摘要:

The equilibrium between thecisand thetransisomers of the biacetyl radical anion has been studied by esr spectroscopy. The dependence of this equilibrium on the solvent composition and temperature was followed.

ISSN:0008-4042    

DOI:10.1139/v76-522

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Anionic complexes of cadmium, of the type [CdX2Y]−, where X and Y are chlorine, bromine or iodine, have been prepared as the tetra-n-propylammonium salts. Raman spectra have been recorded, and serve to establish that these anions haveC2vsymmetry in the solid state. Force constants calculated on the Urey–Bradley approximation are correlated with previously reported results for CdX3−species.

ISSN:0008-4042    

DOI:10.1139/v76-523

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The initial stage of reduction of anhydrous sulfates by H2may lead to the formation of any of the following: (1) sulfates at lower valency,e.g., reduction of CuSO4, HgSO4, Fe2(SO4)3; (2) metals,e.g., Cu2SO4, Ag2SO4; (3) sulfides,e.g., NiSO4, CoSO4, CdSO4, CaSO4, SrSO4, BaSO4, and alkaline metal sulfates; (4) oxides,e.g., Al2(SO4)3, MgSO4, BeSO4; (5) a mixture of oxide and sulfide,e.g., FeSO4, MnSO4, ZnSO4, PbSO4. While CuSO4, Ag2SO4, and PbSO4are the only sulfates that yield metals on reduction, CuSO4is the most interesting because it yields the metal at 350 °C. PbSO4is reduced to metal at about 800 °C, and Ag2SO4already yields the metal by thermal decomposition above 800 °C.

ISSN:0008-4042    

DOI:10.1139/v76-524

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The reduction of a binary sulfate mixture cannot be predicted from the behavior of the individual components. Thus, while CuSO4is reduced to Cu at 400 °C and NiSO4is reduced to Ni3S2, the sulfate mixture yields Cu, Ni3S2, and Cu2S. Also while FeSO4is completely stable in H2at 400 °C, (Cu,Fe) SO4yields Cu and Cu5FeS4. The formation of Cu2S in the first case and Cu5FeS4in the second was unexpected. On the other hand, (Cu,Mn)SO4is stable in H2up to 550 °C although pure CuSO4is completely reduced at 400 °C. CoSO4also interferes when reduced in presence of CuSO4, while Na2SO4, MgSO4, Al2(SO4)3, ZnSO4, CdSO4do not interfere within limited temperature range. Of these only Na2SO4forms a complex sulfate with CuSO4. No Cu2SO4was identified when CuSO4was reduced in presence of other sulfates although it is an intermediate product during the reduction of pure CuSO4.

ISSN:0008-4042    

DOI:10.1139/v76-525

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A reaction has been studied between two reactants where one, ionic, is dissolved in the aqueous phase and the other, nonionic, is distributed between the aqueous phase and a micellar phase. The kinetic study of this reaction has helped to elucidate the mechanism of the reaction.Depending on the experimental conditions, it is possible to have either an equilibrium of the nonionic solute between the aqueous and micellar phases, or a reaction rate limited by the rate of diffusion of this reactant from the micellar phase to the aqueous phase. It will be shown that such kinetic studies can be used to determine quantitatively the distribution of the solute between the various phases and even inside the micelles. [Journal translation]

ISSN:0008-4042    

DOI:10.1139/v76-526

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The proton magnetic resonance spectra in the absence of intermolecular proton exchange for 0.27, 0.59, and 0.79 Msolutions of phenol in CCl4are analyzed. The long-range coupling over five bonds between the hydroxyl and ring protons is estimated as 0.33 Hz in the monomer and as 0.20 Hz in the trimer of a monomer–trimer model. Support for the decrease in the coupling on trimerization is found in CNDO/2 and INDO MO FPT calculations. The long-range coupling over six bonds is unobservable, consistent with conformations of the trimer in which the phenol molecules remain planar. Water catalyzes the intermolecular proton exchange and, in its absence, the transfer of hydroxyl protons from molecule to molecule within the associated species is inefficient.

