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采用氧化还原剂和偶氮类化合物组成的复合引发体系,通过水溶液聚合法制备丙烯酰胺(AM)和甲基丙烯酰氧乙基三甲基氯化铵(DMC)的共聚物。研究了氧化还原剂总质量分数、氧化剂与还原剂的质量比、偶氮类化合物的种类和质量分数、引发温度、pH值、单体质量分数等对产物特性粘数的影响。得到的较佳工艺条件:氧化还原剂总质量分数0.015%、氧化剂与还原剂质量比0.7、偶氮类化合物质量分数0.012 5%、引发温度25℃、pH值6.0、单体质量分数45%,在上述条件下,产物特性粘数为12.370 8 dL/g。用红外光谱技术对产物的结构进行表征。 相似文献
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首次报道了可作为点击逐步聚合单体、具有不同长度间隔链的末端炔基偶氮苯类化合物的合成。首先以对羟基苯甲酸与苯酚反应制备偶氮苯原料化合物,然后以3-溴丙炔与二醇类化合物制备不同长度的末端炔基间隔链,通过其对偶氮苯原料化合物的修饰制备目标产物。所得目标产物化学结构经1HNMR、13CNMR、FT-IR、元素分析和质谱确证。利用示差扫描量热法(DSC)及偏光显微镜(POM)研究其相转变性能,结果表明,通过改变化合物间隔链长度可以调节其相转变性能,包括相变温度及液晶性能。 相似文献
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以取代苯胺为原料,经重氮化后与取代苯酚偶联合成了5个偶氮苯酚类化合物,产物经FTIR、1 HNMR表征。结果表明,产物结构与预期一致。 相似文献
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2-噻唑偶氮-5-二甲氨基苯甲酸类有机试剂氢离解常数的测定 总被引:4,自引:0,他引:4
用分光光度法测定的三个噻唑偶氮二甲氨基苯甲酸化合物的氢离解常数如下:Ⅰ.2-(5-甲基噻唑)偶氮-5-二甲氨基苯甲酸,pK_1=4.80,pK_2=1.91;Ⅱ.2-(4,5-二甲基噻唑)偶氮-5-二甲氨基苯甲酸,pK_1=4.78,pK_2=1.89;Ⅲ.2-(苯并噻唑)偶氮-5-二甲氨基苯甲酸,pK_1=4.33,pK_2=1.11。用HMO法来研究不同酸度下各种可能的离子形式,通过计算结果与分光实验数据的对照,判断了离解的过程。 相似文献
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The electrochemical reduction of 2-hydroxy-5-[(4-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(3-sulfophenyl)azo]benzoic acid, 2-hydroxy-5-[(2-sulfophenyl)azo]benzoic acid and 2-hydroxy-5-azo-benzoic acid has been carried out in aqueous solutions at glassy carbon electrode using cyclic voltammetry and chronoamperometry. The position of sulfo substituent relative to azo bridge as well as pH of the solution have significant impact on the electrochemical behavior of these compounds. It has been proposed that these compounds are reduced predominantly as hydrazone tautomers resulting in corresponding hydrazo compounds. The overall electrochemical reduction follows DISP2 mechanism, ultimately leading to the 5-amino salicylic acid and sulfanilic acid. The rate determining step is the homogenous redox reaction between intermediate hydrazo compound and 5-amino salicylic acid quinoneimine. The mechanism is proposed in which activated complex of 5-amino salicylic acid quinoneimine and intermediate hydrazo compound is formed with the simultaneous loss of one proton. 相似文献
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HPLC separation and wavelength area ratios of more than 50 phenolic acids and flavonoids 总被引:1,自引:0,他引:1
W. L. Banwart P. M. Porter T. C. Granato J. J. Hassett 《Journal of chemical ecology》1985,11(3):383-395
Relative retention times and wavelength area ratios for over 50 standard compounds were calculated using reverse-phase HPLC. The standard compounds analyzed included benzoic acids, cinnamic acids, benzene carboxylic acids, acetic acids, coumarins, benzaldehydes and a variety of flavonoid compounds including flavanones, flavones, isoflavones, and their glycosides. Each standard compound was chromatographed by three different gradient elutions. Compounds were detected by UV absorption at 254 nm and 280 nm. Relative retention times with respect to two different internal references and the 254nm: 280nm wavelength area ratio was determined for each standard. Soybean root and seed extracts were analyzed for the presence of the standard compounds using the chromatographic conditions described. 相似文献
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以4-正丙基,4-正戊基取代的双环己基甲酸、联苯甲酸和环己基苯甲酸以及对羟基苯甲醛为原料,用一次酯化、一次氧化的方法(酯化氧化法),合成了4个单酯基芳香酸类化合物:4-〔4-(反-4-丙基环己基)苯酰氧基〕苯甲酸,4〔-反-4-(反-4-丙基环己基)环己酰氧基〕苯甲酸,4-〔反-4-(反-4-戊基环己基)环己酰氧基〕苯甲酸和4-〔4-(4-戊基苯基)苯酰氧基〕苯甲酸,总产率分别为74%,76%,72%和71%。产物结构用IR,MS,1HNMR及元素分析进行了表征,DSC及偏光显微镜测定表明,4个目标化合物具有热致液晶性。 相似文献
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文章选取具有非线性光学活性的偶氮化合物作为研究对象,合成了一组含不同取代基和不同推-拉电子结构的偶氮化合物,并通过红外光谱、紫外-可见吸收光谱、元素分析、核磁共振氢谱等方法对所合成的偶氮化合物结构进行了表征;用单光束Z-扫描的方法对所合成的偶氮化合物的三阶非线性光学性能进行了测试,并结合理论计算分析研究了分子结构对偶氮化合物三阶非线性光学性能的影响。 相似文献
