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《普通高中化学课程标准(2017年版)》强调STSE教育理念。通过对苹果中铁元素、氧气、多酚氧化酶活性对苹果褐变现象影响的实验探究,为提高苹果的使用价值以及食品保鲜技术提供了理论基础,让学习者在"苹果"中感受化学知识的生活化及科学知识的价值。 相似文献
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手性膦酸二酯类化合物的合成与结构 总被引:3,自引:0,他引:3
手性呋喃酮1a1b与亚磷酸三酯2a2b通过串联的不对称Michael加成/分子内Michalis-Arbazov重排反应,得到含磷官能团的新手性化合物5-(S)-(1S)-冰片氧基-4-膦酸二酯基-3-卤素-2(5H)-呋喃酮(3a~3d).该反应具有条件温和,产率高(69%~93%),光学纯度单一(d.e.≥98%)等特点.通过元素分析,IR,UV1HNMR13CNMR,MS,[α]D20等分析数据以及X射线四圆衍射确定了它们的化学结构和绝对构型. 相似文献
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采用液相合成法,以二茂铁甲酸、氧化型谷胱甘肽(GSSG)为原料,苯并三唑-1-四甲基六氟磷酸酯(HBTU)及1-羟基苯并三唑(HOBt)为缩合剂,合成了具有电活性的目标化合物氧化型谷胱甘肽-二茂铁(Fc-GSSG-Fc),其收率为46%,并对其进行了表征。目标化合物Fc-GSSG-Fc的循环伏安扫描结果表明,在0~0.8V范围内出现了一对可逆的氧化还原峰,氧化峰和还原峰电位分别为0.459和0.391V;峰电位之差ΔEp为68mV,峰电流密度之比Ipa/Ipc为1.02,扩散系数D0=1.175×10-8cm2·s-1。利用电化学方法研究了Fc-GSSG-Fc与Zn(Ⅱ)之间的配位特性。实验结果表明,Fc-GSSG-Fc与Zn(Ⅱ)形成了1:1的配合物。 相似文献
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The stereocontrolled synthesis of the C(17)--C(28) fragment 3 of didemnaketal B was accomplished in 21 steps from the natural (R)-(+)-pulegone and (S)-(--)-citronellal. The key steps involved diastereoselective construction of two chiral carbon centers through the intramolecular chiral induction and uncommon Julia olefination of ketone forming the E-trisubstituted C(22)--C(23) double bound. 相似文献
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The asymmetric reaction of the chiron 2(5H )-furanones (4a-4c) with the Horner-Emmons reagents (5a-5b) has been investigated. The newly chirai organophosphorus derivatives 6 and 7 were obtained using the phosphoryl-stabilized carbanion as a building block in DMSO under mild conditions. Through the asymmetric introduction, the Horner-Emmons reagent could be transformed to a chiral building block to afford the novel functionalized phosphorus derivatives. The structures of the synthesized compounds 6 and 7 were identified on the basis of their elementary and spectroscopic data, such as IR,^1H NMR, ^13C NMR, MS and X-ray crystallography. These resuits provided a valuable approach to the synthesis of potentially interesting chirai organophosphorus derivatives and probing their biological activities. 相似文献
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2'''',7''''-二氯荧光素荧光法测定环境样品中微量As(Ⅲ)的研究 总被引:1,自引:0,他引:1
本文报道了以2',7'-二氯荧光素为指示剂,荧光法间接测定微量As3+的新方法.在pH=5.5~7.5中性缓冲介质中,I2与2',7'-二氯荧光素反应,使2'7'-二氯荧光素的荧光猝灭,当加入As3+与I2反应使体系荧光增强,体系激发波长和发射波长分别为λex=508 nm,λem=524 nm.As3+含量在1.0~80 μg·L-1范围内呈良好线性关系,检测限为1.0 μg·L-1.该方法灵敏度高,选择性好,用于工业废水和河水样品微量As3+的测定,结果满意. 相似文献