in cm3 mol–1 s–1 units. The rate constants for their energy pooling to yield O21Σ+g, ν= 0 and 1 are (1.2±0.3)× 107 and 6 × 105 cm3 mol–1 s–1 respectively. The removal of O21Σ+g at the walls is partly diffusion controlled, rate constants for its deactivation by H2O and H2 are reported.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"49 1","pages":"2036-2043"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57625482","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 radiolysis of Tl2SO4 in neutral and in 0.8 N H2SO4 aqueous solutions in the presence and absence of air was investigated. In the absence of air and with low doses of radiation, a steady-state concentration of H2O2 is observed. In air-saturated solution G(H2O2) decreases with Tl+ concentration. The effect of Tl+ on GH2O2 was measured by two independent methods, following G(H2O2) in aerated solutions and by measuring G(H2O218, 18) formed in H2O18 in the presence of H2O216, 16 as protective additive. In neutral and acid solutions, G(H2)=GH2= 0.42±0.02, which was independent of Tl+ concentration. The relatively high efficiency of Tl+ for scavenging the precursor of H2O2 is discussed and compared with that of other reactants known to diminish GH2O2. The mode of formation of the “molecular” products in the radiolysis of water is discussed in the light of the findings.
研究了Tl2SO4在中性和0.8 N H2SO4水溶液中在有空气和无空气条件下的放射性溶解。在没有空气和低剂量辐射的情况下，可以观察到稳定的H2O2浓度。在空气饱和溶液中，G(H2O2)随Tl+浓度的增加而降低。采用两种独立的方法测定Tl+对GH2O2的影响，一种是在充气溶液中测定G(H2O2)，另一种是在H2O216, 16作为保护添加剂存在时测定H2O18中形成的G(H2O218, 18)。在中性和酸性溶液中，G(H2)=GH2= 0.42±0.02，与Tl+浓度无关。讨论了Tl+清除H2O2前体的相对高效率，并与其他已知的减少GH2O2的反应物进行了比较。根据这些发现，讨论了水的辐射分解过程中“分子”产物的形成方式。
{"title":"Effect of thallous ions on the yields of hydrogen and hydrogen peroxide in radiolyzed aqueous solutions","authors":"M. Faraggi, D. Zehavi, M. Anbar","doi":"10.1039/TF9716702057","DOIUrl":"https://doi.org/10.1039/TF9716702057","url":null,"abstract":"The radiolysis of Tl2SO4 in neutral and in 0.8 N H2SO4 aqueous solutions in the presence and absence of air was investigated. In the absence of air and with low doses of radiation, a steady-state concentration of H2O2 is observed. In air-saturated solution G(H2O2) decreases with Tl+ concentration. The effect of Tl+ on GH2O2 was measured by two independent methods, following G(H2O2) in aerated solutions and by measuring G(H2O218, 18) formed in H2O18 in the presence of H2O216, 16 as protective additive. In neutral and acid solutions, G(H2)=GH2= 0.42±0.02, which was independent of Tl+ concentration. The relatively high efficiency of Tl+ for scavenging the precursor of H2O2 is discussed and compared with that of other reactants known to diminish GH2O2. The mode of formation of the “molecular” products in the radiolysis of water is discussed in the light of the findings.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2057-2067"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57625610","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 volume change on mixing polystyrene with ethylbenzene has been determined directly at 25°C. It is negative and amounts to ca. 0.30 % of the total volume at ϕ2= 0.5. Osmotic pressures have been measured at 10°, 35°, and 60°C in the concentration range ϕ2= 0.09 to 0.27. The temperature coefficient of the reduced residual chemical potential χ is close to zero; hence the heat of dilution is very small. The entropy of dilution is positive but small. The statistical thermodynamic theory employed in the preceding paper accounts for the sign and magnitude of the excess volume. The experimental partial molar entropies are much smaller than the combinatory contribution alone would allow. This finding and the small negative enthalpy of dilution indicated by recent work of Palmen are shown to arise mainly from equation-of-state terms of the newer theory. The parameter X12 representing the exchange enthalpy is positive and small, as should be expected for this system. The observed increase in χ with concentration is well reproduced by the theory. Thermal expansivities and thermal pressure coefficients of ethylbenzene have been determined at atmospheric pressure from 10° to 90°C.
