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91.
92.
Xue Zhou Jie Wang Lifang Sun Anya Xiang Qinglong Shi Haichi Li Dan Zhou Fahuan Ge 《Journal of separation science》2020,43(13):2646-2656
A green and efficient strategy was established and optimized for target‐oriented extraction, enrichment and separation of cadinene sesquiterpenoids from Eupatorium adenophorum Spreng., using the combination of supercritical fluid extraction, molecular distillation, and industrial preparative chromatography for the first time. The extraction conditions of supercritical fluid extraction were initially optimized by orthogonal experimental design. Under the optimum conditions, the contents of 9‐oxo‐10,11‐dehydroageraphorone and 10Hβ‐9‐oxo‐ageraphorone, which were 55.00% and 6.01%, respectively, were much higher than conventional extraction methods. Then, the molecular distillation enrichment method was established and investigated by response surface methodology technology, which showed strong specificity for enriching target compounds and removing impurities from crude extracts. Under the optimum conditions of molecular distillation, total contents of cadinene sesquiterpenoids were increased to 89.19%. Finally, a total of 146 mg of 9‐oxo‐10,11‐dehydroageraphorone and 29 mg of 10Hβ‐9‐oxo‐ageraphorone were easily obtained by industrial preparative chromatography, from 200 mg of distillation fraction, with purities over 99%. The contents of target components were analyzed by HPLC, and structures of them were identified by high‐resolution MS, 1H‐NMR, and 13C‐NMR spectroscopy. These results indicate that it is a simple, effective, and eco‐friendly strategy, which is easily converted into industrial scale. 相似文献
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Abstract Novel bone-targeting prodrugs containing dendritic naproxen and poly(aspartic acid) oligopeptide were synthesized in a convergent approach and were characterized by NMR, mass spectral, and elemental analysis techniques. The modified naproxen prodrugs showed a high affinity to hydroxyapatite in vitro and provided an effective entry for the synthesis of a dendritic naproxen–poly(aspartic acid) oligopeptide conjugates used for bone targeting. 相似文献
95.
The effects of a room temperature ionic liquid, 1-butyl-3-methylimidazolium terafluoroborate ([Bmim]BF4), on the photocatalytic performance of Degussa P25 TiO2 were investigated. Also, the photocatalysis mechanism was systematically analyzed by conducting different reactive radical trapping experiments. The results showed that photogenerated electrons were the main reactive species involved in the photocatalytic degradation of methyl orange (MO), while ?OH radicals and photogenerated holes played an important role in the photocatalytic decomposition of rhodamine B (RhB). The addition of ionic liquid (IL) could slightly enhance the photocatalytic degradation rate of MO because adsorption of [Bmim]+ ions on the TiO2 surface not only enhanced traping and transfer of photogenerated electrons, but also facilitated adsorption of negatively charged MO. On the contrary, IL suppressed the degradation rate of RhB because [Bmim]+ on the TiO2 surface not only hindered the access of positively charged RhB to TiO2, but also restricted the diffusion of positively charged holes to the TiO2/solution interface. 相似文献
96.
Ting Jin Peng‐Fei Wang Qin‐Chao Wang Kunjie Zhu Tao Deng Jiaxun Zhang Wei Zhang Xiao‐Qing Yang Lifang Jiao Chunsheng Wang 《Angewandte Chemie (International ed. in English)》2020,59(34):14511-14516
P2‐type layered oxides suffer from an ordered Na+/vacancy arrangement and P2→O2/OP4 phase transitions, leading them to exhibit multiple voltage plateaus upon Na+ extraction/insertion. The deficient sodium in the P2‐type cathode easily induces the bad structural stability at deep desodiation states and limited reversible capacity during Na+ de/insertion. These drawbacks cause poor rate capability and fast capacity decay in most P2‐type layered oxides. To address these challenges, a novel high sodium content (0.85) and plateau‐free P2‐type cathode‐Na0.85Li0.12Ni0.22Mn0.66O2 (P2‐NLNMO) was developed. The complete solid‐solution reaction over a wide voltage range ensures both fast Na+ mobility (10?11 to 10?10 cm2 s?1) and small volume variation (1.7 %). The high sodium content P2‐NLNMO exhibits a higher reversible capacity of 123.4 mA h g?1, superior rate capability of 79.3 mA h g?1 at 20 C, and 85.4 % capacity retention after 500 cycles at 5 C. The sufficient Na and complete solid‐solution reaction are critical to realizing high‐performance P2‐type cathodes for sodium‐ion batteries. 相似文献
97.
Synthesis of Triple‐Layered Ag@Co@Ni Core–Shell Nanoparticles for the Catalytic Dehydrogenation of Ammonia Borane 下载免费PDF全文
Dr. Fangyuan Qiu Dr. Guang Liu Dr. Li Li Dr. Ying Wang Changchang Xu Dr. Cuihua An Chengcheng Chen Dr. Yanan Xu Yanan Huang Prof. Yijing Wang Prof. Lifang Jiao Prof. Huatang Yuan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):505-509
Triple‐layered Ag@Co@Ni core–shell nanoparticles (NPs) containing a silver core, a cobalt inner shell, and a nickel outer shell were formed by an in situ chemical reduction method. The thickness of the double shells varied with different cobalt and nickel contents. Ag0.04@Co0.48@Ni0.48 showed the most distinct core–shell structure. Compared with its bimetallic core–shell counterparts, this catalyst showed higher catalytic activity for the hydrolysis of NH3BH3 (AB). The synergetic interaction between Co and Ni in Ag0.04@Co0.48@Ni0.48 NPs may play a critical role in the enhanced catalytic activity. Furthermore, cobalt–nickel double shells surrounding the silver core in the special triple‐layered core–shell structure provided increasing amounts of active sites on the surface to facilitate the catalytic reaction. These promising catalysts may lead to applications for AB in the field of fuel cells. 相似文献
98.
The effects of Na Al H4, Ti F3 and Na Al H4-Ti F3co-additive on dehydriding reaction of Mg(Al H4)2are systematically investigated. The onset dehydrogenation temperature of the co-doped Mg(Al H4)2composites decreased to 74°C, which is about 59°C lower than that of pure Mg(Al H4)2. The dehydrogenation kinetics of Na Al H4-Ti F3co-doped Mg(Al H4)2sample was also improved, which released about 94%hydrogen within 48 min, but no visible hydrogen was released from pure Mg(Al H4)2under the same conditions. The activation energy of co-doped Mg(Al H4)2was 85.6 k J mol-1, which was significantly lower than that of additive-free Mg(Al H4)2sample. The synergetic effects of Na Al H4 and Ti F3 on the dehydrogenation performance of Mg(Al H4)2were confirmed. In addition, a possible catalytic mechanism is discussed, regarding the different roles of Na Al H4 and Ti F3 on Mg(Al H4)2. 相似文献
99.
100.
Properties of composition operators induced by analytic self-maps on the unit disk of the complex plane in Hardy-Orlicz spaces are discussed. Results are concerned about boundedness, invertibility, compactness, Fredholm operators and spectra of composition operators. 相似文献