Hydrophile lipophile balance of hydroxyoximes in McGowan scale and their partition and extraction properties

Hydroxyoxime hydrophobicity was characterized by hydrophile lipophile balance in McGowan scale, and the relationship's log partition coefficient vs HLB^Ga and extraction rate vs HLB^Ga were discussed. The effect of the alkyl length and structure upon hydroxyoxime hydrophile lipophile balance and partition coefficients can be qualitatively considered using the effective length of the alkyl. The partition data for homologous series can be predicted from HLB^Ga. Relationships between extraction rate and HLB^Ga do not support the traditional view of the extraction mechanism. It supports the idea of the mechanism change from the bulk aqueous to the interfacial mechanism with the increase in hydroxyoxime hydrophobicity.     

SEMI-EMPIRICAL (PM3) COMPUTATIONAL STUDIES OF THE ASSOCIATION OF ALKYL PYRIDINE MONOCARBOXYLATES WITH METHANOL AND WATER IMPLICATION FOR INTERFACIAL ACTIVITY AND THE EFFECT OF PHASE MODIFIERS

ABSTRACT

Alkyl pyridine monocarboxylates can form associates with alcohols. The alcohol hydroxyl group is mainly bonded with oxygen atoms of the ester group, while the pyridine nitrogen is only slightly blocked. The degree of hydrogen-bonding at the different acceptor sites depends significantly on the position of the carboxyl group in the pyridine ring. Alkyl pyridine monocarboxylates can form hydrates with water molecules. Again the hydrogen bonds are mainly formed with the oxygen atoms of the ester group. Such hydration is limited in extraction systems containing alkyl isonicotinate and alkyl nicotinate, and only weak monohydrates with one water molecule bonded with the pyridine nitrogen can be formed. The oxygens of the ester group of alkyl picolinate can be, however, easily hydrated. This phenomenon is reflected in interfacial activity and interfacial concentration of the considered extractants.     

Plasma enhanced aerosol–gel deposition of Al2O3 coatings

The new plasma enhanced aerosol–gel technique has been used for alumina films preparation, in this work. This process integrates aerosol–gel deposition of films and their plasma treatment in one reactor. The alumina films deposited by aerosol–gel method on Si substrate were plasma or thermally treated. The influence of deposition and condensation conditions on properties of the films was studied. Produced coatings were characterized in terms of surface morphology (SEM, AFM) as well as crystalline and chemical structure (FTIR, XRD). Plasma discharge used for modification of the substrates prior to the deposition process improved homogeneity of produced coatings. Coatings obtained at room temperature exhibit boehmite structure which was transformed into γ-Al₂O₃ after annealing. A similar transformation was induced by low temperature oxide plasma discharge treatment for sufficiently thin coatings.     

Synthesis and bactericidal properties of some pyridinium chlorides with alkylthiomethyl hydrophobic groups

Alkylthiomethyl chlorides were synthesized via the reaction of thioalcohols with paraformaldehyde and hydrogen chloride. The optimum reaction parameters were determined. Alkylthiomethylpyridinium chlorides were synthesized via the reaction of ocytlthiomethyl or dodecylthiomethyl chlorides with pyridine and its methyl derivatives. The surface active properties and its methyl derivatives. The surface active properties and minimum inhibitory concentrations (M.I.C.) toward various strains of microorganisms were determined for the compounds synthesized. It was found that they exhibit better bactericidal activity than commercial cetylpyridinium and cetyl-trimethylammonium bromides.     

Photo-induced properties of thin TiO2 films deposited using the radio frequency plasma enhanced chemical vapor deposition method

Thin titanium oxide films were deposited with the help of radio frequency plasma enhanced chemical vapor deposition technique. The RF power of deposition was applied as the operational parameter of the process, and optical properties, transmittance in particular, of the films were utilized as criterion for their selection.Photo-induced properties of the films, including a change of water wettability under the effect of illumination and photocatalytic activity, were studied. A substantial decrease of water contact angle was observed upon the irradiation of the films with ultraviolet (UV) light. The largest increase of water wettability was obtained for the surfaces of the films exhibiting the highest value of index of refraction. Testing of the photo-catalytic activity of the titanium oxide films comprised UV light-induced decomposition of benzene and aniline dissolved in water and bactericidal action against the Escherichia coli strain DH5α. The largest bactericidal efficiency was observed in the case of the film characterized by the highest index of refraction. Auger Electron Spectroscopy measurements have shown that the film composition is that of a nearly stoichiometric TiO₂, with a small chlorine contamination.     

Processing of interfacial tension data in solvent extraction studies. Interfacial properties of various acidic organophosphorus extractants

Basically, the interfacial tension data can be plotted as a function of logarithm C where C denotes the concentration of any form of the surface active species considered. The various relationships y vs In C are discussed here from a mathematical point of view and it is shown that ambiguities may arise from the use of the interfacial tension curves versus the total extractant concentration for the interfacial tension data interpretation. The method recommended in this work is based on the computation of the whole surface excess curves (Γ vs concentration of individual species). This is achieved by matching various adsorption equations (e.g. Szyszkowski or Temkin relationships) or empirical equations to the interfacial tension data (y vs C). The term dy/dln C can then be analytically calculated and introduced into the Gibbs equation [Γ = ?(1/RT)dy/dln C] to derive mathematical expressions for the surface excess curves. To exemplify our approach, interfacial data are interpreted for dibutylphosphoric acid (HDBP), di(2-ethylhexyl)phosphoric acid (HDEHP), di(hexoxyethyl)phosphoric acid (HDHOEP), 2-ethylhexyl-2-ethylhexylphosphonic acid (HEH[EHP]) and di(2-ethylhexyl)phosphinic acid (H[DEHP]) at various liquid-liquid interfaces.     

Alcoxymethyl Ethers of Glucose and Its Oligomers Part I. Synthesis of Alcoxymethyl Glucose Ethers

The reaction between glucose and alcoxymethyl chlorides containing from 3 to 12 carbon atoms in alkyl group was investigated. The composition of the reaction products was determined. The influence of reaction parameters on reaction course was discussed.     

Alcoxymethyl Ethers of Glucose and Its Oligomers Part II. Composition and Structure of Alcoxymethyl Glucose Ethers

Dodecoxymethyl glucose ethers were separated by TLC and column chromatography and the main components were identified. The fraction of monododecoxymethyl glucose ethers was separated into positional isomers. The reactivity of hydroxyl groups of glucose in the reaction with dodecoxymethyl chloride was investigated.     

Polarity of Some Oxime Extractants as determined by gas-liquid-chromatography

The polarity index, retention index, coefficient ϱ and partial Gibbs function of one mole of a solute methylene group and the Sevcik A criterion were determined at different temperatures for some aromatic hydroxyoximes and intermediate ketones by means of gas-liquid chromatography using n-alkanes as nonpolar agents and n-alcohols as polar agents. The relations between these parameters and the relations between the polarity and the compound structure were discussed. In the oxime and ketone molecules the polarity of the hydrophilic groups changes in the following order:  OH>NOH> O ;and  OH> CO> O , respectively. The ketones have less polarity than the oximes. The phenolic hydroxyl group has twice the polarity of the oxime and the carbonyl groups. The chlorine atom at the ortho position in relation to the hydroxyl group sharply increases the polarity.