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  • Author or Editor: J. Duan x
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Abstract  

A novel method that spent nuclear fuel is converted into nitrates with N2O4, and then nitrates are extracted with TBP in supercritical CO2 (SC-CO2), has been developed for reprocessing of spent nuclear fuel, which has a potential prospect because of its potential to decrease generation of the secondary liquid waste. In this paper, conversion of Nd2O3 with N2O4 into its nitrate under various conditions and extraction of the conversion product with TBP in SC-CO2 were investigated. When temperature was 60–120 °C, the molar ratio of H2O to Nd2O3 was from 1 to 6, and molar ratio of N2O4 to Nd2O3 was above 8, complete conversion of Nd2O3 into its nitrate was achieved. The conversion product was characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR) and Raman spectroscopy. Quantitative extraction of the conversion product with TBP in supercritical CO2 was also achieved under experimental conditions.

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Summary

A preparative high-speed countercurrent chromatograph (HSCCC) method for the isolation and purification of C6-C2 natural alcohol and benzyl ethanol from Forsythia suspensa was successfully established. Cornoside, forsythenside F, forsythiaside, and acteoside were rapidly obtained for the first time by HSCCC with a two-phase solvent system ethyl acetate-n-butanol-methanol-water (5:1:0.5:5, υ/υ) in one-step separation. The purities of them were all above 97% as determined by high-performance liquid chromatography, and the combination of ESI-MS and NMR analysis confirmed the chemical structures of the four compounds.

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Abstract  

New complexes of the non-natural amino acid (p-iodo-phenylalanine) with divalent cobalt and nickel ions have been synthesized. The composition of the complexes is [M(IC6H4CH2CHNH2COO)2]2.5H2O (M=Co, Ni) and the crystal structure belongs to orthorhombic system. Infrared spectra indicate the nature of bonding in the complex. The first stage in the thermal decomposition process of the complex shows the presence of crystal water. The thermal decomposition process of cobalt complex differs from that of nickel. The intermediate and final residues in the thermal decomposition process have been analyzed to check the pyrolysis reactions. Thermal analysis indicates that the iodine atom of the ligand may coordinate to the metal ion in the lattice.

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Abstract  

The thermal decomposition of strontium acetate hemihydrate has been studied by TG-DTA/DSC and TG coupled with Fourier transform infrared spectroscopy (FTIR) under non-isothermal conditions in nitrogen gas from ambient temperature to 600°C. The TG-DTA/DSC experiments indicate the decomposition goes mainly through two steps: the dehydration and the subsequent decomposition of anhydrous strontium acetate into strontium carbonate. TG-FTIR analysis of the evolved products from the non-oxidative thermal degradation indicates mainly the release of water, acetone and carbon dioxide. The model-free isoconversional methods are employed to calculate the E a of both steps at different conversion α from 0.1 to 0.9 with increment of 0.05. The relative constant apparent E a values during dehydration (0.5<α<0.9) of strontium acetate hemihydrate and decomposition of anhydrous strontium acetate (0.5<α<0.9) suggest that the simplex reactions involved in the corresponding thermal events. The most probable kinetic models during dehydration and decomposition have been estimated by means of the master plots method.

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Summary

An efficient and robust method for analyzing constituents of a well-known traditional Chinese medicine (TCM) formula SiWu decoction (SWD) contains Angelicae Sinensis Radix (ASR), Chuanxiong Rhizoma (CR), Paeoniae Radix Alba (PRA), and Rehmanniae Radix Praeparata (RRP) by ultra high-performance liquid chromatography (UHPLC)/time-of-flight mass spectrometry (TOF-MS) was established. The method efficiently applied to the separation of 75 compounds, including organic acids, phthalides, phenylpropanoid glycosides, iridoid glycosides, monoterpene glycosides, and galloyl glycosides in the complex prescription, 52 compounds in this study can be unambiguously identified or tentatively characterized. The separation was achieved within 20 min at the optimized chromatographic conditions. Our study provided a reliable and high-efficient method for the understanding of the chemical basis of SWD.

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A method was developed for the preparative separation of two alkaloids from the crude extract of the radix of Rauvolfia verticillata (Lour.) Baill. in a single run. The two-phase solvent system composed of petroleum ether–ethyl acetate–methanol–water (5:5:2:8, v/v), where triethylamine (40 mmol/L) was added to the upper organic phase as the stationary phase and hydrochloric acid (10 mmol/L) was added to the lower aqueous phase as the mobile phase, was selected for this separation by pH-zone-refining counter-current chromatography (PZRCCC). For the preparative separation, the apparatus was rotated at a speed 850 rpm, while the mobile phase was pumped into the column at 2 mL/min. As a result, 112 mg of reserpine and 21 mg of yohimbine were obtained from 3 g of crude extract in a single run. The analysis of the isolated compounds was determined by high-performance liquid chromatography (HPLC) at 230 nm with purities of over 91.0%, and the chemical identification was carried out by the data of electrospray ionization–mass spectrometry (ESI–MS) and nuclear magnetic resonance (NMR) spectroscopy. The technique introduced in this paper is an efficient method for preparative separation of reserpine and yohimbine from devil pepper radix. It will be beneficial to utilize medicinal materials and also useful for the separation, purification, and pharmacological study of Chinese herbal ingredients.

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