IR spectra of 1,1,1-trifluoroethane (HFC-143a) have been recorded at medium and high resolution. Raman spectra in polarization controlled experiments have also been measured. Comparison between the spectra recorded with the two techniques has made possible a reassignment of the vibrational spectrum of CH3CF3 in the range 200–3100 cm-1. Room-temperature and low-temperature gas-phase spectra were compared in order to assign a large number of hot bands due to the low lying fundamentals ν6 (A2, ca. 220 cm-1) and ν12 (E, 366cm-1). An unambiguous assignment for ν8 has been obtained, together with a reliable frequency for ν6, which is forbidden in both the IR and Raman.
{"title":"Vibrational spectrum of 1,1,1-trifluoroethane","authors":"G. Nivellini, F. Tullini, A. Celli, M. Becucci","doi":"10.1039/A805068F","DOIUrl":"https://doi.org/10.1039/A805068F","url":null,"abstract":"IR spectra of 1,1,1-trifluoroethane (HFC-143a) have been recorded at medium and high resolution. Raman spectra in polarization controlled experiments have also been measured. Comparison between the spectra recorded with the two techniques has made possible a reassignment of the vibrational spectrum of CH3CF3 in the range 200–3100 cm-1. Room-temperature and low-temperature gas-phase spectra were compared in order to assign a large number of hot bands due to the low lying fundamentals ν6 (A2, ca. 220 cm-1) and ν12 (E, 366cm-1). An unambiguous assignment for ν8 has been obtained, together with a reliable frequency for ν6, which is forbidden in both the IR and Raman.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"49 1","pages":"2909-2912"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73864031","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}
M. Kohno, Takatoshi Kaneko, S. Ogura, Kazunori Sato, A. Y. Inoue
Ruthenium oxide supported on barium titanates (Ba6Ti17O40, Ba4Ti13O30, BaTi4O9 and Ba2Ti9O20) was employed as a photocatalyst for water decomposition. The RuCl3-impregnated titanates were subjected to either reduction or reduction–oxidation. High-resolution electron microscopic images demonstrated that ruthenium metal and ruthenium oxides were uniformly dispersed on BaTi4O9 with an average particle size of 2.6 nm. Similar uniform ruthenium oxide dispersions were observed for the other barium titanates; the average particle sizes were 4.7 nm for Ba6Ti17O40, 2.3 nm for Ba4Ti13O30, and 4.4 nm for Ba2Ti9O20. Particle size distributions were narrower for BaTi4O9 and Ba4Ti13O30, and slightly larger for Ba6Ti17O40 and Ba2Ti9O20. Stoichiometric production of oxygen and hydrogen occurred for a RuO2/BaTi4O9 photocatalyst. A small amount of hydrogen and no oxygen were produced from the other barium titanates (Ba6Ti17O40, Ba4Ti13O30 and Ba2Ti9O20) combined with ruthenium oxides. EPR spectra at 77 K in He or O2 with UV irradiation demonstrated that a strong signal, assigned to a surface O- radical, appeared for BaTi4O9 but not for the other barium titanates. These produced small complicated signals, indicating that only BaTi4O9 has a high efficiency for photoexcited charge formation. Raman spectra showed that a strong single peak at a high wavenumber of 860 cm-1, characteristic of BaTi4O9, was absent in the rest of the barium titanates. The different photocatalytic properties among these titanates are discussed on the basis of structure differences of the barium titanates, and the presence of internal fields; a long Ti–O bond in the distorted TiO6 octahedra is proposed to be important in photocatalysis.
