Carboxymethyl
cellulose (CMC), microcrystalline cellulose (MCC),
and xylan are cross-linked with β-cyclodextrin (βCD) using
ethylene glycol diglycidyl ether cross-linker to produce hydrogels,
namely, βCD-CMC, βCD-MCC, and βCD-xylan, in alkaline
medium at 1:1 mole ratio. Additionally pure βCD gel is also
prepared in alkaline medium. The synthesized hydrogels are characterized
by Fourier transform infrared spectroscopy, and the swelling ratio,
gel fraction, and the morphologies are observed by a microscope. The
hydrogels are used to adsorb cadmium (Cd(II)) and nickel (Ni(II))
ions from aqueous solution. The adsorption studies are carried out
by varying adsorbent dosage from 80 to 500 mg, concentration from
5 to 500 mg L–1, pH from 2 to 8, and temperature
from 25 to 55 °C. The equilibrium adsorption data closely follow
the Langmuir model, suggesting the monolayer adsorption of metal ions
by the hydrogels. The adsorption kinetics are found to closely follow
the pseudo-second-order model.
Rapid discovery of a deep eutectic solvent (DES) and its increasing application in various scientific applications demands a well-defined polarity scale for the new generation of eutectic solvents. The tunable nature of a DES facilitates to increase its number by combining various hydrogen bond acceptors and donors in multiple molar ratios. Therefore, the experimental measurement of polarity scale represented by solvatochromic parameters is a cumbersome task. In this context, we have developed a first-principle-based conductor-like screening model-real solvent (COSMO-RS)-derived predictive modeling approach to predict the Kamlet−Taft solvatochromic parameters of 26 hydrophilic and 62 hydrophobic DESs. The COSMO-RS-derived energies, that is, hydrogen bonding energy (E HB ), misfit energy (E MF ), and van der Waals energy (E VDW ), are linearly correlated with the experimental data set of 28 DESs having 4 choline chloride, 17 tetraalkylammonium organic salt, 4 menthol, and 3 betaine subclasses. A lowest root-mean-square deviation (rmsd) of 0.06% for the choline chloride class of DESs and a highest rmsd of 3.14% for the tetrabutylammonium chloride class of DESs are obtained. Therefore, the correlated models are then extended to develop 60 DESs consisting of 15 choline chloride DESs, 4 different hydrophilic DESs, 17 tetraalkylammonium organic salt origin DESs, 7 menthol DESs, and 17 thymol-based DESs.
The current work reports the judicial selection and subsequent dehydrogenation reaction with ionic liquid (IL) facilitated ethylene diamine bisborane (EDAB). Quantum chemical based COSMO-SAC (COnductor like Screening MOdel Segment Activity Coefficient) model was initially used to screen the ILs as available from Sigma Aldrich. LUMO-HOMO calculation was then performed to analyze the stability of EDAB/IL complexes. The molecular modeling studies converged on the two ILs, namely 1-ethyl-3-methyl imidazolium acetate ([EMIM][OAc]) and 1-butyl-3-methyl imidazolium acetate ([BMIM][OAc]), which were subsequently chosen for the dehydrogenation experiments. The thermal dehydrogenation of EDAB was carried out at 95 C and 105 C under vacuum so as to prevent generation of oxygen moieties. A total of 3.96 and 3.52 equivalents of hydrogen were released from the desorption of EDAB/[BMIM][OAc] and EDAB/[EMIM][OAc], respectively, at 105 C. The purity of released gas was confirmed by gas chromatographic analysis, while the catalytic activity of ILs was confirmed by 1 H NMR characterization of pure EDAB, ILs and EDAB/IL complexes both before and after the reaction. 11 B NMR analysis confirms the presence of trigonal boron (sp 2 ) BH 2 group as the only hydrogen containing boron moiety in dehydrogenated EDAB. Further, the two-stage release mechanism of EDAB was also verified by thermogravimetric analysis. High resolution mass spectrometry was able to detect the mass of cyclic repeat units in the polymeric chain containing an sp 2 BH 2 group. † Electronic supplementary information (ESI) available: The COSMO-SAC parameters and the sigma proles of EDAB, imidazolium cations and acetate anions. Further it also depicts the HOMO-LUMO energy gap of EDAB, [EMIM] [OAc] and [BMIM][OAc]. SeeFig. 8 Plot for 11 B NMR. (a) EDAB/[BMIM][OAc] before reaction, (b) EDAB/[BMIM][OAc] after reaction.This journal is
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.