Kaniki Tumba

A group contribution method for estimation of glass-transition temperature of 1,3-dialkylimidazolium ionic liquids

Glass-transition temperature (Tg) of ionic liquids (ILs) plays a key role in assessment of their potential for electrolyte application purposes. In this communication, a new group contribution model is presented for the prediction of the Tg of 1,3-dialkylimidazolium, a class of ILs, which has great potentialities to serve as electrolyte. To develop this model, the contribution of ILs’ anions and cations is separately considered. This simple model shows a low average relative deviation of 1.94xa0% for a data set including 109 experimental glass-transition temperature.

Can 2-methyl-2-butene and isoprene form clathrate hydrates?

Abstract In order to establish whether 2-methyl-2-butene and isoprene can form hydrates, experimental hydrate dissociation data were measured for the following systems: methaneu2009+u2009water, 2-methyl-2-buteneu2009+u2009methaneu2009+u2009water and isopreneu2009+u2009methaneu2009+u2009water. An isochoric pressure search method was used to perform the measurements in the ranges of (274.6 to 288.3) K and (3.25 to 13.35) MPa. The reported results are discussed in terms of the ability of isoprene (2-methyl-1, 3-butadiene) and 2-methyl-2-butene to interfere with methane hydrate dissociation conditions. It is found that the two C5 hydrocarbons are likely not hydrate formers. However, a further confirmation via appropriate analytical tools is recommended.

Optimisation of Croton gratissimus Oil Extraction by n-Hexane and Ethyl Acetate Using Response Surface Methodology

The extraction of oil from Croton gratissimus seeds was studied using the three-factor five-level full-factorial central composite rotatable design (CCRD) of the response surface methodology (RSM). The effect of the three factors selected, viz., extraction time, extraction temperature and solvent-to-feed ratio on the extraction oil yield was investigated when n-hexane and ethyl acetate were used as extraction solvents. The coefficients of determination (R2) of the models developed were 0.98 for n-hexane extraction and 0.97 for ethyl acetate extraction. These results demonstrated that the models developed adequately represented the processes they described. From the optimized model, maximum extraction yield obtained from n-hexane and ethyl acetate extraction were 23.88% and 23.25%, respectively. In both cases the extraction temperature and solvent-to-feed ratio were 35°C and 5 mL/g, respectively. In n-hexane extraction the maximum conditions were reached only after 6 min whereas in ethyl acetate extraction it took 20 min to get the maximum extraction oil yield. Oil extraction of Croton gratissimus seeds, in this work, favoured the use of n-hexane as an extraction solvent as it offered higher oil yields at low temperatures and reduced residence times.