摘要:

The partial molal volumes of four tetraalkylammonium chlorides, Me4NCl, Et4NCl, Pr4NCl, and Bu4NCl, in a series of ethanol–water mixtures have been determined. The experimental results are discussed in terms of the varying size and surface charge of the ions and the structure of the binary solvent mixtures. The results indicate that at 0.1 mole fraction ethanol the maximum structuredness of water causes a minimum in the partial molal volumes, while at 0.3 mole fraction the solvent structure is such that the free volume is a minimum but the effect of surface charge on the salts is a maximum.

ISSN:0008-4042    

DOI:10.1139/v68-383

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Sulfane crude oils obtained by acidification of aqueous sodium polysulfide solutions vary little in composition with varying sulfur content of the solution. Evidence presented suggests that the distribution of the sulfanes in such crude oils reflects the equilibrated distribution of the various polysulfide anions in the aqueous solution before acidification. The sulfane distribution in mixtures obtained by reaction of liquid H2S with Br2, SCl2, and S2Cl2respectively varies over a wide range, depending on the molar ratio of the reactants. Liquid H2S reacts with Br2or SCl2to yield essentially the same products. These reactions, however, differ in the nature of their intermediates. By using a large excess of liquid H2S, H2S3was directly synthesized in over 90% purity. Liquid H2S reacts with S2Cl2to yield H2S4in over 90% purity. Gaseous HCl catalyzes the reaction of H2S with the chlorosulfanes and a mechanism is suggested involving HCl as a proton transfer agent in the formation of the reactive intermediates.

ISSN:0008-4042    

DOI:10.1139/v68-384

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A careful examination of the Raman and infrared spectra of the crystalline planar complexescis-andtrans-MX2•2RCN, where M = Pd or Pt, X = Cl or Br, and R = Me or Ph, reveals intense absorption bands in the 125–80 cm−1region which can be assigned to modes involving stretching of the metal–nitrogen bonds. Alternative assignments for v(M—N) are also discussed. These results are compared with those for other metal halide – RCN systems. The complexestrans-PtBr2•2RCN are described for the first time.

ISSN:0008-4042    

DOI:10.1139/v68-385

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Ketene has been photolyzed at 3660 and 3130 Å both alone and in the presence of the inert gases C4F8and SF6. The quantum yield of carbon monoxide has been determined at both wavelengths as a function of pressure and temperature. At 3660 Å the quantum yield decreases with increasing pressure but increases with increasing temperature. At 3130 Å the quantum yield with ketene alone remains 2.0 at both 37 and 100 °C at pressures up to 250 mm. At higher pressures of ketene or with added inert gas the quantum yield decreases with increasing pressure. The results are interpreted in terms of a mechanism in which intersystem crossing from the excited singlet state to the triplet state occurs at both wavelengths, and collisional deactivation of the excited singlet state by ketene is single stage at 3660 Å but multistage at 3130 Å.

ISSN:0008-4042    

DOI:10.1139/v68-386

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Cobalt(II) halide complexes [CoX2•2L] (X = Cl, Br, I and L = 2-thiazolidinethione) and [CoL4] (ClO4)2have been prepared. The infrared spectral study suggests that the probable site of bonding in the ligand is nitrogen. The results of electronic spectral study and magnetic susceptibility measurements indicate that the complexes are tetrahedral in structure. The various ligand field parametersDq,B′, and β show about 80% covalency in the complexes and suggest a weak ligand field.

ISSN:0008-4042    

DOI:10.1139/v68-387

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Dielectric constant and loss data have been obtained at microwave frequencies for acridine, 4-methyl-pyridine, phthalazine, quinoline, and isoquinoline in both cyclohexane andp-xylene solution. The data have been used to calculate relaxation times and apparent dipole moments. For phthalazine, quinoline, and isoquinoline in cyclohexane at 50 °C the distribution coefficient is zero and their relaxation times are very similar. Although the axes about which these three molecules may relax lead to different volumes being swept out, no variation in relaxation behavior has been detected, and each system can be characterized by one relaxation time. The relaxation times for all the heterocyclic molecules except quinoline and acridine inp-xylene are appreciably longer than in cyclohexane. Relaxation time values appear a sensitive means of detecting the weak molecular interaction between the amine and thep-xylene. The difference in behavior between the quinoline and acridine as opposed to isoquinoline could be attributed to a more appreciable steric effect in the former two, hindering the approach of the π-electrons of thep-xylene molecules to the hybridized lone pair on the nitrogen atom. No interaction is, in fact, detectable in the case of quinoline and acridine. The importance of allowing for weak intermolecular forces, even in dilute solution, when relaxation values are being anticipated, is emphasized.

