نتایج جستجو برای: solvent assisted
تعداد نتایج: 184120 فیلتر نتایج به سال:
Pomegranate seed oil was extracted in a closed-vessel high-pressure microwave system. The characteristics of the obtained oil, such as fatty acid composition, free fatty acidity, total phenolic content, antioxidant activity and colour, were compared to those of the oil obtained by cold solvent extraction. Response surface methodology was applied to optimise extraction conditions: power (176-300...
Cocrystallization between analyte and matrix is required by matrix-assisted laser desorption/ionization and can represent a significant limitation of the technique. A molecular beam expansion, mass spectrometric method has been developed to explore the possibility of using pure solvents as matrix to avoid cocrystallization. Two kinds of solvent, liquid CS2 and liquid or supercritical CO2, have ...
With the strategic goal of “carbon peaking and carbon neutral” in China, new requirements are also put forward for thermal recovery heavy oil. In view problems excessive greenhouse gas emission, low steam utilization rate, poor economic efficiency, limited reservoir application stimulation replacement technology emerging technologies medium- low-temperature fluid, solvent-assisted high-temperat...
An alternative method for the extraction of polychlorinated biphenyls (PCBs) in ash samples, which is less time and solvent consuming than Soxhlet extraction, is presented. A study was carried out to evaluate the possibilities of microwave-assisted extraction (MAE) to determine exactly which parameters affect the efficiency of the process, since direct extrapolation of extraction conditions for...
Lipids were extracted from Isochrysis galbana using a microwave-assisted method accompanied by various types of organic solvents. The effects of organic solvent type and microwave input energy on the fatty acid characteristics of the extracted lipids and their biodiesel product were investigated. Variations in the characteristics of the lipids extracted using a combination of n-hexane and iso-p...
background & aim: essential oils are isolated from different sections of plants such as flowers, seeds, leaves, stems and roots. essential oils are applied extensively in producing of perfumes, cosmetics, foods, beverages and confectioneries and as ingredients of disinfectants and insecticides. experimental: essential oil are obtained by several isolation methods, such as hydrodistillation ...
A family of α-aryl-α-aminophosphonates and α-aryl-α-aminophosphine oxides was synthesized by the microwave-assisted solvent-free addition of dialkyl phosphites and diphenylphosphine oxide, respectively, to imines formed from benzaldehyde derivatives and primary amines. After optimization, the reactivity was mapped, and the fine mechanism was evaluated by DFT calculations. Two α-aminophosphonate...
Single-nitrogen containing saturated cyclic amines are an important part of both natural and synthetic bioactive compounds. A number of methodologies have been developed for the synthesis of aziridines, azetidines, pyrrolidines, piperidines, azepanes and azocanes. This review highlights some facile and green synthetic routes for the synthesis of unsubstituted, multisubstituted and highly functi...
A practical method was elaborated for the synthesis of (aminomethylene)bisphosphine oxides comprising the catalyst- and solvent-free microwave-assisted three-component condensation of primary amines, triethyl orthoformate and two equivalents of diphenylphosphine oxide. The method is also suitable for the preparation of (aminomethylene)bisphosphonates using (MeO)2P(O)H/(MeO)3CH or (EtO)2P(O)H/(E...
An NMR analytical protocol is proposed to characterize saffron samples of different geographical origin (Greece, Spain, Hungary, Turkey and Italy). A microwave-assisted extraction procedure was developed to obtain a comparable recovery of metabolites with respect to the ISO specifications, reducing the solvent volume and the extraction time needed. Metabolite profiles of geographically differen...
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