James W. McCargar

THERMOCHEMICAL INVESTIGATIONS OF ASSOCIATED SOLUTIONS: 3. EFFECT OF THE INERT COSOLVENT ON SOLUTE - SOLVENT ASSOCIATION CONSTANTS CALCULATED FROM SOLUBILITY MEASUNNENTS

Abstract Solubility are reported for caracole in binary solvent mixtures containing dibutyl ether with n-hexane, n-heptanes, n-octane, cyclopean, cyclostomes, methylcyclohexane and isooctane at 25°C. The results of these measurements are compared to solution models previously developed for solubility in systems containing specific solute-solvent interactions. A simple stoichiometric compellation model based primarily on specific solute-solvent interactions required two equilibrium constants to mathematically describe the experimental solubilitys in binary deputy ether mixtures. Calculated equilibrium constants in cyclostomes co solvent were significantly different from values for the isooctane co solvent system. In comparison, an expression derived by including nonspecific interaction contributions described the solubility data to within an average absolute deviation of 2% using a single carbazole-dibutyl ether association constant, which varied from KΦ = 22 for n-heptanes to KΦ = 30 for isooctane.

Thermochemical investigations of associated solutions. VI. Mole fraction versus volume fraction based equilibrium constants

Solubilities are reported for carbazole at 25°C in binary mixtures containing dibutyl ether and t-butylcyclohexane. Results of these measurements, combined with literature solubilities for an additional nine systems, are used to test the descriptive ability of two equations derived from the nearly ideal binary solvent model for systems containing specific solute-solvent interactions. Both the volume fraction based and mole fraction based equilibrium constant expressions can describe observed solubilities in all solvent systems studied to within an average deviation of about 2%. Numerical values of the volume fraction equilibrium constant, however, are more independent of the inert hydrocarbon cosolvent.

Thermochemical investigations of associated solutions. 7. Development of solubility expressions based on the huyskens and haulait-pirson definition of solution ideality

Abstract The Huyskens and Haulait-Pirson model is applied to associated solutions. Expressions are derived for the determination of solute-solvent equilibrium constants from solute solubility as a function of solvent composition and the excess Gibbs free energy of the binary solvent mixture. Literature values for the solubility of carbazole in ten binary dibutyl ether + alkane solvent mixtures are used to illustrate the calculational procedure. Equilibrium constants for a presumed carbazole-dibutyl ether complex are functions of both mole and volume fraction compositions, and the numerical values vary slightly for the ten inert cosolvents studied.

Polymer dispersed liquid crystal infrared light shutter

We have developed a polymer dispersed liquid crystal (PDLC) device for operation in the midinfrared region of the electromagnetic spectrum. This device can be incorporated in thermal imaging systems that utilize pyroelectric vidicons for night vision applications. The infrared electro-optic properties of several PDLCs as a function of substrate, droplet size, film thickness, and applied ac voltage are examined using infrared spectroscopy, electro-optic and differential scattering measurements, and static video analysis.

Polymer-dispersed liquid-crystal shutters for IR imaging

Polymer-dispersed liquid crystals (PDLCs) have been developed for modulation of infrared radiation in the 2-5 and 8-14 micrometers wavelength regions. The electro-optic performance of an IR PDLC shutter depends on film thickness, liquid crystal droplet size, and the transparency of the substrates and the PDLC components. The effect of each of these factors on IR electro-optic performance of PDLC films was investigated using double modulation experiments and infrared spectroscopy. The authors have also compared the sensitivity of a pyroelectric vidicon infrared camera using PDLC shutter and a mechanical shutter.

Comment on “a new expression for the combinatorial entropy of mixing in liquid mixtures”

Abstract The solution model proposed by Huyskens and Haulait-Pirson is applied to an associated solution. Expressions based on this model show that the equilibrium constant for complex formation is likely to be a function of both mole and volume fraction compositions.