Fatty Acid Methyl Esters as Biosolvents of Epoxy Resins: A Physicochemical Study

The C8 to C18 fatty acid methyl esters (FAME) have been compared as solvents for two epoxy resin pre-polymers, bisphenol A diglycidyl ether (DGEBA) and triglycidyl paminophenol ether (TGPA). It was found that the solubilization limits vary according to the ester and that methyl caprylate is the best solvent of both resins. To explain these solubility performances, physical and chemical properties of FAME were studied, such as the Hansen parameters, viscosity, binary diffusion coefficient and vaporization enthalpy. Determination of the physicochemical parameters of FAME was carried out by laboratory experimentations and by calculation from bibliographic data. The Hansen parameters of FAME and epoxy resins pre-polymers were theoretically and experimentally determined. The FAME chain length showed a long dependence on the binary diffusion parameters and kinematic viscosity, which are mass and momentum transport properties. Moreover, the vaporization enthalpy of these compounds was directly correlated with the solubilization limits

Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context

This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals

Improvement of physicochemical parameters of acyclovir using cocrystallization approach

ABSTRACT Acyclovir is an antiviral drug having potent activity against the virus of herpes family and varicella zoster. Unfortunately, drug suffers very poor oral bioavailability (15-30%). The main objective of present study was to develop acyclovir cocrystals with improved solubility which may result in improvement of bioavailability. Hansen solubility approach was used as a tool to predict the cocrystal formation of a drug with selected coformer. Cocrystals of acyclovir with various coformers were screened in order to enhance their water solubility. Cocrystals of the drug were prepared using various methods like solvent evaporation, wet grinding, and antisolvent addition. Formation of cocrystals by solvent evaporation method was found to be better method amongst all. Optimization of cocrystal formation was carried out by employing different solvents as well as the stoichiometric ratio of acyclovir with that of coformer. Synthesis of cocrystals was optimized using water as a solvent system resulted in good agreements. The potential cocrystal formation of acyclovir was characterized by IR, PXRD and DSC techniques. An in-vitro dissolution study was performed to determine the dissolution rate of cocrystals. The results suggest that acyclovir forms cocrystals with tartaric acid and the initial dissolution rate of synthesized cocrystals were considerably faster as compared to pure acyclovir

De geïnduceerde pyrolyse van methaan

Applied Science

The wet purification of coal gas and similar gases by the Staatsmijnen-Otto-Process.

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