Solvent Regeneration Methods for Combined Dearomatization, Desulfurization, and Denitrogenation of Fuels Using Deep Eutectic Solvents.

Deep eutectic solvents (DESs) can be used as potential solvents for various applications. However, their recovery depends on both economic and environmental considerations. In this study, the possibilities for the recovery of methyl triphenyl phosphonium bromide/triethylene glycol (MTPPB/TEG 1:4) after the application of combined dearomatization, desulfurization, and denitrogenation of fuels are investigated. The DES was first prepared and characterized for its density, viscosity, and water content. Then, the single-stage liquid-liquid extraction was conducted in addition to testing the repetitive use of the DES. After that, two regeneration methods were studied: the stripping method (with n-heptane) and the washing method (with distilled water or diethyl ether). In addition, a parametric study was conducted to optimize the regeneration methods. The results showed that washing the used DES with distilled water was significantly more effective than stripping the DES with n-heptane. In terms of quinoline reduction, distilled water reduced the quinoline content in the DES from 3.2 to 2.1 wt %, while n-heptane showed a minor reduction in the quinoline content (3.2 to 3 wt %). It was also found that a much more effective recovery could be achieved by (i) increasing the DES-to-regeneration solvent mass ratio and (ii) increasing the number of wash cycles. Furthermore, the regeneration temperature did not have a significant effect on the recyclability of the DES. The results demonstrated that the regenerated DES was as effective in extraction as a fresh batch of DES.

Insights on Chemical Crosslinking Strategies for Proteins.

Crosslinking of proteins has gained immense significance in the fabrication of biomaterials for various health care applications. Various novel chemical-based strategies are being continuously developed for intra-/inter-molecular crosslinking of proteins to create a network/matrix with desired mechanical/functional properties without imparting toxicity to the host system. Many materials that are used in biomedical and food packaging industries are prepared by chemical means of crosslinking the proteins, besides the physical or enzymatic means of crosslinking. Such chemical methods utilize the chemical compounds or crosslinkers available from natural sources or synthetically generated with the ability to form covalent/non-covalent bonds with proteins. Such linkages are possible with chemicals like carbodiimides/epoxides, while photo-induced novel chemical crosslinkers are also available. In this review, we have discussed different protein crosslinking strategies under chemical methods, along with the corresponding crosslinking reactions/conditions, material properties and significant applications.

A new 5-bromoindolehydrazone anchored diiodosalicylaldehyde derivative as efficient fluoro and chromophore for selective and sensitive detection of tryptamine and F- ions: Applications in live cell imaging.

A novel indole hydrazone tagged moiety, 2-((5-bromo-1H-indol-2-yl) methylene) hydrazono) methyl)-4, 6-diiodophenol (BHDL) has been developed for the selective and sensitive detection of biogenic tryptamine and F- ions. The binding dexterity of probe BHDL towards F-/tryptamine (TryptA) has been investigated by UV-visible/fluorescence spectroscopy. In the presence of TryptA, probe exhibits strong enhancement in the emission band at 433 nm and the band at 555 nm underwent a blue shift accompanied by a decrease in intensity by the inhibition of Excited State Intramolecular Proton Transfer (ESIPT) on BHDL. Excitingly, complexation with F- ions as well triggers an enhancement in a fluorescence band at 430 nm with the concomitant disappearance of the emission band at 555 nm due to the inhibition of ESIPT and deprotonation process initiated by the hydrogen bonding complex formation. Further, Density Functional Theoretical (DFT) calculations have been performed to support the mechanism functioned on the probe BHDL in the presence of TryptA/F-.

A facile and efficient synthesis of 1,8-dioxodecahydroacridines derivatives catalyzed by cobalt-alanine metal complex under aqueous ethanol media.

A facile and convenient method for the synthesis of acridines and its derivatives was developed through one-pot, three-component condensation reaction of aromatic aldehydes, 5,5-dimethyl-1,3-cyclohexanedione, aryl amines or ammonium acetates in the presence of a catalytic amount of cobalt-alanine metal complex using aqueous ethanol as a reaction medium is reported. The present described novel methodology offers several advantages over the traditional methods reported in the literature, such as mild reaction conditions, inexpensive catalyst, short reaction times, excellent yields of products, simplicity and easy workup are the advantages of this procedure.

Development and substantiation of a liquid chromatographic method for monitoring organic reactions involved in synthesis of 4-methoxyphenylacetic acid.

A simple and rapid reversed-phase high-performance liquid chromatographic method for monitoring the reactions involved in two different processes for the production of 4-methoxyphenylacetic acid (PMPA) was developed. Impurity profiles of PMPA were used for fingerprinting of the two different synthetic processes by HPLC. Impurities were separated and determined on a Hypersil C18 column with acetonitrile-0.1 M potassium dihydrogen orthophosphate-triethylamine (40:59.95:0.05, v/v) (pH 3.0) as the mobile phase and detection at 280 nm at ambient temperature. The method was substantiated with respect to accuracy, precision, linearity, robustness, limit of detection and quantification. The method was found to be suitable not only for monitoring the reactions but also for quality assurance of PMPA as it could detect impurities at the level of 4 x 10(-9) g.