共查询到18条相似文献,搜索用时 109 毫秒
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2,4-二氯苯氧乙酸合成实验中制备苯氧乙酸一步,教材上是以氯乙酸和苯酚为原料,在碱性条件下进行Williamson反应。教材所述实验方法,存在氯乙酸的水解和苯酚的氧化等问题,导致产品质量差、收率低。对该实验采取以下改进措施:采用0℃下中和氯乙酸;加入苯酚的同时加入1%亚硫酸钠;苯酚与氢氧化钠作用后,再加入到氯乙酸钠溶液中。改进后的实验,不但提高了苯氧乙酸产品的质量,而且收率可达95.2%。 相似文献
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薄层扫描法分离和测定苯氧乙酸和2,4-二氯苯氧乙酸 总被引:5,自引:0,他引:5
苯氧乙酸及其衍生物对植物有很强的生物活性,是一类药性高、选择性好、使用安全的化学除草剂,因此,被农田广泛应用.其中2,4-二氯苯氧乙酸(简称2,4-D)是最为常用的一种.虽然这类化合物的毒性较小,但在土壤、粮食、环境水中的残留,也会对动植物构成不同程度的危害.因此,对苯氧乙酸类除草剂的分离和测定方法的研究,对于保护人类的健康和生态平衡具有重要的意义.目前,国内尚未见到有关这方面的研究报道.我们采用薄层色谱法,同时分离和测定了苯氧乙酸和2,4-D,灵敏度高,操作简便、快速. 相似文献
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具有激素活性的Schiff碱化合物的研究(Ⅰ)──苯氧乙酸类Schiff碱的合成及其生物活性汪焱钢,叶文法,尹大学,黄君珉,陆爱红(华中师范大学化学系,武汉,430070)关键词Schiff碱,氨基苯氧乙酸,植物激素活性芳胺的Schiff碱类化合物,... 相似文献
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以苯氧乙酸(Hpa)、对硝基苯氧乙酸(Hpnpa)和对甲基苯氧乙酸(Hpmpa)为原料,分别与2-氨基苯并噻唑(aben)和乙酸铜反应,合成了3种铜配合物[Cu(pa)2(aben)2](1),[Cu2(pnpa)4(aben)2](2)和[Cu(pmpa)2(aben)2].[Cu2(pmpa)4(aben)2](3),并通过元素分析、红外光谱和单晶X-射线衍射对其结构进行了表征。结果表明,3种配合物具有不同的配位模式,配合物1的中心Cu(Ⅱ)分别与2个羧基氧原子和2个噻唑环上的氮原子配位;配合物2的2个Cu(Ⅱ)则分别都与来自4个不同配体的羧基氧原子和1个噻唑环上的氮原子配位,从而在分子中形成了2个近乎垂直的八元环;配合物3为混配型化合物,1个Cu(Ⅱ)的配位数为4,另外2个Cu(Ⅱ)的配位数为5,参与配位的配体原子分别与配合物1和2相同。最低抑菌浓度的测定结果表明,3种配合物对真菌都表现出良好的抑制作用,且由于苯氧乙酸配体中取代基种类的不同,而使得配合物的抗菌效果出现明显的不同。 相似文献
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固相萃取富集高效液相色谱法测定苯氧乙酸和2,4—二氢苯氧乙酸 总被引:1,自引:0,他引:1
建立了以固相萃取技术进行富集,高效液相色谱法进行分离和检测苯氧乙酸和2,4-二氯苯氧乙酸的方法。环境水中的苯氧乙酸和2,4-二氯苯氧乙酸用Sep-Pak C18 Cartridge进行固相萃取。液相色谱的条件是:Shim-Pack CLC ODS柱为分析柱;甲醇-水(9:1,V/V)为流动相;流速为1mL/min;在UV-275nm波长下进行检测。本法具有良好的灵敏度和重现性。 相似文献
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将水杨醇和苯氧乙酸酯化得到了8个新的化合物, 所有化合物经过元素分析和1H NMR确认. 除草活性的初步测试结果表明, 化合物6具有较好的除草活性. 相似文献
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Karthikeyan B Saravanan B 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(3):619-623
Raman spectra of phenoxyacetic acid and chlorine substituted phenoxyacetic acids viz., o-chlorophenoxyacetic acid, p-chlorophenoxyacetic acid and 2,6-dichlorophenoxyacetic acid have been analysed with the aid of abinitio theoretical calculations. The effect of chlorine substituents on the Raman spectra of phenoxyacetic acid have also been analysed by considering some important vibrational modes. 相似文献
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Tiantian Si Lei Liu Xiaojing Liang Huixiao Duo Licheng Wang Shuai Wang 《Journal of separation science》2019,42(12):2148-2154
A zirconium(IV)‐based metal–organic framework material (MOF‐808) has been synthesized in a simple way and used for the extraction of phenoxyacetic acids in complex samples. The material has good thermal and chemical stability, large specific surface area (905.36 m²/g), and high pore size (22.18 Å). Besides, it contains a large amount of Zr‐O groups, easy‐to‐form Zr‐O‐H bond with carboxyl groups of phenoxyacetic acids, and possesses biphenyl skeleton structure, easy to interact with compounds through π‐π and hydrophobic interactions. These characteristics make the material very suitable for the extraction of certain compounds with a high extraction efficiency and excellent selectivity. The extraction conditions were optimized, and then an analytical method was successfully established and applied for analysis of actual samples. The solid‐phase extraction method based on prepared material had a wide linear range of 0.2–250 μg/L and a low detection limit of 0.1–0.5 μg/L for four phenoxyacetic acid compounds including 2,4‐dichlorophenoxyacetic acid, 2‐(2,4‐dichlorophenoxy) propionic acid, 4‐chlorophenoxyacetic acid, and dicamba. The relative standard deviations of intra‐ and interday precision were 1.8–3.8 and 4.3–6.9%, and the recoveries after spiking were between 77.1 and 109.3%. The results showed that the material is a desired substituent for the extraction of compounds with benzene ring structure containing carboxyl groups. 相似文献
