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以五甲基二乙烯三胺(PMDETA)、脂肪醇聚氧乙烯醚(FAPOE)和环氧氯丙烷(ECP)为原料,分两步合成了一种含聚氧乙烯醚链三头季铵盐的表面活性剂。对反应影响因素、产物结构与部分性能进行了分析与表征。结果表明:第一步反应n(ECP):n(FAPOE)为2.5~3:1,溶剂为正己烷,四丁基溴化铵作相转移催化剂,无水K2CO3作缚酸剂,时间6~8h。第二步反应n(中间体):n(PMDETA)为3.5—4.0:1,溶剂为正丁醇,时间40-45h;溶剂与时间是主要影响因素。定性表征符合产物结构:定量表征n(Cl^-):n(阳离子部分)为3.4:1,略高于理论值。产物的表面活性高,1.0×10^-4mol/L水溶液的表面张力可降至6.65mN/m。 相似文献
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应用等离子共振吸收光谱和扫描电子显微镜,观察了碘和盐酸四环素反应引起的金纳米棒形态的变化.实验表明,单质碘能对金纳米棒产生融合作用,引起金纳米棒径向比的减小和纵向吸收波长的蓝移;但当盐酸四环素存在时,单质碘与盐酸四环素作用,减低了碘的有效浓度,减弱了碘对金纳米棒的融合作用,使金纳米棒的纵向吸收峰随盐酸四环素浓度的增大发生线性红移.据此本文建立了一种测定盐酸四环素的方法.方法的线性范围为5.0×10^-5mol/L~5.0×10^-4mol/L,检测限为2.4×10^-6mol/L(3σ/k).常见物质不干扰测定.方法成功应用于合成样中四环素测定,回收率在92.8%~107.2%之间,RSD值小于4-3%.用标准加入法测定了3个乳制品厂生产的牛奶中盐酸四环素,表明牛奶中的四环素残余物浓度较低,符合安全标准. 相似文献
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研究了影响Fe(OH)3进行酸式电离反应的因素,在多种浓度和温度条件下的NaOH浓溶液中采用SnO2-Sb2O3/Ti电极,研究FeO4^2-/FeO2^-体系的电化学氧化还原反应参数及其变化趋势,结果证实该体系发生电化学氧化还原反应的最佳碱溶液浓度范围为12—14mol/L,最佳温度范围为295~315K.阐明了在实验条件下FeO4^2-/FeO2^-氧化还原体系中存在由FeO4^2-/FeO2^-构成的氧化还原电对,而FeO2不直接与FeO2构成氧化还原电对;并给出了FeO4^2-/FeO2^-氧化还原体系的Latimer图. 相似文献
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锌跟硫酸铜溶液反应.在锌粒表面生成一层黑色粉状物。通过实验证实,黑色粉状物是铜、氧化铜和锌粉的混合物。氧化铜的生成.是硫酸铜水解生成氢氧化铜,氢氧化铜分解生成氧化铜。锌跟硫酸铜溶液反应,要观察到紫红色铜的生成,就要抑制水解,把硫酸铜配成饱和溶液。 相似文献
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砷锑铋对阴极铜沉积过程的影响 总被引:6,自引:0,他引:6
用线性电位扫描、XPS、XRD等方法,研究了砷锑铋离子对酸性硫酸铜系统中铜沉积反应动力学及铜沉积层成份与结构的影响.研究表明:As(Ⅴ)离子能增大铜沉积反应的交换电流密度,对铜沉积过程起去极化作用;Sb(Ⅲ)、Bi(Ⅲ)离子均使铜沉积反应交换电流密度减小,对铜沉积过程起极化作用;但砷锑铋离子不改变铜沉积反应的机理.测试表明:用200A/m2电流密度电解,砷锑铋不会在阴极沉积,也不影响铜沉积层的晶面择优取向(220);用1500A/m2电流密度电解,发现砷与铋在阴极与铜共沉积,铜沉积层的晶面择优取向变为(111),沉积层中铜主要以金属Cu和少量Cu2O形式存在,铋主要以Bi2O3形式存在. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives. 相似文献
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The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions. 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献