{"title":"Thermodynamics of polystyrene solutions. Part 2.—Polystyrene and ethylbenzene","authors":"H. Höcker, P. Flory","doi":"10.1039/TF9716702270","DOIUrl":"https://doi.org/10.1039/TF9716702270","url":null,"abstract":"The volume change on mixing polystyrene with ethylbenzene has been determined directly at 25°C. It is negative and amounts to ca. 0.30 % of the total volume at ϕ2= 0.5. Osmotic pressures have been measured at 10°, 35°, and 60°C in the concentration range ϕ2= 0.09 to 0.27. The temperature coefficient of the reduced residual chemical potential χ is close to zero; hence the heat of dilution is very small. The entropy of dilution is positive but small. The statistical thermodynamic theory employed in the preceding paper accounts for the sign and magnitude of the excess volume. The experimental partial molar entropies are much smaller than the combinatory contribution alone would allow. This finding and the small negative enthalpy of dilution indicated by recent work of Palmen are shown to arise mainly from equation-of-state terms of the newer theory. The parameter X12 representing the exchange enthalpy is positive and small, as should be expected for this system. The observed increase in χ with concentration is well reproduced by the theory. Thermal expansivities and thermal pressure coefficients of ethylbenzene have been determined at atmospheric pressure from 10° to 90°C.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"95 1","pages":"2270-2274"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702270","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57627076","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}
Viscosity and density measurements at 25°C on solutions of small straight-chain and cyclic quaternary ammonium iodides, and on methyl and ethyl pyridinium iodide are reported. The derived apparent molal volumes ϕ°ν and viscosity B-coefficients Bη change by constant amounts (0.015 dm3 mol–1 and 0.067 dm3 mol–1 respectively) per CH2 group for all except the pyridinium salts, and are related by the equation Bη= 4.6 ϕ°ν–0.54.
{"title":"Dilute aqueous solutions of unsymmetrical quaternary ammonium iodides. Part 1.—Viscosity and density measurements","authors":"B. M. Lowe, H. M. Rendall","doi":"10.1039/TF9716702318","DOIUrl":"https://doi.org/10.1039/TF9716702318","url":null,"abstract":"Viscosity and density measurements at 25°C on solutions of small straight-chain and cyclic quaternary ammonium iodides, and on methyl and ethyl pyridinium iodide are reported. The derived apparent molal volumes ϕ°ν and viscosity B-coefficients Bη change by constant amounts (0.015 dm3 mol–1 and 0.067 dm3 mol–1 respectively) per CH2 group for all except the pyridinium salts, and are related by the equation Bη= 4.6 ϕ°ν–0.54.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2318-2327"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702318","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57627526","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 point-source technique for measuring gas-phase diffusion coefficients has been tested using trace quantities of nitric oxide diffusing in the burnt gases of atmospheric pressure flames of H2+ O2+ N2. The air afterglow emission was used to monitor concentrations of nitric oxide. The results validate quantitatively the technique, and diffusion coefficients for nitric oxide have been measured over the temperature range 1920–2520 K. These data can be accounted for with either a Lennard-Jones (12: 6) potential or a purely repulsive inverse power potential function to describe interactions of a nitric oxide molecule with those of the principal flame species. A slight preference for the second potential function is indicated. With the Lennard-Jones function it is not possible to arrive at one unique pair of force constants for NO. However, either σ= 3.60 × 10–10 m and (Iµ/k)= 85 K or σ= 3.58 × 10–10 m and (Iµ/k)= 91 K can be used to calculate diffusion coefficients with reasonable accuracy. For the other potential function, repulsive forces varying inversely with separation to the 12th power fit the measured diffusion coefficients best. Values of the corresponding force constants are given.
{"title":"Flame photometric determinations of diffusion coefficients. Part 3.—Results for nitric oxide","authors":"A. Ashton, A. Hayhurst","doi":"10.1039/TF9716702348","DOIUrl":"https://doi.org/10.1039/TF9716702348","url":null,"abstract":"The point-source technique for measuring gas-phase diffusion coefficients has been tested using trace quantities of nitric oxide diffusing in the burnt gases of atmospheric pressure flames of H2+ O2+ N2. The air afterglow emission was used to monitor concentrations of nitric oxide. The results validate quantitatively the technique, and diffusion coefficients for nitric oxide have been measured over the temperature range 1920–2520 K. These data can be accounted for with either a Lennard-Jones (12: 6) potential or a purely repulsive inverse power potential function to describe interactions of a nitric oxide molecule with those of the principal flame species. A slight preference for the second potential function is indicated. With the Lennard-Jones function it is not possible to arrive at one unique pair of force constants for NO. However, either σ= 3.60 × 10–10 m and (Iµ/k)= 85 K or σ= 3.58 × 10–10 m and (Iµ/k)= 91 K can be used to calculate diffusion coefficients with reasonable accuracy. For the other potential function, repulsive forces varying inversely with separation to the 12th power fit the measured diffusion coefficients best. Values of the corresponding force constants are given.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2348-2353"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702348","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57627829","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 kinetics of the photochemically-induced depolymerization of poly(methyl methacrylate) are investigated. Monochromatic ultra-violet radiation, wave-length 253.7 nm, was used on samples heated in vacuum to temperatures from 433 to 473 K. It is concluded that the mechanism is one of random scission of the polymer main-chain bonds followed by complete unzipping of the molecules.