{"title":"Dispersion of ruthenium oxide on barium titanates (Ba6Ti17O40,Ba4Ti13O30,BaTi4O9and Ba2Ti9O20)and photocatalytic activity for water decomposition","authors":"M. Kohno, Takatoshi Kaneko, S. Ogura, Kazunori Sato, A. Y. Inoue","doi":"10.1039/A704947A","DOIUrl":"https://doi.org/10.1039/A704947A","url":null,"abstract":"Ruthenium oxide supported on barium titanates (Ba6Ti17O40, Ba4Ti13O30, BaTi4O9 and Ba2Ti9O20) was employed as a photocatalyst for water decomposition. The RuCl3-impregnated titanates were subjected to either reduction or reduction–oxidation. High-resolution electron microscopic images demonstrated that ruthenium metal and ruthenium oxides were uniformly dispersed on BaTi4O9 with an average particle size of 2.6 nm. Similar uniform ruthenium oxide dispersions were observed for the other barium titanates; the average particle sizes were 4.7 nm for Ba6Ti17O40, 2.3 nm for Ba4Ti13O30, and 4.4 nm for Ba2Ti9O20. Particle size distributions were narrower for BaTi4O9 and Ba4Ti13O30, and slightly larger for Ba6Ti17O40 and Ba2Ti9O20. Stoichiometric production of oxygen and hydrogen occurred for a RuO2/BaTi4O9 photocatalyst. A small amount of hydrogen and no oxygen were produced from the other barium titanates (Ba6Ti17O40, Ba4Ti13O30 and Ba2Ti9O20) combined with ruthenium oxides. EPR spectra at 77 K in He or O2 with UV irradiation demonstrated that a strong signal, assigned to a surface O- radical, appeared for BaTi4O9 but not for the other barium titanates. These produced small complicated signals, indicating that only BaTi4O9 has a high efficiency for photoexcited charge formation. Raman spectra showed that a strong single peak at a high wavenumber of 860 cm-1, characteristic of BaTi4O9, was absent in the rest of the barium titanates. The different photocatalytic properties among these titanates are discussed on the basis of structure differences of the barium titanates, and the presence of internal fields; a long Ti–O bond in the distorted TiO6 octahedra is proposed to be important in photocatalysis.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"20 1","pages":"89-94"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74002218","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}
Molecular dynamics simulations of aqueous solutions containing methane and sodium chloride reveal the existence of a structured hydration shell around the non-polar solutes, although this hydration shell is less well defined than in the case where salt is absent. It was also observed that hydrogen bonds made from the hydration shell across to the bulk are weaker than those in the bulk, with or without salt. Although the geometry of the hydrogen bonds is preserved, there is a larger fraction of broken hydrogen bonds in the hydration shell of the non-polar solutes than in the bulk of the solution, the difference increasing with increasing temperature. The number of broken H bonds is significantly larger in the presence of salt, and should contribute to an increase in the free energy of dissolution and hence to a lowering of the solubility and an increase in the hydrophobic interaction.
{"title":"Computer simulation of the effect of salt on the hydrophobic effect","authors":"R. Mancera","doi":"10.1039/A806899B","DOIUrl":"https://doi.org/10.1039/A806899B","url":null,"abstract":"Molecular dynamics simulations of aqueous solutions containing methane and sodium chloride reveal the existence of a structured hydration shell around the non-polar solutes, although this hydration shell is less well defined than in the case where salt is absent. It was also observed that hydrogen bonds made from the hydration shell across to the bulk are weaker than those in the bulk, with or without salt. Although the geometry of the hydrogen bonds is preserved, there is a larger fraction of broken hydrogen bonds in the hydration shell of the non-polar solutes than in the bulk of the solution, the difference increasing with increasing temperature. The number of broken H bonds is significantly larger in the presence of salt, and should contribute to an increase in the free energy of dissolution and hence to a lowering of the solubility and an increase in the hydrophobic interaction.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"23 1","pages":"3549-3559"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74017257","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}
Raman spectra of the M2SO4–V2O5 (M=K or Cs) binary molten salt systems have been recorded at temperatures up to 570°C under an oxygen atmosphere and at different compositions in the range 0.25⩽X(V2O5)⩽0.50. 33 mol% V2O5 mixtures contain VV polymeric complexes consisted of VO3- and VO2(SO4)23- units participating in chain-like or network-like configurations, while VO2SO4- units were also detected in the K2SO4–V2O5 system. The spectral changes occurring upon addition of V2O5 up to X(V2O5)=0.50 are interpreted to indicate: (i) a gradual transformation of VO2(SO4)23- units, where vanadium is six-coordinated, to VO2SO4-, where vanadium is four-coordinated and (ii) extensive linking of polymeric chains giving rise to large and complex three-dimensional networks. The most characteristic bands observed for the various units comprising the polymeric complexes in the K2SO4–V2O5 system are assigned as follows: (i) for VO2(SO4)23- at 1042 (terminal VO stretches of six-coordinated vanadium), 940 (terminal S–O stretches of sulfate), 880 (bridging S–O), 668, 408 and 227 cm-1; (ii) for VO3- units at 950 (terminal VO stretches of four-coordinated vanadium), 486 and 365 cm-1 and (iii) for VO2SO4- units at 983 (terminal VO stretches of four-coordinated vanadium) and 862 cm-1 (bridging S–O). Similar values have been found for the band wavenumbers in the Cs2SO4–V2O5 system. The spectral data are discussed in terms of possible structural models. The spectral changes upon freezing the Cs2SO4–V2O5 molten mixtures with 0.33⩽X(V2O5)⩽0.50 indicate formation of the 1:1 V2O5·Cs2SO4 solid. This conclusion is confirmed also by powder XRD spectroscopy. For the first time, high-temperature vibrational spectroscopy has been used to establish the structural and vibrational properties of M2SO4–V2O5 (M=K or Cs) molten salt mixtures.
