Molecular structure of phosgene as studied by gas electron diffraction and microwave spectroscopy: The rz structure and isotope effect

The r_z structure of phosgene has been determined by a joint analysis of the electron diffraction intensity and the rotational constants as follows: $\text{r}{}_{\mathrm{z}}\text{(}\text{CO}\text{) = 1.1785 ± 0.0026}\text{A}\text{?}$, $\text{r}{}_{\mathrm{z}}\text{(}\text{CCl}\text{) = 1.7424 ± 0.0013}\text{A}\text{?}$, ∠_z;ClCCl = 111.83 ± 0.11°, where uncertainties represent estimated limits of experimental error. The effective constants representing bond-stretching anharmonicity have been obtained from an analysis of the isotopic differences in the r_z structure: $\text{a}{}_3\text{(}\text{CO}\text{) = 2.9 ± 0.9}\text{A}\text{?}{}^{\mathrm{?1}}$, $\text{a}{}_3\text{(}\text{CCl}\text{) = 1.6 ± 0.4}\text{A}\text{?}{}^{\mathrm{?1}}$. The equilibrium bond distances have been estimated from the r_z structure for the normal species and from the anharmonic constants to be $\text{r}{}_{\mathrm{e}}\text{(}\text{CO}\text{) = 1.1756 ± 0.0032}\text{A}\text{?}$, $\text{r}{}_{\mathrm{e}}\text{(}\text{CCl}\text{) = 1.7381 ± 0.0019}\text{A}\text{?}$.     

Non-Newtonian flow curves including lower and upper Newtonian regions for dilute and moderately concentrated polystyrene solutions

The non-Newtonian viscosity in steady flow was measured for solutions of polystyrene (M?_w/M?_n = 1.1) in diethyl phthalate at 30.0°C. In the moderately concentrated solutions, from 6.03 × 10^?2 to 5.62 × 10^?1g/cm³, the viscosity data modified by frictional parameters fit the Graessley theoretical curve for a narrow distribution polymer. The dilute solutions, from 3.26 × 10^?3 to 1.57 × 10^?2 g/cm³, were nonentangled systems whose non-Newtonian properties could be explained by the excluded volume effect as proposed by Fixman. On the basis of the non-Newtonian data, it was concluded that the solution of 3.30 × 10^?2 g/cm³ was a lower critical entanglement concentration, which was distinguished from the usual higher critical concentration for entanglement. This lower critical concentration was also found in the concentration dependence of the activation energy of flow and the absorbance at 310 nm.     

Negative ion mass spectra of salicylaldehydato and 2-hydroxy-1-naphthylaldehydato complexes of Co(II), Ni(II) and Cu(II): Consecutive and competitive eliminations of CO and H2CO

The negative ion mass spectra of some divalent metal complexes, ML₂, have been measured, where M?Co, Ni and Cu, and LH = salicylaldehyde or 2-hydroxy-1-naphthylaldehyde. All compounds yield intense molecular anions. The mass spectra of these compounds suggest that consecutive and competitive eliminations of CO and H₂CO, and various types of hydrogen migrations are involved in the fragmentation of the molecular anions. The mechanism of the fragmentation process and metastable peaks observed are also discussed.     

Non-Newtonian behavior in steady flow over the range from the lower to the upper Newtonian region for polystyrene solution

Graessley's entanglement theory of viscosity modified by a frictional viscosity parameter η_fric is applied to data on solutions of polystyrene in diethyl phthalate at various concentrations and different temperatures. All the data modified give a single master curve over the entire rates of shear, as obtained previously with polydimethyl-siloxanes of various molecular weights and their solutions of various concentrations. The zero-shear viscosity η₀, the upper Newtonian viscosity η_∞, and η_fric are compared. Three activation energies for flow are estimated from η₀, η_∞ and η_fric, and are compared. The result suggests that the flow behavior in the upper Newtonian region is much more dependent on η_fric than on the entanglement viscosity term η_ent. The ratio of zero-shear entanglement viscosity η_ent,0 to η_fric can be used as a measure of the non-Newtonian behavior of the present solutions. Non-Newtonian behavior of the investigated polymer solution becomes appreciable at about η_ent,0/η_fric = 2.5. These results are in agreement with previous conclusions based on comparison between η₀, η_∞ and η_fric for polydimethyl-siloxanes and their solutions.