Tel: (33) 5 62 88 58 26 ; fax: (33) 5 62 88 58 29Accepted for publication in Chemical Engineering & Processing
Abstract.In this article, a systematic study of the separation of the n-hexane -ethyl acetate mixture with an entrainer by heterogeneous azeotropic batch distillation is performed. Based upon the thermodynamic behaviour of the ternary mixtures, potential entrainers partially miscible with one or two original azeotropic components are chosen. In all cases, the entrainer adds a heterogeneous binary or ternary azeotrope that is the lowest boiling point in the ternary diagram. Therefore, it leaves the column by the overhead stream which is subcooled to get two liquid phases in the decanter. The phase with the highest amount of the original component is removed as distillate product whereas the entrainer -rich phase is continuously refluxed to the column. Considering methanol, acetonitrile, water and nitromethane as heterogeneous entrainers, screening was performed based on the 2 composition of the unstable heteroazeotropic mixture, the ratio of both liquid phases in the condensed top vapour and the purity of the distillate product determined by the liquidliquid envelope at the decanter temperature. The process feasibility analysis is validated by using rigorous simulation with the batch process simulator ProSimBatch. Simulation results are then corroborated in a bench experimental column for the selected entrainer, showing several advantages of heterogeneous batch distillation compared to homogeneous systems.
Mangiferin, a bioactive metabolite having potent antioxidant and pharmacological properties has been obtained in this work by microwave assisted extraction (MAE) technique, from Mangifera indica leaves. A BoxBehnken design was used to evaluate the effect of three parameters: microwave power, the time of extraction, and the ratio of solvent to raw material (mL/g) over the mangiferin yield. Irradiation time was the most important parameter on the recovery of mangiferin. The results indicated that the optimal conditions should be as follows: power of microwave 900 W, extraction time of 5 min and a solvent volume / vegetal material relation of 10. With these parameters the maximum mangiferin yield was 63.22%. The MAE process was compared with the conventional extraction in stirred tank. No significant statistical differences were found (p= 0.5639) between both extraction methods of mangiferin. The presence of the metabolite was confirmed using high performance liquid chromatography. The method was validated with the guidelines set on the International Conference on Harmonization (ICH), for the validation of analytical procedures.
The water sorption isotherms of the Erythrina fusca Lour bark at 30 and 40 C were determined over relative humidity ranging from 55 to 85%. The equilibrium moisture content was determined gravimetrically. The moisture sorption isotherms showed that the equilibrium moisture decreases with increase of temperature. Six models were used for to fit the experimental curves of equilibrium humidity. Parameters of each equation were determined by nonlinear regression analysis. The isosteric heat of moisture sorption was calculated using the Claussius-Clapeyron equation.
The solubility of cefotaxime sodium salt (sodium
(7R)-7-[(Z)-2-(2-aminothiazol-4-yl)-2-(methoxyimino)acetamido]cephalosporanate) in methanol, ethanol, acetone,
n-hexane, dichloromethane, diethyl ether,
and ethyl acetate in the temperature range from 5 to 40 °C was
determined.
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