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61.
摘要:以过渡金属(Cu, Co)取代磷钨酸为模板剂,硫酸钛为钛源,通过一步模板法合成出一类多酸基PW11M(M=Cu、Co)@TiO2材料,采用FT-IR、XRD、XPS、Raman、SEM和TEM表征手段对材料进行了结构表征. 结果表明,PW11M(M=Cu、Co)被引入到TiO2中,形成了球形核壳结构. N2吸附-脱附测试表明,PW11Co@TiO2具有介孔结构:孔径大小为3.3 nm,比表面积为72.4 m2/g. 在以H2O2为氧化剂,乙腈为溶剂的氧化脱硫反应体系中考察了其催化活性,结果表明:复合材料PW11M(M=Cu、Co)@TiO2表现出良好的催化性能. 其中催化剂PW11Co@TiO2在投入量为40 mg,反应底物为500 ppm,反应温度60 oC,反应40 min后,DBT的脱硫率达到99.7%. 中断和循环实验表明,催化剂PW11Co@TiO2具有良好的稳定性,在相同的反应条件下,循环反应5次后,催化剂的催化活性没有明显下降. 相似文献
62.
Amir Al-HaddadHessa Al-Kendari 《European Polymer Journal》2002,38(2):265-272
The kinetics of liquid crystalline copolyester synthesis via melt transesterification between poly(butylene terephthalate) (PBT), terephthalic acid (TA) and hydroquinone diacetate (HQDA) is examined. Two different copolyester compositions PBT30/(HQDA+TA) 70 and PBT 50/(HQDA+TA) 50 mol% ratio were synthesized. The ratio of HQDA to TA was kept constant for all the reactions.The copolyesters were synthesized via melt polycondensation route at 265°C, 275°C and 285°C using two different transesterification catalysts, zinc acetate and dibutyl tin oxide. A key postulation assumed in this work is that the reaction originates between TA and HQDA to form a dimer which slices PBT chain. The copolyesterification rate constant for a system containing butylene glycol a more nonpolar moiety compared to ethylene glycol in poly(ethylene terephthalate) has been determined. The activation energy values for the different copolymer systems has also been determined. The rate constants for the uncatalyzed and catalyzed copolyesterification reaction and the activation energy values for the reaction have been determined. 相似文献
63.
Well‐defined poly(ethylene oxide)s (PEOs) bearing reactive sites regularly distributed along the chain have been synthesized by the polycondensation of PEO containing a central tertiary amino group with dichloromethane, followed by quaternization with suitable reagents to obtain polyzwitterionic or cationic PEOs with alkyl, allyl, or fluorocarbon pendant groups. The pendant allyl groups have been converted into primary amino groups by reaction with 2‐aminoethanethiol hydrochloride to obtain polyamino‐functionalized PEO.
64.
Yasuyuki Mori Atsushi Sudo Takeshi Endo 《Journal of polymer science. Part A, Polymer chemistry》2019,57(7):792-798
A series of soluble oligo(spiroorthocarbonate)s (OSOCs) were synthesized by polycondensation of tetraethylorthocarbonate with pentaerythritol derivatives. The pentaerythritol derivatives used herein were synthesized from pentaerythritol by attaching substituents on it to improve the solubility of themselves and the resulting OSOCs. The structures of the OSOCs were confirmed by NMR spectroscopy and MALDI‐TOF mass analysis. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 792–798 相似文献
65.
Qingqi Huang Shanshan Zhang Huaguo Yu Huiping Liu Fanhua Xiao Huiying Liao 《Journal of polymer science. Part A, Polymer chemistry》2019,57(10):1097-1104
A series of novel phenolphthalein‐containing sulfonated poly(arylene ether phosphine oxide)s (sPAEPP) with various sulfonation degrees were synthesized by direct polycondensation. The structure of sPAEPP was confirmed by 1H‐NMR, 13C‐NMR, and IR spectroscopy. The high‐molecular weight of these polymers was determined by gel permeation chromatography (GPC). The transparent, tough, and flexible membranes could be achieved by solution casting. The macroscopic properties and microstructure of the obtained membranes were investigated in detail. The results showed that these sPAEPP membranes displayed excellent properties in terms of swelling, proton conductivity, and methanol permeability. For example, sPAEPP‐100 membrane exhibited an appropriate water uptake of 33.1%, a swelling ratio of only 11.7% (lower than 20.1% of Nafion 117), a proton conductivity of 0.11 S cm?1 (similar to that of Nafion 117) at 80 °C, and a methanol permeability of 4.82 × 10?7 cm2 s?1. Meanwhile, it also presented outstanding oxidative stability. Atomic force microscope (AFM) micrographs showed that the hydrophilic domains of the sPAEPP‐100 membrane formed connected and narrow ionic channels, which contributed to its high proton conductivity and good dimensional stability. As a result, sPAEPP‐100 membrane displays excellent application prospect for fuel cells. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 1097–1104 相似文献
66.
