Solutions In Polar Solvents Research Articles

Extrapolation method for the determination of electric dipole moments from solutions in polar solvents

Methode d'extrapolation s'appuyant sur l'equation d'Onoager. Application aux mesures de constantes dielectriques de dichloro-1,1 ethane et nitrobenzene dans divers solvants polaires. Resultats corrects pour les solvants fortement polaires, apolaires et intermediaires

Formation of the colored merocyanine form of indoline spiropyranes in pulse radiolysis of their solutions in polar solvents

Formation of the colored merocyanine form of indoline spiropyranes in pulse radiolysis of their solutions in polar solvents

Oxidation of alkoxyphenols. Part 26. The trimer of a 2,2′-diphenoquinone (1,1′-bicyclohexa-3,5-dienylidene-2,2′-dione)

The blue material produced in the oxidation of 4-methoxy-3-t-butylphenol, formerly described as an intermediate in the formation of the dibenzo[d,f][1,3]dioxepin oxidation product, is shown to be 5,5′-dimethoxy-4,4′-di-t-butyl-2,2′-diphenoquinone. This quinone spontaneously condenses to a colourless trimer which, in solution in polar solvents, is shown to be in equilibrium with free radicals derived from the monomer and a dimes; that from the former regenerates the quinone. The crystal structure of the dimes has been determined as 1′-(2-hydroxy-5-methoxy-4-t-butylphenyl)-4a′,5,7′-trimethoxy-4,4′-6′-tri-t-butylspiro(cyclohexa-3,5-diene-1,9′-xanthen)-2,2′(4′aH)-dione.

The effect of solvent environment on molecular electronic oscillator strengths

A simple expression is derived for the effect of solvent environment on solute oscillator strength. The only parameters required are the refractive index of the solvent and a geometric factor which depends upon the shape of the molecule and the orientation of its transition moment. Whereas classical local field theories predict that oscillator strengths in all molecules should change in the same direction with increasing solvent polarizability, our theory correctly predicts a decrease in the oscillator strength of the π*←π transition of β-carotene and an increase in the oscillator strength of the π*←n transition in pyrazine. The theory is based on perturbation of the ground and excited states of the solute by point–dipole interactions between solvent and solute transition moments. Although our expression is derived for nonpolar solutes in nonpolar solvents, experimental evidence indicates that it may be equally applicable to nonpolar solutes in polar solvents.

Antifungal Properties of Some N,N-Dialkyloxamides

AbstractN,N-Dialkyloxamides show potent antifungal activity against Pityrosporum ovale when used as solutions in polar solvents. The antifungal activity deteriorates rapidly due to decomposition of the oxamides in solution

Excess Thermodynamic Quantities of Aromatic Hydrocarbon Solutions in Polar Solvents, Determined by Rayleigh Light Scattering

Excess Thermodynamic Quantities of Aromatic Hydrocarbon Solutions in Polar Solvents, Determined by Rayleigh Light Scattering

COMPLEXES OF TRIVALENT PHOSPHORUS DERIVATIVES, XVIII. SOME COMPLEXES OF NEOPENTYLPHOSPHINES WITH RHODIUM, NICKEL, AND PALLADIUM CHLORIDES1

Abstract Trineopentylphosphine reacts with hydrated rhodium(III) chloride to give yellow ([(Me3CCH2)3P]2 RhCl2)2 in ethanol at room temperature but yellow [(Me3CCH2)3P]2 Rh(CO)Cl in boiling ROCH2CH2OH (R = CH3 or C2H5). Dineopentylphenylphosphine reacts with hydrated rhodium(III) chloride in ethanol to give red [(Me3CCH2)2PC6H5]3Rh2Cl4 at room temperature and orange ([(Me3CCH2)2PC6H5]2RhCl2)2 at the boiling point. Neither trineopentylphosphine nor dineopentylphenylphosphine reacts with nickel(II) chloride in ethanol solution. However, neopentyldiphenylphosphine reacts with nickel(II) chloride in ethanol solution to give purple [Me3CCH2P(C6H5)2]2NiCl2, which gives yellow solutions in polar solvents. Trineopentylphosphine reacts with palladium(II) chloride derivatives in boiling n-butanol to give either yellow [(Me3CCH2)3P]2PdCl2 or orange [(Me3CCH2)3PPdCl2]2 depending upon the reaction conditions.

A simple molecular model of adsorption chromatography

A molecular model of adsorption elaborated for silica was applied to the analysis of chromatographic results obtained for nitro derivatives of benzene, naphthalene and biphenyl using thin layers of magnesium silicate and Florisil developed with solutions of polar solvents in cyclohexane. In most of cases the RM values were linearly related to the logarithm of the mole fraction of the polar solvent; this is characteristic of the adsorption mechanism involving mutual displacement of solute and solvent molecules in agreement with the law of mass action. The molecular structure effects are discussed and the slopes of the linear plots interpreted in terms of the presumed configuration of the adsorbed molecules.

