Potentialities of using liquefied gases as alternative solvents to substitute hexane for the extraction of aromas from fresh and dry natural products

The potential of liquefied gases, n-butane, dimethyl ether, and HFO-1234ze as effective and green alternative solvents to substitute hexane has been evaluated for the extraction of aromatic compounds from dry lavender flowers (Lavandula angustifolia Mill.) and fresh orange peels (Citrus sinensis (L.) Osbeck). The performance of these liquefied gases as solvents has been evaluated in terms of yield, olfactory perception, and composition of the extract and also in terms of energy used, green and economic impacts, and regulatory issues. First, a predictive evaluation of the solvation performance of each solvent was carried out using simulations with the conductor-like screening model for real solvent. Then solid–liquid extractions were performed using liquefied gases at a laboratory scale to determine the extraction yield, the chemical composition, and the olfactory perception of each extract. Finally, the applicability of liquefied gas extractions in an industrial process was assessed, taking into account the potential impact on process, quality, safety, regulation, and environment.     

Recent advances on dual-functional photocatalytic systems for combined removal of hazardous water pollutants and energy generation

Research on Chemical Intermediates - Photocatalytic wastewater treatment and concurrent energy production or metal ions conversion to less harmful products have great potential to address both...     

Oxidation reactions catalysed by molybdenum(VI) complexes grafted on UiO‐66 metal–organic framework as an elegant nanoreactor

A heterogeneous catalyst was synthesized by immobilizing Mo(CO)₃ in a UiO‐66 metal–organic framework. The benzene ring of the organic linker in UiO‐66 was modified via liquid‐phase deposition of molybdenum hexacarbonyl, Mo(CO)₆, as starting precursor to form the (arene)Mo(CO)₃ species inside the framework. The structure of this catalyst was characterized using X‐ray diffraction, and chemical integrity was confirmed using Fourier transform infrared and diffuse reflectance UV–visible spectroscopic methods. The metal content was analysed with inductively coupled plasma. Field emission scanning electron microscopy was used to measure particle size and N₂ adsorption measurements to characterize the specific surface area. This catalytic system was efficiently applied for epoxidation of alkenes and oxidation of sulfides. The Mo‐containing metal–organic framework was reused several times without any appreciable loss of its efficiency.     

Kinetic study of propane dehydrogenation and catalyst deactivation over Pt-Sn/Al2O3 catalyst

The kinetics of propane dehydrogenation and catalyst deactivation over Pt-Sn/Al₂O₃ catalyst were studied. Performance test runs were carried out in a fixed-bed integral reactor. Using a power-law rate expression for the surface reaction kinetics and independent law for deactivation kinetics, the experimental data were analyzed both by integral and a novel differential method of analysis and the results were compared. To avoid fluctuation of time-derivatives of conversion required for differential analysis, the conversion-time data were first fitted with appropriate functions. While the time-zero and rate constant of reaction were largely insensitive to the function employed, the rate constant of deactivation was much more sensitive to the function form. The advantage of the proposed differential method, however, is that the integration of the rate expression is not necessary which otherwise could be complicated or impossible. It was also found that the reaction is not limited by external and internal mass transfer limitations, implying that the employed kinetics could be considered as intrinsic ones.     

Ru(III) complex anchored onto amino-functionalized MIL-101(Cr) framework via post-synthetic modification: an efficient heterogeneous catalyst for ring opening of epoxides

In this work, the metallo Schiff base-functionalized metal–organic framework was prepared by post-synthetic method and used as an electron-deficient catalyst for the alcoholysis of epoxides. In this manner, the aminated MIL-101 was modified with 2-pyridine carboxaldehyde and then the prepared Schiff base reacted with RuCl₃. This new catalyst, MIL-101–NH₂–PC–Ru, was characterized by Fourier transform infrared, UV–Vis spectroscopic techniques, X-ray diffraction, BET, inductively coupled plasma atomic emission spectroscopy and field-emission scanning electron microscopy. In the presence of this heterogeneous catalyst, ring opening of epoxides was performed under mild condition to show the significant ability and successful applications of Lewis acid containing catalysts in corporation with metal–organic frameworks. The reusability of the catalyst was also investigated. No noticeable decrease in the catalytic activity was found after four consecutive times.     

Chemical composition,protoscolicidal effects and acute toxicity of Pistacia atlantica Desf. fruit extract

The present study was designed to evaluate the chemical composition and scolicidal effects of Pistacia atlantica Desf. extract against protoscoleces of hydatid cysts and its acute toxicity in mice model. Various concentrations of the methanolic extract (5–50 mg/mL) were used for 10–60 min. Viability of protoscoleces was confirmed using eosin exclusion test (0.1%). Acute toxicity was also determined in mice model. The main components were β-myrcene (41.4%), α-pinene (32.48%) and limonene (4.66%). Findings demonstrated that P. atlantica extract at the concentrations of 25 and 50 mg/mL after 20 and 10 min of exposure killed 100% protoscoleces. The LD₅₀ of the intraperitoneal injection of the P. atlantica methanolic extract was 2.43 g/kg and the maximum non-fatal dose was 1.66 g/kg. Obtained results showed the potential of P. atlantica extract as a natural source with no significant toxicity for the production of new scolicidal agent to use in hydatid cyst surgery.