Volume 4, Issue 1

Conventional extraction equipment has many problems like a long mixing time, a large factory area occupation, a large amount of organic solvent consumption and so on. In this paper, a micro solvent extraction system for the extraction of Nd(III) was investigated to solve the above issues. The initial aqueous pH 4.0 and saponification rate 40% of 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (P507) were selected as the optimal experimental conditions. The extraction equilibrium was quickly achieved within 1.5 s, without any mechanical mixing in a narrow channel (100 μm in width and 120 μm in depth) at a volumetric flow rate from 5.55×10 -10 m 3 /s to 1.53×10 -9 m 3 /s. The extraction behavior of Nd(III) in the microreactor is an interface chemical reaction or the diffusion rate of the Nd-complex in the organic phase at low pH and [P507], while the extraction rate is controlled by the rate of metal diffusion in the aqueous phase at high pH and [P507], and the apparent mass transfer rate is up to 3.29×10 -5 mol/m 2 ·s. The extracted complexes are determined by the infrared (IR) spectrum method, and confirm that the extraction is via a cation exchange mechanism in the microreactor.

A simple and facile synthesis of β-amino carbonyl compounds was developed by the one-pot condensation of cyclohexanone, aromatic aldehydes and anilines at 25°C in the presence of silica supported phenylphosphinic acid. β-Amino carbonyl compounds were obtained in moderate to good yields and reasonable diastereoselectivities. This method has the advantages of short reaction time, mild reaction conditions, reusable catalyst, cost efficiency and environment friendly. In addition, acetophenone and aliphatic ketones as reactants were investigated.

In the present work, carbon based heterogeneous acid catalysts have been prepared using various synthesis approaches based on the use of sustainable starting materials. The properties of the catalysts have been investigated using Fourier transformed infra-red (FTIR), scanning electron microscopy (SEM), temperature-programmed desorption (NH 3 -TPD), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The screening studies for catalytic activity in biodiesel production have established that a catalyst prepared by the approach of hydrothermal carbonation followed by sulfonation from the commercial cellulose showed the best catalytic performance and hence was used in a detailed parametric study for the ultrasound assisted (low frequency 20 kHz horn with power of 120 W) synthesis of biodiesel. The study also involved the use of palm fatty acid distillate (PFAD) as the sustainable feedstock. The obtained optimum conditions were a molar ratio of alcohol to oil of 6:1, catalyst concentration of 3 wt%, temperature as 333 K and power dissipation of 120 W with a reaction time of 3 h. Use of different co-solvents (0.2% of PFAD feedstock) was investigated where THF was found to be the best co-solvent. Overall the novelty of the work can be established in terms of the use of sustainable approaches for catalyst synthesis and its subsequent application for biodiesel synthesis based on the use of sustainable feedstock as a PFAD.

Environmentally benign Brønsted acidic ionic liquids with multi-SO 3 H functionality were prepared using N-methyl imidazole and 1,3-propane sultone as the source chemicals. The prepared ionic liquid catalysts were characterized by infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and thermogravimetry (TG) and their catalytic activity in esterification of caprylic acid with methanol was investigated. The results showed that the novel catalyst was very efficient for the reaction, with excellent water and acid resistant ability. Under optimum conditions, the yield of methyl caprylate reached 94.8%. The ionic liquids could be reused six times without a noticeable drop in activity. The kinetic study for the esterification indicated that the reaction order was 1.54 and the activation energy E a was 24.61 kJ/mol.

Iron-doped resorcinol formaldehyde-based aerogels (Fe-RF-AGs) were synthesized and used for the removal of hexavalent chromium [Cr(VI)] from water using adsorption. The synthesis steps of Fe-RF-AGs comprised the gelation by the polycondensation of resorcinol and formaldehyde, followed by drying using supercritical carbon dioxide. The produced mesoporous material was in situ doped with iron (Fe) before the incipience of gel formation, using ferrocene as the metal precursor. Various analytical techniques were used to characterize the prepared materials. The batch adsorption study was performed containing different amounts of Fe in the gel, different initial Cr(VI) concentrations of the solution, and at different solution pH and temperatures. The adsorption rate was found to be first order. The equilibrium data were explained using the Freundlich isotherm. The thermodynamic calculations revealed that the adsorption of Cr(VI) was spontaneous, endothermic and irreversible over the temperature range of 20–40°C. The maximum adsorption capacity of Fe-RF-AGs for Cr(VI) was found to be approximately 55 mg/g at 30°C at the aqueous phase concentration of 275 mg/l, which is larger than most of the data discussed in the literature. The results indicated that Fe-RF-AGs can be used as an effective adsorbent for the removal of Cr(VI) ions from waste water.