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11.
12.
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
13.
Anufriev V. Ph. Polonik S. G. Pokhilo N. D. Balanyova N. N. 《Russian Chemical Bulletin》2003,52(10):2247-2250
The Friedel—Crafts acylation of trimethylhydroquinone, 3,5-diethyl-2-hydroxyhydroquinone, and 3,5-diethyl-1,2,4-trimethoxybenzene with dichloromaleic or citraconic anhydride in an AlCl3—NaCl melt is accompanied by o-C-dealkylation to afford functionally substituted naphthazarins. 相似文献
14.
2-Chloro-1,4-naphthoquinone was covalently attached to six differently substituted and positional isomers of trans-aminostilbene, forming a novel donor-acceptor system (QST), in which a good fluorophore is bonded via an NH group to an active redox quencher. The new systems were characterized by FT-IR, 1H NMR, HR-MS, UV-Vis and fluorescence spectroscopy. The redox state of the system QST/QH2ST controls its photochemical properties. While the QST's behave as an ‘auto-quenching system’ and are non-fluorescent, the reduced hydroquinonic system (QH2ST) affects appreciably the emission properties of the molecule. 相似文献
15.
邻对苯二酚的合成方法 总被引:4,自引:1,他引:4
用自制的钛硅沸石TS-1为催化剂,对H2O2存在下苯酚直接羟基化合成邻、对苯二酚的反应条件,主要影响因素及机理进行了探讨,发现该民传统的合成方法相比,反应的选择性及转化率较高,工艺简单,成本低和污染少。 相似文献
16.
Yi HB Diefenbach M Choi YC Lee EC Lee HM Hong BH Kim KS 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(18):4885-4892
To understand the self-assembly process of the transition metal (TM) nanoclusters and nanowires self-synthesized by hydroquinone (HQ) and calix[4]hydroquinone (CHQ) by electrochemical redox processes, we have investigated the binding sites of HQ for the transition-metal cations TM(n+)=Ag(+), Au(+), Pd(2+), Pt(2+), and Hg(2+) and those of quinone (Q) for the reduced neutral metals TM(0), using ab initio calculations. For comparison, TM(0)-HQ and TM(n+)-Q interactions, as well as the cases for Na(+) and Cu(+) (which do not take part in self-synthesis by CHQ) are also included. In general, TM-ligand coordination is controlled by symmetry constraints imposed on the respective orbital interactions. Calculations predict that, due to synergetic interactions, silver and gold are very efficient metals for one-dimensional (1D) nanowire formation in the self-assembly process, platinum and mercury favor both nanowire/nanorod and thin film formation, while palladium favors two-dimensional (2D) thin film formation. 相似文献
17.
Fast and sensitive high performance liquid chromatography analysis of cosmetic creams for hydroquinone, phenol and six preservatives 总被引:1,自引:0,他引:1
A fast and sensitive HPLC method for analysis of cosmetic creams for hydroquinone, phenol and six preservatives has been developed. The influence of sample preparation conditions and the composition of the mobile phase and elution mode were investigated to optimize the separation of the eight studied components. Final conditions were 60% methanol and 40% water (v/v) extraction of the cosmetic creams. A C18 column (100 mm × 2.1 mm) was used as the separation column and the mobile phase consisted of methanol and 0.05 mol/L ammonium formate in water (pH=3.0) with gradient elution. The results showed that complete separation of the eight studied components was achieved within 10 min, the linear ranges were 1.0-200 μg/mL for phenol, 0.1-150 μg/mL for sorbic acid, 2.0-200 μg/mL for benzoic acid, 0.5-200 μg/mL for hydroquinone, methyl paraben, ethyl paraben and propyl paraben, butyl paraben, and good linear correlation coefficient (≥0.9997) were obtained, the detection limit was in the range of 0.05-1.0 μg/mL, the average recovery was between 86.5% and 116.3%, and the relative standard deviation (RSD) was less than 5.0% (n=6). The method is easy, fast and sensitive, it can be employed to analyze component residues in cosmetic creams especially in a quality control setting. 相似文献
18.
The hydroquinone-dimethyl sulfoxide-toluene system was investigated by thermal and X-ray diffraction analyses. The crystal structure of the 1:1 complex of hydroquinone with dimethyl sulfoxide was determined. Crystal data: C8H12O3S, M = 188.24, triclinic system, space group P1¯, unit cell parameters: a = 7.4202(2) Å, b = 8.4046(3) Å, c = 8.7340(3) Å; α = 100.830(1)°, β = 99.794(1)°, γ = 114.129(1)°; V = 469.35(4) Å3, Z = 2, d calc = 1.332 g/cm3, R1 = 0.028, T = 100 K. The molecules are linked in a supramolecular assembly via D-H...A hydrogen bonds (D = O, C; A = O, π). 相似文献
19.
Luis Cabrales Karla Calderon Irvin Hinojosa Felipe Valencia Noureddine Abidi 《International Journal of Polymer Analysis and Characterization》2016,21(8):718-727
Oils and fats derived from animals and plants provide a good renewable source for polymer precursors. In this investigation, fatty acids derived from plant oils and diols were used as monomers to produce polyesters by melt polycondensation. Sebacic acid, hexanediol, and hydroquinone were used as precursors in the polymer synthesis. The polymers were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, three-bending point flexural test, X-ray diffraction, tensile testing, and contact angle. The resulting polyesters were blended with epoxies to create materials with an increased elongation at break without affecting other mechanical properties. 相似文献
20.
Boris Pejin Carmine Iodice Vesna Kojic Dimitar Jakimov Milica Lazovic Giuseppina Tommonaro 《Natural product research》2016,30(11):1293-1296
The cytotoxicity of avarol, a main secondary metabolite of the Mediterranean sponge Dysidea avara, was in vitro screened by MTT assay against four human tumour cell lines. The colon HT-29 tumour cells practically showed to be the only sensitive ones towards this organic compound. No toxicity was found against the fetal lung fibroblast MRC-5 cells at the concentrations tested. In comparison with doxorubicin, used as a positive control, avarol actually exhibited at least 588-fold less toxicity towards normal MRC-5 cells. Finally, comet assay indicated that DNA fragmentation was almost fivefold higher upon the treatment with doxorubicin, compared to avarol. The obtained results have actually confirmed that avarol scaffold may contribute to development of new cytostatics inspired by nature. 相似文献