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81.
Summary The separation and quantitative determination of diphenylamine and its mono-derivatives in single-base gun propellants during
aging was investigated by High Performance Liquid Chromatography (HPLC). We have defined optimal conditions to allow determination
of diphenylamine and its mono-derivatives during aging until their levels fell below limits of detection.
These compounds were determined in a single-base gun propellant during a storage period of 168 hours at 100°C using a developed,
successfully verified HPLC method. 相似文献
82.
Veličković Jelena Đ. Andrić Deana Roglić Goran Tešic Živoslav Lj. Milojković-Opsenica Dušanka M. 《平面色谱法杂志一现代薄层色谱法》2004,17(4):255-260
JPC – Journal of Planar Chromatography – Modern TLC - The chromatographic behavior of fourteen 1-arylpiperazine derivatives has been studied by thin-layer chromatography on both silica... 相似文献
83.
N. Pejić J. Maksimović D. Ribič Lj. Kolar-Anić 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(9):1490-1495
Dynamic behavior of hydrogen peroxide decomposition catalyzed by iodate and hydrogen ions (the Bray-Liebhafsky reaction),
in a continuous stirred tank reactor is investigated. The experimental results are obtained at one operational point in concentration
phase space by varying mixed inflow concentrations of the sulfuric acid. The experimental evidences for the onset and termination
of oscillatory behavior via the saddle node infinite period bifurcation as well as some kind of the Andronov-Hopf bifurcation are presented. In addition,
the possibility of excitability of a stable steady state by thiamine was observed.
The article is published in the original. 相似文献
84.
The composite polymer layers consisting of polyaniline (PANI) and poly(o-phenylenediamine) (poly(o-PDA)) were electrodeposited on a platinum electrode by simultaneous electrochemical oxidation of corresponding monomers from aquaeous hydrochloric solutions. The growth of PANI and poly(o-PDA) occurs separately resulting in layers with two distinct, finely distributed phases. The first deposited layers are composed mainly of poly(o-PDA) and become richer in PANI as the electropolymerization proceeds. The aniline/o-PDA copolymer was not formed during electrodeposition, as evidenced by cyclic voltammetry and Fourier-transformed IR spectroscopy. It was demonstrated that the electrochromic properties of resulting composite layers are the combination of yellow/brown-reddish and green/dark blue observable color transitions which are characteristics of poly(o-PDA) and PANI, respectively. Electrocatalytic properties of the electrosynthesized composite layers were investigated on quinone/hydroquinone (Q/H2Q) redox system and it was shown that the composite layers increase the heterogeneous electron transfer rate with a magnitudes ranging from those obtained on pure poly(o-PDA) to those obtained on pure PANI layer. 相似文献
85.
86.
Branka Dra?i? Sanja Grguri?-?ipka Ivanka Ivanovi? ?ivoslav Lj. Te?i? Gordana Popovi? 《Journal of the Iranian Chemical Society》2012,9(1):7-12
Acid?Cbase equilibria of the aqua adducts of Ru(II) arene complexes, general formulae [(??6-p-cymene)Ru (L1?3)Cl2] where L1?=?3-acetylpyridine (1), L2?=?4-acetylpyridine (2) and L3?=?2-amino-5-chloropyridine (3), then [(??6-p-cymene)Ru(HL4)Cl2] with HL4?=?isonicotinic acid (4); [(??6-p-cymene)Ru(HL5?8)Cl] where H2L5?=?2,3-pyridine dicarboxylic acid (5), H2L6?=?2,4-pyridine dicarboxylic acid (6), H2L7?=?2,5-pyridine dicarboxylic acid (7) and H2L8?=?2,6-pyridine dicarboxylic acid (8) have been studied. pK a values were determined by potentiometry at 25?°C and constant ionic strength of 0.1?M NaNO3. The assumed equilibria were confirmed by UV and 1H-NMR spectroscopy. 相似文献
87.
M. S. Jovanović J. Brborić S. Vladimirov Lj. Šuturkova 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(3):555-560
The partition coefficient (log P) for n-octanol/water system was calculated applying PACO program for various theoretically possible mono and dihalogenated IDA derivatives. Some of the synthesized ligands (SOLCOIODIDA, IODIDA and DIIODIDA) were labeled with the technetium-99m. The biodistribution and influence of bilirubin on their biokinetics were investigated in rats. The correlation between partition coefficients of ligands increase (log P) and better hepatobiliary properties of 99mTc-IDA derivatives was determined. The values of log P increase from 1.16 for SOLCOIODIDA, 3.11 for IODIDA to 3.47 for DIIODIDA. In correlation with these results, biliary excretion decreased for 59% for 99mTc-SOLCOIODIDA and 11% for 99mTc-IODIDA and 99mTc-DIIODIDA under hyperbilirubinemia (3.5 min after injection) and 45%, 11% and 0.38% respectively (15 min after injection). The highest biliary excretion had 99mTc-DIIODIDA (55.4% for 3.5 min). Considering the correlation between hepatobiliary properties and log P, the evaluation of biological properties for various trifluoromethyl mono and dihalogenated IDA derivatives was performed on the basis of the calculated log P in order to synthetize a new radiopharmaceutical for hepatobiliary scintigraphy. 相似文献
88.
Both compounds were prepared via a common intermediate. The key features included the direct synthesis of the indan skeleton and the radical addition to a quinone. 相似文献
89.
Tomáš Hartman Vladimír Herzig Miloš Buděšínský Jindřich Jindřich Radek Cibulka Tomáš Kraus 《Tetrahedron: Asymmetry》2012,23(22-23):1571-1583
A series of flavin–cyclodextrin conjugates has been prepared and tested in the enantioselective oxidations of prochiral aromatic and aliphatic sulfides with hydrogen peroxide. The newly prepared conjugates contain isoalloxazinium or alloxazinium moieties attached to the primary rim of α- and β-cyclodextrins at the C-6 positions. In addition, flavinium units were attached to the secondary rim of the β-cyclodextrin macrocycle. The relationship between the structural features and the catalytic performance of the conjugates, including those recently reported by us, was analyzed. The rate and enantioselectivity of the sulfoxidations catalyzed by flavin–cyclodextrin conjugates are influenced mainly by the size of the cyclodextrin cavity, the type of flavin unit (alloxazine or isoalloxazine), and by the relative orientation of the flavin and cyclodextrin moieties. 相似文献
90.
A model system for the synthesis of phloroglucinol containing natural products was synthesized. Key steps include a manganic acetate-mediated cyclization and the facile conversion of an alkene into a β-bromoenone. 相似文献