{"title":"Photolytic decomposition of polymethacrylates. Part. 1.—Poly(methyl methacrylate); kinetics of decomposition","authors":"J. R. Maccallum, C. Schoff","doi":"10.1039/TF9716702372","DOIUrl":"https://doi.org/10.1039/TF9716702372","url":null,"abstract":"The kinetics of the photochemically-induced depolymerization of poly(methyl methacrylate) are investigated. Monochromatic ultra-violet radiation, wave-length 253.7 nm, was used on samples heated in vacuum to temperatures from 433 to 473 K. It is concluded that the mechanism is one of random scission of the polymer main-chain bonds followed by complete unzipping of the molecules.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2372-2382"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702372","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57627851","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 main products of the photolysis of aromatic azides in matrices of polystyrene, paraffin wax, polyisoprene and some other polymers are primary and secondary amines. The yield of secondary amine in the matrix depends strongly on the rigidity of the polymeric system. Matrix rigidity affects also the reaction kinetics of the nitrene intermediate, lifetimes of photogenerated triplet nitrenes being up to three orders of magnitude longer in rigid matrices than in plasticized materials. From the results of flash photolysis experiments, it is concluded that in the rigid matrix the rate of interaction between a reactive species and the polymer is not controlled by the chemical reactivities of reactant and substrate, but by a steric rearrangement of the polymer chain in the vicinity of the reactive site.
{"title":"Effect of matrix rigidity on the reactions of aromatic nitrenes in polymers","authors":"A. Reiser, L. Leyshon, L. Johnston","doi":"10.1039/TF9716702389","DOIUrl":"https://doi.org/10.1039/TF9716702389","url":null,"abstract":"The main products of the photolysis of aromatic azides in matrices of polystyrene, paraffin wax, polyisoprene and some other polymers are primary and secondary amines. The yield of secondary amine in the matrix depends strongly on the rigidity of the polymeric system. Matrix rigidity affects also the reaction kinetics of the nitrene intermediate, lifetimes of photogenerated triplet nitrenes being up to three orders of magnitude longer in rigid matrices than in plasticized materials. From the results of flash photolysis experiments, it is concluded that in the rigid matrix the rate of interaction between a reactive species and the polymer is not controlled by the chemical reactivities of reactant and substrate, but by a steric rearrangement of the polymer chain in the vicinity of the reactive site.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2389-2396"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702389","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57627862","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}
N. T. Watkins, D. Jeter, W. Hatfield, S. M. Horner
The magnetic susceptibility of bis(dimethylsulphoxide)copper(II) chloride has been measured in the temperature range 4.2–298 K. Antiferromagnetic interactions were observed at very low temperatures. The data are interpreted in terms of electron spin interactions along an infinite chain of copper(II) atoms.
{"title":"Antiferromagnetic interactions in bis(dimethylsulphoxide)copper(II) chloride","authors":"N. T. Watkins, D. Jeter, W. Hatfield, S. M. Horner","doi":"10.1039/TF9716702431","DOIUrl":"https://doi.org/10.1039/TF9716702431","url":null,"abstract":"The magnetic susceptibility of bis(dimethylsulphoxide)copper(II) chloride has been measured in the temperature range 4.2–298 K. Antiferromagnetic interactions were observed at very low temperatures. The data are interpreted in terms of electron spin interactions along an infinite chain of copper(II) atoms.","PeriodicalId":23290,"journal":{"name":"Transactions of The Faraday Society","volume":"67 1","pages":"2431-2435"},"PeriodicalIF":0.0,"publicationDate":"1971-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1039/TF9716702431","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"57628019","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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