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31.
《Analytical letters》2012,45(2):339-351
Abstract A stable poly(crystal-violet) (PCV) electroactive film was electrodeposited on a glassy carbon electrode (GCE). The redoxation of hydroquinone showed a pair of well-defined peaks on a PCV electrode with a potential difference of 30 mV, which is 120 mV less than that obtained on the GCE. At optimal conditions, the PCV electrode linearly responded to the hydroquinone in the range of 4 × 10?6 mol · L?1 to 3.2 × 10?3 mol · L?1 and a detection limit of 8 × 10?8 mol · L?1 was obtained. The separations of the oxidation peak potentials between hydroquinone and the coexisting o-hydroquinone and m-hydroquinonewere 100 mV and 430 mV, respectively, which allows their simultaneous determination. The detection of hydroquinone in artificial sewage water was demonstrated with satisfactory results. 相似文献
32.
阻抑动力学光度法测定痕量对苯二酚 总被引:13,自引:0,他引:13
基于在硫酸和聚乙烯醇溶液中,对苯二酚能抑制Fe(Ⅲ)催化中性红与H2O2之间的褪色反应,建立了一种测定痕量对苯二酚的新方法,同时研究了该方法的动力学条件。该方法的测定范围为0.20~6.0mg/L;检出限为2.3×10-4g/L;ε535=1.2×104L·moL-1·cm-1。用于废水中对苯二酚的测定,结果满意。 相似文献
33.
Plectranthus (Lamiaceae), which—according to the latest systematic revision—includes three separate genera (Coleus, Plectranthus sensu stricto, and Equilabium), is a genus widely used in traditional medicine—mainly in the treatment of various ailments of the digestive tract, respiratory tract, and skin. Many species of Plectranthus s.l. have been shown to produce phenolic compounds and terpenes. Diterpenes, especially those of the abietane class, are the most studied group of secondary metabolites found in Plectranthus s.l., which is characterized by a significant structural diversity arising from the oxygenation and further rearrangement of the basic tricyclic abietane skeleton to a complete aromatization of the ring system. This review summarizes the known information on abietane diterpenes, showing their structures, sources, and biosynthesis. A classification of these compounds into nine groups, according to the arrangement of their ring C, is used. Royleanones, spirocoleons, and hydroquinones are the largest classes of abietane diterpenes, covering more than 70% of all the compounds reviewed. 相似文献
34.
35.
LI Hua-Ming YE Xing-Kai YANG Xiang-Guang WU Yue Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun Jilin S China 《中国化学》1997,15(6):512-527
The catalytic oxidation of cyclohexene to cyclohexanone using Pd(OAc)2/HQ/FePc was investigated in an acidic aqueous solution of acetonitrile. The role of each component of this system in the oxidation of cyclohexene was explored by means of UV-VIS, IR, XPS spectroscopy and cyclic voltammetry, respectively. Based on the experimental results, the mechanism of the oxidation of cyelohexene catalyzed by Pd(OAc)2/HQ/FePc was elucidated. 相似文献
36.
O. T. Kasaikina Z. S. Kartasheva A. B. Mazaletskii N. Yu. Sakova Zh. V. Shmyreva Kh. S. Shikaliev 《Russian Chemical Bulletin》1992,41(2):329-332
Phenols (hydroquinone and -tocopherol) and heterocyclic aminophenols (2,2,4-trimethyl-6-ethoxy-1,2-dihyroquinoline) reduce N,N-diphenyl-p-quinonediimine (A) to the diamine. With difunctional hydrogen atom donors, the reaction rate is proportional to the concentrations of the reactants. The effective rate constants have been determined over a range of temperatures. In the reaction of A with -tocopherol, plots of rate versus initial concentrations are nonlinear, 2,6-Di-tert-butyl-4-methylphenol and 2,2,4-trimethyl-6-ethoxy-1,2-dihyroquinoline do not react with A under the same conditions.N.N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 117977 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 417–420, February, 1992. 相似文献
37.
聚醚醚酮(PEEK)自工业化以来[1],由于其优异的性能已在机械、航天等领域得到广泛应用.各种聚芳醚酮类聚合物相继被开发出来.但以亲电缩聚路线制备聚醚醚酮醚酮(PEEKEK)的报道较少[2].本文以二苯醚和4-氟苯甲酰氯为主要反应试剂,采取付氏酰基化... 相似文献
38.
Fumio Toda Koichi Tanaka Thomas C. W. Mak 《Journal of inclusion phenomena and macrocyclic chemistry》1985,3(3):225-233
The title compounds crystallize in space groupC2/c withZ=4; C18H12O2Cl2·HO(CH2)4OH,a=16.186(3),b=7.626(1),c=16.939(3) Å, =91.32(2)°,R
F
=0.048 for 1743 observed MoK reflections; C26H20O2·HO(CH2)4OH,a=11.881(3),b=13.009(4),c=16.689(4) Å, =110.67(2)°,R
F
=0.066 for 1783 data points. Both structures feature centrosymmetric hydrogen-bonded (OH)4 rings formed by molecular components located in special positions. Different packing modes account for the observed conformations (g
+
ag
– andaaa, respectively) of 1,4-butanediol and its possible replacement by 1,2-ethanediol as a guest in the former crystal structure.
Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82009 (25 pages).Dedicated to Professor H. M. Powell. 相似文献
39.
设计、合成了两种蝶形主体分子:2,5-二(三苯甲基)对苯二酚1,2,5-二(二苯甲基)对苯二酚2.1和2可与许多有机小分子形成配位包合物。用IR表征了主体分子1和2 的包结物, 用1H NMR测定了主客体分子的摩尔比:1•DMF (1:2),1•DMSO (1:2),1 •吡啶 (1:2),1•环戊酮 (2:3)和2•DMF 1:2),2•DMSO (1:2),2 •THF (1:1),2•苯甲醛(1:2),2•苯乙酮 (1:2),2•2,5-己二酮
(1:1),2 •N-甲基-2-吡咯烷酮 (1:3)。单晶X-射线衍射分析了包结物2·苯甲醛的晶体结构,在分子间氢键的相互作用下晶体得以稳定。 相似文献
40.