ISSN:0008-4042    

DOI:10.1139/v68-388

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

A study has been made of the proton magnetic resonance spectra for all of the Group IVB derivatives of the series MVi4and(= phenyl group and Vi = vinyl group). The spectra were measured at 60 MHz as accurately as possible and the assignment of transitions was checked with a variety of supplemental aids including double irradiation, multiple quantum transitions, and medium effects Final, accurate spectral parameters were derived using both iterative and exact computational methods for solution of the three-spin problem Excellent agreement was obtained between the sets of parameters determined by the two methodsThe chemical shifts for both series of compounds display a number of characteristic trends of which the most notable is a displacement of the vinyl proton signals to low field with increasing atomic number of the M atom In each series the largest shift change is noted in going from the carbon to the silicon derivative These deshieldings have been attributed to the enhanced possibility of dπ–pπinteraction between the central M atom and the vinyl group in higher members of the series Marked changes are also the internal shifts of the vinyl protons down both series of compounds It is concluded that these changes are principally due to the effects of the M—C bond diamagnetic anisotropy The trends in internal shifts can be satisfactorily reproduced by the dipole approximation using Δχ values of 4, 6, 8, 12, and 18 × 10−6 cm3mole−1for the C, Si, Ge, Sn, and Pb–carbon bonds respectivelyThe signals for the vinyl protons of theseries are all located to low field relative to the MVi4series This deshielding is satisfactorily accounted for by the effects of the phenyl ring diamagnetic anisotropy in the former seriesA linear correlation is observed between the sums of the coupling constants and the electronegativities,Em, of the central M atom for both series of compounds However, the ΣJvalues for theseries are all slightly lower than the corresponding sums for the MVi4series, indicating that the electronegativity of the phenyl group is somewhat larger than for the vinyl groupA significant solvent and concentration dependence is only noted for compounds belonging to theseries For example, thetransproton ofshifts up-field by 4 Hz while thecisproton is displaced down-field by 4 Hz as the concentration ofis increased to 50 mole % in carbon tetrachloride These changes have been interpreted on the basis of a solute–solute interaction scheme of the type proposed previously for phenyl proton shifts.

ISSN:0008-4042    

DOI:10.1139/v68-389

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

Stability constants have been measured spectrophotometrically for the 1:1 complexes of iron(III) with phenol and five derivatives in background solutions having two different compositions, 0.027 MNaClO4and 0 5 MKNO3Conditional acidity constants for these phenols in the second of these media were also determined The experimental results were treated in two different ways to obtain values of the equilibrium constants and the molar extinction coefficients of the complexes It is apparent that the equilibrium in these cases must be studied under conditions, such as low pH and low concentration of iron, which militate against good precision in the results

ISSN:0008-4042    

DOI:10.1139/v68-390

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

An attempt has been made to study the influence of lone pair electrons on the potential constants of BrF5with a modified Urey–Bradley force field. It is found that the lone pair – bond pair repulsion is greater than the bond pair – bond pair repulsion. It is also concluded from a study of other molecules containing halogen atoms that the ratio of lone pair – bond pair interaction to bond pair – bond pair interaction is very nearly 1.23.

ISSN:0008-4042    

DOI:10.1139/v68-391

出版商:NRC Research Press    

年代:1968

数据来源: NRC

摘要:

The following properties have been investigated experimentally: density, change of volume on mixing, vapor pressure, surface tension, and viscosity, at temperatures above and below the critical solution temperature. The question at issue is: How does the chemical potential, or any property dependent on chemical potential, change, at constant temperature, over a range of composition, just above the critical solution temperature? In the present case, the vapor pressure and surface tension, properties directly dependent on chemical potential, are constant within the range of experimental accuracy (which, however, may not be sufficient) over a range of concentration. The viscosity is complicated by the occurrence of anomalous viscosity. The change of volume on mixing is negative, and this is usually associated with compound formation. In all other systems investigated by us, except the system triethylamine–water, ΔVis positive. We have shown elsewhere, however, that a very stable chemical compound is formed between water and triethylamine.

ISSN:0008-4042    

DOI:10.1139/v68-392

出版商:NRC Research Press    

年代:1968

数据来源: NRC