To facilitate urine sample preparation prior to head-space gas-chromatographic (HS-GC) analysis. Urine samples containing one of the five solvents (acetone, methanol, methyl ethyl ketone, methyl isobutyl ketone and toluene) at the levels of biological exposure limits were aspirated into a vacuum tube via holder, a device commercially available for venous blood collection (the vacuum tube method...

In the present study, a new series of 2,6-diaryl-3-methyl-4-piperidones was synthesized by Mannich reaction (condensation) of ethyl-methyl ketone, substituted aromatic aldehydes and ammonium acetate. Oximes and thiosemicarbazone derivatives of 2,6-diaryl-3-methyl-4-piperidones were synthesized by reaction with hydroxylamine hydrochloride and thiosemicarbazide respectively. The chemical structur...

2-(4-Chloro-phen-yl)-2-oxoethyl 3-bromo-benzoate, C15H10BrClO3, was synthesized in a single-step reaction by condensation of 3-bromo-benzoic acid with 2-bromo-1-(4-chloro-phen-yl)ethanone in di-methyl-formamide in the presence of tri-ethyl-amine as a catalyst. The structure consists of an aryl ketone moiety linked to an aryl ester unit by a methyl-ene group. Both units are reasonably planar (r....

Group contribution methods such as the UNIFAC are very useful to researchers and engineers involved in synthesis, feasibility studies, design and optimization of separation processes. They can be applied successfully to predict phase equilibrium and excess properties in the development of chemical and separation processes. The main focus of this work was to investigate the possibility of absorb...