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    Excess molar volumes of binary mixtures (an ionic liquid + water) : A review
    (Elsevier, 2015-03) Bahadur, Indra; Singh, Sangeeta; Redhi, Gan G.; Venkatesu, Pannuru; Letcher, Trevor M.
    This review covers recent developments in the area of excess molar volumes for mixtures of {ILs (1) + H2O (2)} where ILs refers to ionic liquids involving cations: imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium and ammonium groups; and anions: tetraborate, triflate, hydrogensulphate, methylsulphate, ethylsulphate, thiocyanate, dicyanamide, octanate, acetate, nitrate, chloride, bromide, and iodine. The excess molar volumes of aqueous ILs were found to cover a wide range of values for the different ILs (ranging from −1.7 cm3 · mol−1 to 1.2 cm3 · mol−1). The excess molar volumes increased with increasing temperature for all systems studied in this review. The magnitude and in some cases the sign of the excess molar volumes for all the aqueous ILs mixtures, apart from the ammonium ILs, were very dependent on temperature. This was particularly important in the dilute IL concentration region. It was found that the sign and magnitude of the excess molar volumes of aqueous ILs (for ILs with hydrophobic cations), was more dependent on the nature of the anion than on the cation.
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    An evaluation of the efficacy of using selected solvents for the extraction of lipids from algal biomass by the soxhlet extraction method
    (Elsevier, 2013-08-14) Ramluckan, Krishan; Bux, Faizal; Moodley, Kandasamy G.
    The use of solvents for the extraction of lipids from algal biomass has been a method of choice for many years. The soxhlet extraction method was chosen because of its simplicity in operation, relative safety and potential for upscaling to industrial plant level. The source of algal biomass was a raceway pond. Chlorella sp. which is known to produce larger amounts of oil than other indigenous species was used for this investigation. Thirteen solvents spanning a range of polarities and solubilities were selected for this study. Extraction methodology involved the use of single solvents, selected binary solvent mixtures and time-based extractions which were varied from 1 to 5 h. Ultraviolet (UV) spectroscopy was used to determine chlorophyll content of the lipid extracts and gas chromatography was used for the identifica-tion and quantitation of the lipids. Analysis showed that ethanol, chloroform and hexane were generally more efficient in the extraction of lipids than the other solvents studied, producing lipid contents in excess of 10%. The time-based trials indicated that the optimum extraction time was 3 h for the solvents selected. The binary solvent mixture with the greatest extraction efficiency (i.e. >10% lipid extract) was obtained with the 1:1 mixture of chloroform:ethanol. Chlorophyll quantities varied for each solvent extract with chloroform and methanol producing the highest values at >1%. Chromatography was effec-tive in identifying lipids used in the production of biodiesel.