Ordered copolyamide‐imides and copolyester‐imides

AbstractA group of copolyamide‐imides and copolyester‐imides completely ordered has been obtained by the reaction of aliphatic and aromatic diamines with symmetrical monomers possessing reactive imide group.The aromatic diimide‐amide and diimide‐ester monomers were prepared by means of the reaction of acidolysis between trimellitic acid imide and acetoxy derivative of aromatic diamines and diphenols.The diimide‐ester monomers with aliphatic substitutes were obtained by ester interchange between glycols and the methyl ester of trimellitimide.The polymerization reactions were carried out in a solution of polar solvents and the solated polymers were characterized with the object of estabilishing a relation between the properties and the structure of each one.

Electric permittivities and dipole moments of solutes in polar solvents

Equations based upon the approaches of Debye, Onsager, Weaver and Parry and Buckingham are developed for calculating the electric dipole moments of polar solutes in polar solvents and employed for 21 solutes in benzene, chlorobenzene and ethyl acetate solutions. Consistent results are obtainable from the measurements made in the non-polar and both polar solvents.

Infrared spectra and structure of substituted unsaturated carbonyl compounds: XII. β-Aminoacrolein

The IR spectra of β-aminoacrolein, the simplest amide vinylogue, have been studied. The solid compound has the trans configuration and this form prevails in solution in polar solvents. Of the two rotational isomers of the trans form, the s-trans seems to predominate in solution. In chloroform and other non-polar solvents, intense bands of the cis form were observed after the trans-cis equilibrium had been established. The band pattern of the cis form is very similar to that of cis-enamino ketones. The absorption bands were assigned on the basis of deuterium substitution and by comparison with previous data on alkylaminoacroleins.

Ultrasonic Absorption in Propionic Acid

The ultrasonic relaxational absorption in methyl propionate solutions of propionic acid has been studied in the frequency range 0.5–95 Mc/sec at concentrations varying from 0 to 1 mole fraction. The relaxation frequencies are 1.8, 2.2, 2.8, and 3.4 Mc/sec independent of the concentration at 20°, 25°, 30°, and 35°C, respectively. The independence of fmax on the concentration indicates that the ultrasonic relaxational absorption is associated with the uni—unimolecular reaction. The kinetic values have been calculated for the uni—unimolecular reaction by Tabuchi's theoretical equations. The forward and backward rate constants are 2.3×105 and 1.06×107 sec−1 at 20°C for pure propionic acid, respectively, and the heat of reaction is 4.7 kcal/mole of dimer. The value of Cpr is equal to that of Cvr, since the volume change resulting from reaction is absent. The consideration for the type of reaction, the magnitude of heat of reaction, and no volume change associated with reaction have led us to the conclusion that the ultrasonic absorption in propionic acid is associated with a breakage of one of two hydrogen bonds. The solvent effect on the relaxation mechanism has also been studied in various solvent solutions of propionic acid. The relaxation frequency fmax does not change with increasing concentration in polar solvent solutions, whereas it decreases with increasing concentration in nonpolar solvent solutions.

Scission of the carbon-carbon bond in compounds containing the triphenylmethyl group

1. Absorption spectra were measured for 3,3,3-tris(p-dimethylaminophenyl)propionaldehyde, allyltris(p-dimethylaminophenyl)methane, and tris(p-dimethylaminophenyl)prophylmethane as solutions in polar solvents and after interaction with acetic, chloroacetic, and trichloroacetic acids. 2. On the basis of the phospectrometric data it was shown that scission of a C-C bond occurs in the first two compounds under the action of acids and polar solvents, but in the third only under the action of acids. 3. It was shown how the scission of the C-C bond depends on the character of the conjugation in the molecules of the compounds investigated.

The calculation of true dipole moments form solutions in Polar Solvents

The theory presented in an earlier paper is here developed as a method for the evaluation of' true dipole moments from data obtained from solutions in polar solvents. As illustrations, the new method is applied to values relating to solutions of several substances in chloroform, chlorobenzene, and nitrobenzene. The results, considering the nature of the problem, are satisfactory. The accuracy is greatest when the solute is highly polar and the dielectric constant of the solvent small. Aqueous solutions of pyridine and of two amino acids are also considered. In the latter cases especially, the predicted dipole moments agree most favourably with anticipated values obtained for the zwitterions by multiplying the electronic charge by the expected charge separation.