ISSN:0008-4042    

DOI:10.1139/v76-527

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The formation of Na−from K, Rb, Cs, or Li ethylamide solutions containing small amounts of Na+has been observed by pulse radiolysis. In K, Rb, or Cs solutions evidence is presented which shows that the production of Na−occurs via the corresponding alkali anions K−, Rb−, or Cs−. However solutions containing Li behave much differently and indicate that Na+is 'complexed' or associated with Li+ions. Probable reaction mechanisms are discussed.

ISSN:0008-4042    

DOI:10.1139/v76-528

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The motions of water molecules in ethylene oxide-d4clathrate hydrate have been studied between 200 and 280 K using continuous wave and pulsed1H nmr methods. The1H second moment and rotating frame relaxation time variation with temperature show that reorientation and diffusion of water molecules occur as two distinct processes. From the relaxation time data, activation energies of 8.15 and 12.0 kcal/mol are found for reorientation and diffusion, respectively.From the non-zero guest molecule D quadrupole coupling constant observed between ∼100 and 280 K, it is evident that there is some net orientation of the guest molecules in the hydrate cages at all temperatures. Also, there is a slow motional averaging superimposed on the rapid guest molecule reorientation which can be described approximately by the same parameters as the water molecule reorientation.

ISSN:0008-4042    

DOI:10.1139/v76-529

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Simple anation and solvent exchange reactions of Co(NH3)5DMSO3+in DMSO are accompanied by reactions in which the conjugate base of this complex undergoes either internal redox to cobalt(II) or relatively rapid substitution. These conjugate base reactions are eliminated by addition of H+, although a minor redox pathway persists within ion pairs of Co(NH3)5DMSO3+with chloride or bromide. The latter pathway is evidently not mechanistically related to the solvent exchange or anation reactions, which proceed by dissociative interchange (Id) according to the activation parameters (volume of activation = +10 cm3mol−1for DMSO exchange; enthalpy of activation = 123, 121, and ∼126 kJ mol−1for DMSO exchange and bromide and chloride anation respectively). Enthalpies of activation for solvent exchange and for the limiting anation rate are shown to be better criteria of mechanism than the corresponding rate coefficients.

ISSN:0008-4042    

DOI:10.1139/v76-530

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The optical absorption band of electrons solvated in ethers has an approximately Gaussian shape on the low energy side of the absorption maximum. The high energy side is wider and has an approximately Lorentzian shape down toA/Amax ≈ 0.3, then extends into a long tail to high energies. The energy at the absorption maximum EAmaxand the Gaussian and Lorentzian dispersion parametersgandlare reported as functions of temperature for electrons in diethyl ether (DEE), di-n-propyl ether (DPE), di-n-butyl ether (DBE), and tetrahydrofuran (THF). The values in eV of the parameters at 180 K are:EAmax = 0.76 in THF, 0.67 in DEE, 0.65 in DPE and DBE;l = 0.32 in THF, DEE, and DPE, 0.39 in DBE;g = 0.19 in all the ethers. The temperature coefficients ofEAmaxare ∼ −2 × 10−3 eV/K, those oflare −(1 ± 1)10−4 eV/K, and those ofgare +4 × 10−4 eV/K. The band becomes less asymmetrical as the temperature increases. To make progress in the theoretical treatment of solvated electron spectra attention should be focussed on the separate values ofgandland their temperature dependences; the width at half heightW1/2thereby loses theoretical significance. The decadic molar absorbancy ϵmax(M−1cm−1) is 2.9 × 104in DEE and DPE, 2.6 × 104in DBE, and 2.1 × 104in THF. The oscillator strengthsfare 0.7 in then-alkyl ethers and 0.6 in THF. The value ofEAmaxinp-dioxane is 0.1 eV greater than that in THF and about 0.2 eV greater than those in the open chain ethers. This agrees with a prediction based upon the relative mobilities of electrons in the ether

ISSN:0008-4042    

DOI:10.1139/v76-531

出版商:NRC Research Press    

年代:1976

数据来源: NRC