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  • 1
    Publication Date: 2018-09-13
    Description: Methyl laurate was synthesized from lauric acid (LA) and methanol via an esterification reaction using ionic liquids (ILs) as catalysts. The efficiencies of three different catalysts, 1-methylimidazole hydrogen sulfate ([Hmim]HSO 4 ), 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSO 4 ) and H 2 SO 4 , were compared. The effect of the methanol/LA molar ratio, reaction temperature, reaction time and catalyst dosage on the esterification rate of LA was investigated by single-factor experiments. Based on the single-factor experiments, the esterification of LA and methanol was optimized using response surface methodology. The results showed that the most effective catalyst was the IL [Hnmp]HSO 4 . The optimal conditions were as follows: [Hnmp]HSO 4 dosage of 5.23%, methanol/LA molar ratio of 7.68 : 1, reaction time of 2.27 h and reaction temperature of 70°C. Under these conditions, the LA conversion of the esterification reached 98.58%. A kinetic study indicated that the esterification was a second-order reaction with an activation energy and a frequency factor of 68.45 kJ mol –1 and 1.9189 x 10 9 min –1 , respectively. The catalytic activity of [Hnmp]HSO 4 remained high after five cycles.
    Keywords: energy, green chemistry
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 2
    Publication Date: 2018-04-19
    Description: A novel non-sequencing approach was developed to detect short DNA fragments ( ca 100 bp) for rapid authentication of two natural products, namely Testudinis Carapax et Plastrum and Trionycis Carapax, based on the difference in mitochondrial genome. Five specifically designed primer reactions were established to target species for reliable identification of their commercial products. They were confirmed to have a high level of inter-species-specificity and good intra-species stability. The limit of detection was estimated to be 1 ng of genomes for all of five assays. Also, the validation results demonstrated that the raw materials and processed products in addition to some of the highly processed products can be conveniently authenticated with good sensitivity and precision by this newly proposed approach. Especially, when reference sample mixtures were assayed, these primer sets have still performed well but not the prevailing COI barcoding technology. These could assist in the discrimination and identification of other animal-derived medicines for their form of raw material, the pulverized and the complex.
    Keywords: biochemistry, biotechnology
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 3
    Publication Date: 2018-08-30
    Description: An improved method was applied for remediating cadmium and copper co-contaminated soil and reducing the metal concentration in Rhizoma chuanxiong . Pot experiments were conducted with six amendments (composed with bentonite, phosphate, humic acid, biochar, sepiolite powder, etc.). The results showed that soil pH, biological activities (soil enzymatic activities and microbial counts) and R. chuanxiong biomass were greatly improved with the addition of amendments in all treatments, especially in T3 and T6. Also, amendments effectively decreased the concentration of malondialdehyde and H 2 O 2 in R. chuanxiong . In the T3 treatment, the bio-available Cd and Cu in soil were significantly decreased by 0.53 and 0.41 mg kg –1 , respectively. Meanwhile, the amendment in T3 reduced Cd and Cu accumulation in R. chuanxiong about 45.83 and 39.37%, respectively, compared to T0. Moreover, the Fourier transform infrared spectroscopy spectra showed the surface functional groups of every amendment. To conclude, this study offers an effective and environmental method to reduce metal accumulation in R. chuanxiong on heavy metal co-contaminated soil.
    Keywords: environmental science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 4
    Publication Date: 2018-10-04
    Description: Forward osmosis (FO) is a concentration process based on the natural phenomena of osmosis. It is considered a breakthrough technology that can be potentially used for concentrating solutions and suspensions. The diluted nature of brine restricts the treatment technologies that can be applied. Then, brine concentration by FO could represent a new emerging technology enabling the application of a wider range of treatment alternatives. The performance of concentrated brine depending upon FO membranes was studied at normal temperature and pressure in this research. Cellulose triacetates on radio-frequency-weldable non-woven support (CTA-NW) and a thin-film composite with embedded polyester screen support (TFC-ES) were compared; and their orientations were considered. The brine was from Chaerhan Salt Lake after extracting potassium as the feed solution, NaCl solution or MgCl 2 solution as the draw solution. The results indicated that CTA-NW exhibited better concentration performance than TFC-ES, while the water fluxes of the two membranes were exactly the opposite. In the case of CTA-NW in active layer facing feed solution orientation with MgCl 2 as the draw solution, the concentration factor of Li + was nearly 3.0. Quantitative structure–activity relationship of FO membranes and concentration characteristics was correlated, based on results of SEM, FTIR and contact angles studies. The concentration performance could be mainly attributed to the porosity and the thickness of FO membranes; while the water flux was dependent on the hydrophily of FO membrane surface.
    Keywords: chemical engineering
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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  • 5
    Publication Date: 2018-08-16
    Description: Seven new cucurbitane glucosides, hemslepensides J-P ( 1 – 7 ), and two known compounds, 16,25- O -diacetyl-cucurbitane F ( 8 ) and 25- O -acetyl-23,24-dihydrocucurbitacin F ( 9 ), were isolated from the tubers of Hemsleya pengxianensis var. jinfushanensis . The structures of 1 – 7 were elucidated using infrared absorption spectroscopy, nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry. The treatment of HT29 cells, human colon cancer cells, with compounds 8 and 9 inhibited cell proliferation. Further study demonstrated that compounds 8 and 9 induced F-actin aggregation, G 2 /M phase cell cycle arrest and cell apoptosis in HT29 cells. In summary, the present study enriched the chemical composition research of H. pengxianensis , and suggested that the compounds 8 / 9 treatment may be a potentially useful therapeutic option for colon cancer.
    Keywords: medicinal chemistry, plant science
    Electronic ISSN: 2054-5703
    Topics: Natural Sciences in General
    Published by Royal Society
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