Recent advances in biodiesel production: Challenges and solutions

Post-Synthesis modification of metal-organic frameworks using Schiff base complexes for various catalytic applications



The supported ionic liquids have shown immense potential for numerous applications
in catalysis and separation science. In the present review, the remarkable contribution
of supported ionic liquids has been highlighted. The main emphasis has been laid on
describing the facile separation of gas from binary gas mixtures owing to the capability of
selective transport of permeable gases across supported membranes and removal of environmentally
hazard sulfur compounds from fuels. The catalytic action of supported ionic
liquids has been discussed in other applications such as biodiesel (biofuel) synthesis by
transesterification/esterification processes, waste CO2 fixation into advantageous cyclic
carbonates, and various chemical transformations in organic green synthesis. This review
enclosed a maximum of the published data of the last ten years and also recently accomplished
work concerning applications in various research areas like separation sciences, chemical transformations
in organic green synthesis, biofuel synthesis, waste CO2 fixation, and purification of fuels by desulfurization.


Recent Advances in Applications of Supported Ionic Liquids

Magnetized ZIF-8 impregnated with sodium hydroxide as a heterogeneous catalyst for high-quality biodiesel production

This article focused on the construction and characteristics of novelty and sensitivity of modified carbon paste electrodes for determination of doxycycline hydrochloride (DC.HCl) in urine, serum and pharmaceutical preparations. It was based on the incorporation of α-cyclodextrine (α-CD) and multi-walled carbon nanotube (MWCNT) ionophores which improved the characteristics of the electrodes with tricresylphosphate (TCP) (electrode I) and o-nitrophenyloctylether (o-NPOE) (electrode II) as plasticizers, respectively. The constructed electrodes, at optimum paste composition, exhibited good Nernstian response for determination of doxycycline hydrochloride over a linear concentration range from 1.0 × 10–7 to 1.0 × 10–2 and 1.22 × 10–7 to 1.0 × 10–2 mol L–1 with detection limit of 1.0 × 10–7 and 1.22 ×10–7 mol L–1 and with slope values of (58.7 ± 0.2) mV decade–1 and (58.0 ± 0.6) mV decade–1, for modified carbon paste electrodes (MCPEs; electrodes I and II), respectively. The results showed fast dynamic response time (about 6–7 s) and long lifetime in the range from 4 to 5 months where the response of the electrodes was not affected by pH variation within the range from 2 to 8 and 2 to 7.5 for electrodes I and II, respectively. Electrodes I and II showed high selectivity for doxycycline hydrochloride with respect to a large number of interfering species including foreign inorganic, organic species, excipients and the fillers added to the pharmaceutical preparation. The constructed electrodes were successfully applied for determination of DC.HCl in pure form, its pharmaceutical preparations and biological fluids (urine and serum) using standard addition, calibration curves and potentiometric titration methods. The results obtained using these potentiometric electrodes were comparable with those obtained using official method. The results were satisfactory with excellent percentage recovery comparable or better than those obtained by other routine methods.

Ferial A. Zaher

Papers

Biodiesel production by direct esterification of fatty acids with propyl and butyl alcohols