Thermochemistry of nonaqueous solutions of electrolytes: II. Heat of solution of sodium iodide in water-dioxane

The heats of solution of sodium iodide in water and water-dioxane (45. 95, 52. 55, and 68. 15% by wt dioxane at 25° (also for 2° for the first of these mixtures) are reported. The process becomes more exothermic as the dioxane content increases; a qualitative interpretation. The temperature coefficient of the integral heat is zero at 2–25°C for 45. 95 % by wt dioxane. The initial heats of solution of NaI at 25° in water and the mixtures are –1. 81, –4. 99, –5. 39, –6. 63 kcal/mole and bear a linear relation to the composition and dielectric constant of the solvent.     

Modeling variations in near-infrared spectra caused by the coherent backscattering effect

We study a new optical effect, a spectral manifestation of coherent backscattering, which reveals itself as systematic variations in the depth of absorption bands with changing phase angle. We used Cassini VIMS near-infrared spectra of Saturn's icy satellite Rhea in order to identify and characterize the spectral change with phase angle, focusing on the change in the depth of water-ice absorption bands. To model realistic characteristics of the surfaces of icy satellites, which are most likely covered by micron-sized densely packed particles, we perform simulations using a theoretical approach based on direct computer solutions of the macroscopic Maxwell equations. Our results show that this approach can reproduce the observed phase-angle variations in the depth of the absorption bands. The modeled changes in the absorption bands are strongly affected by physical properties of the regolith, especially by the size and packing density of the ice particles. Thus, the phase-angle spectral variations demonstrate a promising remote-sensing capability for studying properties of the surfaces of icy bodies and other objects that exhibit a strong coherent backscattering effect.     

Nanobiocomposite based on selenium and arabinogalactan: Synthesis,structure, and application

Russian Journal of General Chemistry - Nanocomposite of heteropolysaccharide arabinogalactan and elemental selenium (0.54% of Se) has been prepared and studied by means of transmission electron...     

Reactivity of Functionalized Phosphonates 1. Acid-Base Properties and Reactivity of Methyl Esters of Alpha-Aminophosphonic Acids

Acid-base properties and reactivity of series of alpha-aminophosphonates has been investigated. The reaction of addition of the aminophosphonates to phenylisocyanate was used as a model reaction. The influence of steric and electronic effects of substituents at alpha-carbon or nitrogen in amino group on the mechanism inversion from AdN to AdE is discussed.     

Nucleophilic addition of phosphine to 4-chlorostyrenes in the KOH-DMSO system

In the superbasic system KOH-DMSO (H₂O) at 60–75 °C (2–2.5 h, atmospheric pressure), 4-chlorostyrene and 4-chloro-α-methylstyrene add phosphine at the double bond to form 1: 1 and 2: 1 anti-Markovnikov adducts in 10–18% and 58–67% yields, respectively.     

Approximate calculation of coherent backscattering for semi-infinite discrete random media

We describe an approximate method for the calculation of all characteristics of coherent backscattering for a homogeneous, semi-infinite particulate medium. The method allows one to transform a system of integral equations describing coherent backscattering exactly into a system of linear algebraic equations affording an efficient numerical solution. Comparisons of approximate theoretical results with experimental data as well as with benchmark numerical results for a medium composed of nonabsorbing Rayleigh scatterers have shown that the method can be expected to give a good accuracy.