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Tushar S. Basu Baul Pradip Das Asit K. Chandra Sivprasad Mitra Simon M. Pyke 《Dyes and Pigments》2009,82(3):379-386
The structures of several azo-benzoic acids, 4-[((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]benzoic acid along with their precursors 2-hydroxy-5-[(E)-(aryldiazenyl)]benzaldehydes were confirmed using 1H, 13C NMR, UV–VIS and IR spectroscopic techniques. UV–VIS absorption spectra were measured in pure organic solvents while complementary spectroscopic experiments using mixed solvent systems as well as in the presence of base were undertaken to characterize the different species present in solution. Both acid–base dissociation and azo–hydrazone tautomerism occurred in solution, with the extent of the individual equilibria being dependent on the solvent composition and/or pH of the medium. Molecular structures and geometries were optimized using the B3LYP density functional theory method employing the 6-31G(d) basis set. 相似文献
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Takamasa Nonaka Shuuji Maeda Tomonari Ogata Satoko Nakashima Tomonori Kawasaki Seiji Kurihara 《应用聚合物科学杂志》2005,97(5):2097-2104
Resins having phenolic derivatives were prepared by treating a resin (RAS‐4G), having benzylamino groups, with benzoic acids containing phenolic hydroxyl groups. The RAS‐4G was prepared by treating macroreticular chloromethylstyrene‐tetraethyleneglycol dimethacrylate (4G) copolymer beads with potassium phthalimide in N,N‐dimethylformamide, followed by reflux in an ethanol/hydrazine monohydrate mixture. 4‐Hydroxy benzoic acid, (2,4‐, 3,4‐, and 3,5‐)dihydroxy benzoic acids, 3,4,5‐trihydroxy benzoic acid, etc., were used as benzoic acids with phenolic hydroxyl groups. The antioxidation ability of the resins having phenolic derivatives was investigated against the generation of 1,4‐dioxane hydroperoxide. The resins showed high inhibition ability against the generation of hydroperoxide. In particular, the resin (RAS‐4G‐3,4‐DHBA) having two phenolic hydroxyl groups had the highest inhibition ability. The resins were found to act as radical scavengers during the generation of 1,4‐dioxane hydroperoxide by UV irradiation in the presence of oxygen. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2097–2104, 2005 相似文献
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《Dyes and Pigments》2013,96(3):587-599
5-[(3,5-dicarboxyphenyl)azo]-barbituric acid, an azo-based aromatic diacid was prepared and fully characterized by FT IR, 1H and 13C NMR along with UV–vis absorption spectroscopy. The effects of varying pH and solvent upon the absorption spectrum of the azo dye were investigated. The optimized molecular structures of possible tautomeric forms and HOMO–LUMO energies of expecting preferred forms of the synthesized heterocyclic azo dye have been calculated using density functional theory, (B3LYP) methods with TZVP basis set level and Polarizable Continuum Model (PCM) model for solvation effect. The calculations showed that the most probably preferred form of the azo dye in gas phase and solution was a hydrazone-keto form. FT IR and UV–vis spectroscopy, DSC, TGA and XRD techniques were used to obtain the characteristics and structural features of the monomer-synthesized polyamides. The influence of organic solvents on the absorption spectra of the polymers along with viscosity measurements (0.19–0.44 dl/g), solubility and film formability of the synthesized polyamides were also investigated. 相似文献
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设计并合成了6种具有D-π-A型和D-π-A-π-D型共轭结构的双羟乙氨基给体-硝基受体型偶氮化合物,用溶致变色法测算了分子的二阶非线性极化率。实验结果表明,双羟乙氨基和硝基是一对有效的给体、受体组合,它们与偶氮共轭链相连组成的分子具有较大的二阶非线性极化率,其中,具有D-π-A-π-D二维共轭结构的化合物,它包含两条从给体到受体的共轭链,二阶非线性极化率β1 064达到297.4×10(-30)esu,并且这个分子的透明性在6个分子中也是最好的,光学损耗最小。 相似文献