{"title":"Vibrational modes and structure of vanadium(V) complexes in M2SO4–V2O5 (M=K or Cs) molten salt mixtures","authors":"S. Boghosian","doi":"10.1039/A807047D","DOIUrl":"https://doi.org/10.1039/A807047D","url":null,"abstract":"Raman spectra of the M2SO4–V2O5 (M=K or Cs) binary molten salt systems have been recorded at temperatures up to 570°C under an oxygen atmosphere and at different compositions in the range 0.25⩽X(V2O5)⩽0.50. 33 mol% V2O5 mixtures contain VV polymeric complexes consisted of VO3- and VO2(SO4)23- units participating in chain-like or network-like configurations, while VO2SO4- units were also detected in the K2SO4–V2O5 system. The spectral changes occurring upon addition of V2O5 up to X(V2O5)=0.50 are interpreted to indicate: (i) a gradual transformation of VO2(SO4)23- units, where vanadium is six-coordinated, to VO2SO4-, where vanadium is four-coordinated and (ii) extensive linking of polymeric chains giving rise to large and complex three-dimensional networks. The most characteristic bands observed for the various units comprising the polymeric complexes in the K2SO4–V2O5 system are assigned as follows: (i) for VO2(SO4)23- at 1042 (terminal VO stretches of six-coordinated vanadium), 940 (terminal S–O stretches of sulfate), 880 (bridging S–O), 668, 408 and 227 cm-1; (ii) for VO3- units at 950 (terminal VO stretches of four-coordinated vanadium), 486 and 365 cm-1 and (iii) for VO2SO4- units at 983 (terminal VO stretches of four-coordinated vanadium) and 862 cm-1 (bridging S–O). Similar values have been found for the band wavenumbers in the Cs2SO4–V2O5 system. The spectral data are discussed in terms of possible structural models. The spectral changes upon freezing the Cs2SO4–V2O5 molten mixtures with 0.33⩽X(V2O5)⩽0.50 indicate formation of the 1:1 V2O5·Cs2SO4 solid. This conclusion is confirmed also by powder XRD spectroscopy. For the first time, high-temperature vibrational spectroscopy has been used to establish the structural and vibrational properties of M2SO4–V2O5 (M=K or Cs) molten salt mixtures.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"106 1","pages":"3463-3469"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79257101","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}
L. Stievano, S. Calogero, L. Storaro, M. Lenarda, F. Wagner
Intercalation of the gold thiourea (T) complex, AuT2+, into beidellite clay and aluminium pillared beidellite was studied by 197Au Mossbauer spectroscopy, X-ray diffraction and infrared spectroscopy. At a concentration close to the cation exchange capacity, the AuT2+ complexes are found to be oriented diagonal to the clay sheets, while at a much lower concentration and in the pillared beidellite they lie flat in the interlayer spacing. Thermal decomposition of the intercalated AuT2+ was studied at temperatures up to 400 °C.
