Effect Of Ethanol Solvent Research Articles

Studies of Solvent Effect of Aquo-Methanol Solvent System on Kinetics and Activation Parameters of Base Catalised Hydrolysis of Ethyl Cinnamate

The solvent effect of ethanol on the alkali catalyzed solvolysis reaction was studied by carring out of the hydrolysis of ester namely ethyl cinnamate in water-methanol media of varying composition consisting of 30 to 70% of methanol (v/v) at different Temperature ranging from 20°C to 70°C. The Specific rate constant values of the reaction were found to depleted with increasing concentration of methanol in reaction media. Enhancement in ΔG* with simultaneous depletion in ΔH* and ΔS* of the reaction, it has been concluded that reaction is enthalpy stimulating and entropy inhibiting and specific salvation take place in water- methanol media. From the evaluated value of Iso kinetic temperature, which is less than 300 indicates that this reaction in water-methanol media obey Barclay-Butler rule and there is weak but considerable solvent –solute interaction taking place in reaction media.

Kinetics and Solvent Effect in Hydrolysis of Ethyl Cinnamate in Water- Methanol Mixture

The solvent effect of ethanol on the alkali catalyzed solvolysis reaction was studied by carring out of the hydrolysis of ester namely ethyl cinnamate in water-methanol media of varying composition consisting of 30 to 70% of methanol (v/v) at different Temperature ranging from 20°C to 70°C. The Specific rate constant values of the reaction were found to depleted with increasing concentration of methanol in reaction media. Enhancement in ΔG* with simultaneous depletion in ΔH* and ΔS* of the reaction, it has been concluded that reaction is enthalpy stimulating and entropy inhibiting and specific salvation take place in water- methanol media. From the evaluated value of Iso kinetic temperature, which is less than 300 indicates that this reaction in water-methanol media obey Barclay-Butler rule and there is weak but considerable solvent –solute interaction taking place in reaction media.

The solvent effect of ethanol and n-hexane on the hydrolysis of triolein and tributyrin by Candida cylindracea lipase

The solvent effect of ethanol and n-hexane on the hydrolysis of triolein and tributyrin by Candida cylindracea lipase

Structure stability and corrosion inhibition of super-hydrophobic film on aluminum in seawater

A novel and stable super-hydrophobic film was prepared by myristic acid (CH 3(CH 2) 12COOH, mya) chemically adsorbed onto the anodized aluminum surface. The static contact angle for seawater on the surface was measured to be 154°. As evidenced by molecular dynamics (MD) simulations and electrochemical impedance spectroscopy (EIS), the effect of ethanol solvent on the film stability was proved. The surface structure and composition were then characterized by means of scanning electron microscopy (SEM) with energy dispersive X-ray spectrum (EDS) and atomic force microscope (AFM). The electrochemical measurements showed that the super-hydrophobic surface significantly decreased the corrosion currents densities ( i corr), corrosion rates and double layer capacitance ( C dl), as simultaneously increased the values of polarization resistance ( R ct) of aluminum in sterile seawater.

Solvent effect of ethanol on crystallization and growth process of L-histidine polymorphs

The solvent effect of ethanol on precipitation behavior and crystal growth rates of the A and B polymorphs of L-histidine were investigated in aqueous solutions. The fraction of A in precipitates decreases quickly when the volume fraction of ethanol in solvent (VOL) increases above 0.2, and finally pure B is obtained at 0.4 VOL. The transformation rate from B to A decreases with ethanol concentration. The growth rate of B was larger than that of A at the same supersaturation degree in both aqueous and ethanol solutions. However, the growth rates of both polymorphs are almost the same at the same concentration in aqueous solution, corresponding to the precipitation behaviors. In ethanol solutions, the growth rate of B is slightly larger than that of A at the same concentration of 0.2 VOL. However, the growth rate of B is much larger than A at 0.4 VOL. The results indicate that the precipitation behavior is controlled mainly by the relative growth rates of the polymorphs. The change of the growth mechanism with increasing VOL is suggested. The concentration decrease of the conformer which corresponds to A is suggested as responsible for the solvent effect.

The Effect of Methyl Groups on the Optical Absorption of Retinal

To examine the effect of methyl groups on the optical absorption of retinal in ethanol solution, the π-electronic states of desmethyl retinals are calculated by extending our previous LCAO-ASMO-SCF-CI method to include 2 p z - and pseudo π-orbitals in methyl branches of polyene chain. The effect of ethanol solvent is also taken into account in the two ways: (1) the effect is assumed to be implicitly included into the parameters of calculation; (2) the interaction of retinal with its neighboring ethanol molecule is explicitly calculated regarding ethanol as a point-dipole. It is thus shown that the observed λ max 's of desmethyl retinals with all- trans , 9- cis or 11- cis form can reasonably be explained by taking account of the change in structure due to the substitution of methyl group(s) by hydrogen atoms.

CIRCULAR DICHROISM OF COBALT(III) COMPLEXES OF THE TYPE[Co(N)6] CONTAINING BIGUANIDE, AND 2,2′-DIPYRIDYL OR 1,10-PHENANTHROLINE

Abstract Biguanide-diamine mixed complexes of the type [Co(diamine)(Hbg)2]3 and [Co(diamine)2 (Hbg)]3+, where the diamines are 1,10-phenanthroline or 2,2′-dipyridyl, have been prepared and resolved. The absorption and circular dichroism (CD) spectra in water, 0.1 M NaOH aqueous solution, and ethanol are reported. Hydroxide ion affects the CD intensity mainly in the first absorption band region. A marked solvent effect of ethanol was also observed for both absorption and CD spectra especially in the first absorption band region. The absolute configurations for all of these complexes are assigned on the basis of their CD spectra.

Spectrophotometric Determination of Chlorophenols Using the Isosbestic Points of Their Spectra

5-40×10-5M Solutions of 2, 4, 5- and 2, 4, 6-trichlorophenol, and 2, 4-, 2, 5- and 2, 6-dichlorophenol can be accurately determined by the absorbance at the isosbestic points of the longest wavelength, especially in 0.01-0.1M hydrochloric acid and 0.5-2% ethanol. Because at the condition, the isosbestic points are situated at near the maxima of the spectra.And pK' of chlorophenols are determined spectrophotometrically. Some solvent effect of ethanol and water upon the spectra of chlorophenols are examined.