脑神经退行性疾病中的有机化学-朊病毒(疯牛病)中的蛋白物理有机化学和自由基化学 总被引:5,自引:0,他引:5
杨池明 《高等学校化学学报》2002,23(2):243-250
通过关于“普里昂”蛋白病毒疾病的已有临床、医学生理、免疫和化学等方面的现象,讨论了朊病毒当中的部分蛋白氧化损伤和蛋白自由基化学本质。 相似文献
67.
Ba—La—O—(F)催化剂和碱性及其OCM反应性能 总被引:2,自引:0,他引:2
采用XRD,TPD和高温原位IR光谱对La2O3,BaO/La2O3,BaF2/La2O3,LaOF和LaOF等催化剂的组成、结构和CO2在催化剂上的吸附状况进行了表征,并结合催化剂性能评价结果对该系列催化剂的碱性及其与OCM反应性能的关系进行了考察。结果表明,催化剂OCM反应性能与其酸碱性的强弱无简单的对应关系. 相似文献
68.
Takatoshi Miyaji Chiaki Azuma Eirou Asaoka Shigeo Nakamura 《Journal of polymer science. Part A, Polymer chemistry》2000,38(7):1064-1072
Wholly aromatic poly(azomethine)s with 1,5‐ or 2,6‐substituted naphthalene moiety in the main chains were prepared in aprotic polar solvents or m‐cresol under various reaction conditions. In the polymerization of 1,5‐diaminonaphthalene with terephthalaldehyde, the polymer that synthesized in (HMPA/DMSO) at room temperature for 24 h by adding 5 wt % of calcium chloride and a very small amount of p‐toluenesulfonic acid showed the highest reduced viscosity in all of the polymers from 1,5‐diaminonaphthalene. The reduced viscosity of poly(azomethine)s synthesized from 2,6‐diaminonaphthalene with 2,6‐diformylnaphthalene in m‐cresol and with terephthalaldehyde in HMPA/DMSO were ηred = 0.35 and 0.36, respectively. The thermal analysis showed the poly(azomethine)s had high thermal stability and the glass‐transition temperatures of these polymers are about 250 °C. The X‐ray diffraction showed that they are partially crystalline. They could be polymerized again by second stage polycondensation in polyphosphoric acid. The reduced viscosities of the obtained polymers were about 2–5 times as high as that of the pristine polymers. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1064–1072, 2000 相似文献
69.
Robert H. Crabtree 《Journal of organometallic chemistry》2004,689(24):4083-4091
The title topic is reviewed with emphasis on catalysis and on recent advances. Alkane σ complexes, Shilov chemistry and oxidative addition routes are covered. Attention is also given to σ bond metathesis, surface-bound organometallics and CH activation involving carbene complexes. Closely related reactions of non-alkane substrates such as the Murai reaction are also discussed. 相似文献
70.
A selective method based on high performance liquid chromatography with electrochemical detection (HPLC-ECD) was developed to enable simultaneous detection of 8-oxo-7,8-dihydroguanine (8-oxoGua) and 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo), products of DNA oxidative damage, in the presence of uric acid (UA), a strong interferent in their electrochemical detection. The method developed consists of HPLC isocratic elution with amperometric detection on a glassy carbon electrode, enabling a detection limit for 8-oxoGua and 8-oxodGuo lower than 1 nM in standard mixtures. Detection of low concentrations up to 25 nM of 8-oxoGua and 8-oxodGuo in the presence of UA in a 104-fold higher concentration was achieved after one-step solid phase extraction (SPE). The method was tested with urine samples and it was possible to detect and quantify the presence of 8-oxoGua, and to confirm that UA was eliminated after uricase degradation and SPE. The LOD found in urine samples was about 80 nM, a value higher than in standard mixtures, due to the increase of background current in the urine matrix. The results presented here contribute to the development of a methodological approach to simultaneous determination of 8-oxoGua and 8-oxodGuo in urine samples. 相似文献