{"title":"Metal complexes in a constrained environment","authors":"L. Stievano, S. Calogero, L. Storaro, M. Lenarda, F. Wagner","doi":"10.1039/A802967I","DOIUrl":"https://doi.org/10.1039/A802967I","url":null,"abstract":"Intercalation of the gold thiourea (T) complex, AuT2+, into beidellite clay and aluminium pillared beidellite was studied by 197Au Mossbauer spectroscopy, X-ray diffraction and infrared spectroscopy. At a concentration close to the cation exchange capacity, the AuT2+ complexes are found to be oriented diagonal to the clay sheets, while at a much lower concentration and in the pillared beidellite they lie flat in the interlayer spacing. Thermal decomposition of the intercalated AuT2+ was studied at temperatures up to 400 °C.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"60 1","pages":"2627-2632"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84787850","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. Givan, L. A. Larsen, A. Loewenschuss, C. Nielsen
Infrared spectra of H2SO4 vapors, which also include H2O and SO3, were trapped in argon matrices. Vibrational assignments for monomeric H2SO4 were established and additional bands were assigned to the (H2SO4)2, (H2O)·(H2SO4) and (H2O)2·(H2SO4) species. For the (H2O)·(H2SO4) complex, several isomers are shown to exist, the most stable being H2O·HOSO2OH. Temperature reversible changes in several bands of the latter complex are discussed in analogy to the trimeric (H2O)3 complex. The H2O and H2SO4 molecules dispersed in the argon solid do not affect the stabilization of a mixed (H2O)m·(SO3)n complex. No spectral evidence for ionized species due to proton transfer was found in the matrix samples investigated.
{"title":"Infrared matrix isolation study of H2SO4 and its complexes with H2O","authors":"A. Givan, L. A. Larsen, A. Loewenschuss, C. Nielsen","doi":"10.1039/A706675I","DOIUrl":"https://doi.org/10.1039/A706675I","url":null,"abstract":"Infrared spectra of H2SO4 vapors, which also include H2O and SO3, were trapped in argon matrices. Vibrational assignments for monomeric H2SO4 were established and additional bands were assigned to the (H2SO4)2, (H2O)·(H2SO4) and (H2O)2·(H2SO4) species. For the (H2O)·(H2SO4) complex, several isomers are shown to exist, the most stable being H2O·HOSO2OH. Temperature reversible changes in several bands of the latter complex are discussed in analogy to the trimeric (H2O)3 complex. The H2O and H2SO4 molecules dispersed in the argon solid do not affect the stabilization of a mixed (H2O)m·(SO3)n complex. No spectral evidence for ionized species due to proton transfer was found in the matrix samples investigated.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"194 1","pages":"827-835"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85007775","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}
Torbjörn Fängström, A. Kirrander, L. Eriksson, S. Lunell
Stationary points on the surface describing the reaction between aluminium and dimethyl ether (DME) have been located using density functional theory at the B3LYP level with a 6-31G(d,p) basis set. Hyperfine coupling constants (HFCC) of Al and the proton attached to it, as well as total energies, were computed at all stable structures using the B3LYP and BP86 functionals and the 6-311+G(2df,p) basis. Compared to earlier theoretical studies, additional stable conformers have been identified. An initial addition complex is formed between Al and CH3OCH3, located 4–9 kcal mol−1 below the free reactants in energy, depending on computational method. A first transition state connects the addition complex with a structure in which one hydrogen has migrated to the Al atom, whereafter a more stable C–H insertion structure is reached through a second transition state. A second reaction path leading to two C–O insertion products, starting from the addition complex, is also described. The most stable products are the cis and trans conformers of an open chain C–O insertion product which lie 58–65 kcal mol−1 below the reactants in energy. Among the C–H insertion products the most stable ones are cyclic cis and trans structures, which are found to lie 9–10 kcal mol−1 below the reactants.