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Tokuko Takajo Kazunori Tsuchida Azusa Yokota Ichiro Koshiishi 《Biomedical chromatography : BMC》2010,24(7):794-797
Nitroxyl radicals can trap fatty acid allyl radicals on ferric‐lipoxygenases at lower oxygen content, which are an intermediate in the lipoxygenase reaction. In the present study, we examined whether nitroxyl radical‐trapping of fatty acid allyl radicals on the enzyme proceeds in biological fluids with abundant antioxidants. The fatty acid allyl radical–nitroxyl radical adducts were quantified by HPLC with electrochemical detection (HPLC‐ECD); the adducts in eluate degraded into nitroxyl radical by passing through heating coil at 100°C, and then nitroxyl radical was detected by electrochemical detector. Soybean 15‐lipoxygenase and nitroxyl radical (3‐carbamoyl‐2,2,5,5‐tetramethyl‐3‐pyrroline‐N‐oxyl, CmΔP) were mixed with rat serum prepared from fresh venous blood, and the solution was stood at 37°C for 1 h. One volume of the solution was mixed with 5 vols of cold acetonitrile. After centrifugation, the supernatant was subjected to HPLC‐ECD. Arachidonate allyl radical–CmΔP adducts as well as linoleate allyl radical–CmΔP adducts were detected in the solution, and the content of these adducts remarkably increased in the presence of phospholipase A2. It is proved for the first time that nitroxyl radical traps fatty acid allyl radicals generated in the lipoxygenase reaction in biological fluid without competition from endogenous antioxidants. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Hui Yuan Xuejun Yu Bowei Shen Farong Zhang Wenxiu Jiang Zhiquan Pan Hong Zhou 《先进技术聚合物》2020,31(8):1776-1782
This work describes the preparation of a novel solid acid, poly (styrene‐co‐allyl sulfonic acid) (St‐SAA), and its activity test for extracting diosgenin from Dioscorea Zingiberensis C.H. Wright (DZW). The solid acid was synthesized by the radical polymerization of styrene and sodium allyl sulfonate in water/ethanol solution, followed by the acidification. The prepared solid acid was characterized by infrared spectrum (FTIR), thermogravimetric analysis (TGA), X‐ray photoelectron spectroscopy (XPS), element analysis, and scanning electron microscope. The solid acid catalyst was used to extract diosgenin from DZW. It was found that the alcoholysis activity of the solid acid was higher than the hydrolysis activity of sulfuric acid with the same mass under the same conditions. Besides, the solid acid can be separated from the reaction mixture for the recycling extraction of diosgenin, and the solid acid has no loss of mass and no decrease of alcoholysis activity after repeated cycles. 相似文献
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对12种苯氧乙酸化合物的电子轰击质谱进行了系统研究,总结了相应的碎裂规律,讨论了取代基的影响,同时利用串联质谱的低能碰撞诱导解离(CID)、联动扫描(B^2/E)和同位素标记技术研究了硝基苯氧乙酸异构体的主要碎片离子的单分子质变碎裂,并对其形成过程进行了探讨。 相似文献
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Whei Oh Lin Maria C. Bastos Vieira de Souza Antonio P. Altoé Helmut G. Alt 《Monatshefte für Chemie / Chemical Monthly》1983,114(3):359-363
A series of ether-esters containing multidentate components have been prepared from phenoxyacetic acid. The ligands were synthesized from the appropriate phenoxyacetic acid chloride and various alcohols. Four types of new compounds have been obtained. 相似文献