{"title":"The reaction between aluminium and dimethyl ether Comparative study of density functional theory and EPR results","authors":"Torbjörn Fängström, A. Kirrander, L. Eriksson, S. Lunell","doi":"10.1039/A706667H","DOIUrl":"https://doi.org/10.1039/A706667H","url":null,"abstract":"Stationary points on the surface describing the reaction between aluminium and dimethyl ether (DME) have been located using density functional theory at the B3LYP level with a 6-31G(d,p) basis set. Hyperfine coupling constants (HFCC) of Al and the proton attached to it, as well as total energies, were computed at all stable structures using the B3LYP and BP86 functionals and the 6-311+G(2df,p) basis. Compared to earlier theoretical studies, additional stable conformers have been identified. An initial addition complex is formed between Al and CH3OCH3, located 4–9 kcal mol−1 below the free reactants in energy, depending on computational method. A first transition state connects the addition complex with a structure in which one hydrogen has migrated to the Al atom, whereafter a more stable C–H insertion structure is reached through a second transition state. A second reaction path leading to two C–O insertion products, starting from the addition complex, is also described. The most stable products are the cis and trans conformers of an open chain C–O insertion product which lie 58–65 kcal mol−1 below the reactants in energy. Among the C–H insertion products the most stable ones are cyclic cis and trans structures, which are found to lie 9–10 kcal mol−1 below the reactants.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"441 1","pages":"777-782"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85539682","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}
Precipitate systems display a variety of beautiful patterns. Of particular interest are those patterns formed by more than one insoluble salt. Guided by a prior theoretical model, we present here experiments on two precipitate patterning using PbI2 and PbF2 as the precipitating salts, in agar gel medium. Throughout the study, a solution of Pb2+ is allowed to diffuse into a homogeneous solution of the two halides and not the reverse. Two major categories of patterns are obtained: periodic, in which the band locations follow a rigorous spacing law, and aperiodic, where the bands occupy erratic spatial positions. The former patterns are obtained at large values of the mean concentration difference Δ [≡(ΔI + ΔF)/2, where ΔI = [Pb2+]0 − 1/2[I−]0 and similarly for ΔF], while the latter are formed at relatively low values of Δ. The periodic patterns show two different types of behaviour. When ΔI = ΔF, one type of bands containing the two precipitates is obtained, obeying the spacing law rigorously. When ΔI ≠ ΔF, two types of bands are observed with two distinct spacing laws. A chemical analysis of the bands shows that in both cases, the latter consist of a complete overlap of PbI2 and PbF— (i.e. no alternation) consistent with the initial ratio of concentrations (of I− to F−). Different observations favour the mechanism of post-nucleation patterning. Some special features indicate the role of the kinetics of particle growth in deciding whether we obtain one or two types of bands (and hence one or two spacing laws).
{"title":"Periodic and aperiodic patterns in non-equilibrium PbI2/PbF2 precipitate systems","authors":"M. Attieh, N. al-Kassem, R. Sultan","doi":"10.1039/A801391H","DOIUrl":"https://doi.org/10.1039/A801391H","url":null,"abstract":"Precipitate systems display a variety of beautiful patterns. Of particular interest are those patterns formed by more than one insoluble salt. Guided by a prior theoretical model, we present here experiments on two precipitate patterning using PbI2 and PbF2 as the precipitating salts, in agar gel medium. Throughout the study, a solution of Pb2+ is allowed to diffuse into a homogeneous solution of the two halides and not the reverse. Two major categories of patterns are obtained: periodic, in which the band locations follow a rigorous spacing law, and aperiodic, where the bands occupy erratic spatial positions. The former patterns are obtained at large values of the mean concentration difference Δ [≡(ΔI + ΔF)/2, where ΔI = [Pb2+]0 − 1/2[I−]0 and similarly for ΔF], while the latter are formed at relatively low values of Δ. The periodic patterns show two different types of behaviour. When ΔI = ΔF, one type of bands containing the two precipitates is obtained, obeying the spacing law rigorously. When ΔI ≠ ΔF, two types of bands are observed with two distinct spacing laws. A chemical analysis of the bands shows that in both cases, the latter consist of a complete overlap of PbI2 and PbF— (i.e. no alternation) consistent with the initial ratio of concentrations (of I− to F−). Different observations favour the mechanism of post-nucleation patterning. Some special features indicate the role of the kinetics of particle growth in deciding whether we obtain one or two types of bands (and hence one or two spacing laws).","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"19 1","pages":"2187-2194"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82150381","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. Wakisaka, H. Abdoul-Carime, Y. Yamamoto, Y. Kiyozumi
Water–methanol and water–acetonitrile, which show exothermic and endothermic mixing, respectively, represent good contrast in non-ideality of a binary mixture. The microscopic structure observed through the mass-spectrometric analysis of clusters isolated from solution also shows good contrast between these binary mixtures as follows: (1) methanol molecules have substitutional interaction with water clusters, while acetonitrile molecules have additional interaction with water clusters; (2) the clustering of methanol molecules are promoted in the presence of water; on the contrary, the acetonitrile clusters are disintegrated in the presence of water. Such findings could partially explain the non-ideality of these binary mixtures on the basis of the cluster structures.
{"title":"Non-ideality of binary mixtures Water[ndash ]methanol and water[ndash ]acetonitrile from the viewpoint of clustering structure","authors":"A. Wakisaka, H. Abdoul-Carime, Y. Yamamoto, Y. Kiyozumi","doi":"10.1039/A705777F","DOIUrl":"https://doi.org/10.1039/A705777F","url":null,"abstract":"Water–methanol and water–acetonitrile, which show exothermic and endothermic mixing, respectively, represent good contrast in non-ideality of a binary mixture. The microscopic structure observed through the mass-spectrometric analysis of clusters isolated from solution also shows good contrast between these binary mixtures as follows: (1) methanol molecules have substitutional interaction with water clusters, while acetonitrile molecules have additional interaction with water clusters; (2) the clustering of methanol molecules are promoted in the presence of water; on the contrary, the acetonitrile clusters are disintegrated in the presence of water. Such findings could partially explain the non-ideality of these binary mixtures on the basis of the cluster structures.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"13 1","pages":"369-374"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79658239","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}
J. García, L. Lugo, M. Comuñas, E. R. López, Josefa Fernández
Excess volumes at 298.15 K and atmospheric pressure of some organic carbonate+alkane binary systems have been measured using an Anton Paar 602 HP densimeter. For the first time, published data on excess enthalpies, excess volumes, excess Gibbs energies of the above-mentioned binary systems together with the vaporisation enthalpies and the molar volumes of the pure organic carbonates, were used to estimate the interaction parameters between the carbonate group O–CO–O and the methyl and methylene groups, CH3, CH2, respectively. The mean deviations between experimental and theoretical values were smaller than 6% for all the properties. We have also compared our results with those obtained by Garcia etal. with the Original, Tassios etal., Larsen etal. and Gmehling etal. versions of the UNIFAC model and with those obtained by Kehiaian etal. using the DISQUAC model.
{"title":"Experimental excess volumes of organic carbonate+alkane systems. Estimation of the parameters of the Nitta–Chao model for this kind of binary mixture","authors":"J. García, L. Lugo, M. Comuñas, E. R. López, Josefa Fernández","doi":"10.1039/A800934A","DOIUrl":"https://doi.org/10.1039/A800934A","url":null,"abstract":"Excess volumes at 298.15 K and atmospheric pressure of some organic carbonate+alkane binary systems have been measured using an Anton Paar 602 HP densimeter. For the first time, published data on excess enthalpies, excess volumes, excess Gibbs energies of the above-mentioned binary systems together with the vaporisation enthalpies and the molar volumes of the pure organic carbonates, were used to estimate the interaction parameters between the carbonate group O–CO–O and the methyl and methylene groups, CH3, CH2, respectively. The mean deviations between experimental and theoretical values were smaller than 6% for all the properties. We have also compared our results with those obtained by Garcia etal. with the Original, Tassios etal., Larsen etal. and Gmehling etal. versions of the UNIFAC model and with those obtained by Kehiaian etal. using the DISQUAC model.","PeriodicalId":17286,"journal":{"name":"Journal of the Chemical Society, Faraday Transactions","volume":"55 1","pages":"1707-1712"},"PeriodicalIF":0.0,"publicationDate":"1998-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84713651","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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