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甲烷磺酸盐的合成、表征及其催化酯化反应的性能 总被引:15,自引:0,他引:15
Methane-sulfonate of copper, cobalt, zinc, lanthanide, praseodymium and neodymium are synthesized and characterized by FTIR and TGA. Methane-sulfonates are used as the catalysts in the esterification of chloroacetic acid with isopropanol. Catalytic activity of methane-sulfonates is studied and compared with other Lewis acids. Under the condition of 1.2/1 molar ratio of isopropanol to chloroacetic acid, 1% catalyst (molar percent of chloroacetic acid), 2.5h reaction time, 80~85℃ temperature and benzene as water-carrying agent. The experi-mental results showed that catalytic activity of Lanthanide methane-sulfonate was the best, the yield of isopropyl chloroacetate reaches 88.7%. Copper methane-sulfonate can be reused for three times without distinct loss of catalytic activity. 相似文献
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基于TGA-FTIR联用技术的EVA热解研究 总被引:7,自引:0,他引:7
采用热重-傅里叶变换红外光谱联用技术研究了在N2气氛下乙烯-乙酸乙烯酯共聚物(EVA)的热稳定性及其分解失重情况;实验首先单独使用热重分析仪考察了EVA在不同升温速率下的失重情况;然后采用热-红联用技术对EVA失重过程中的逸出气体进行考察;由实验结果可以明显地看出,EVA的分解失重分为两个阶段,并且随着升温速率的增大EVA的起始失重温度有所增加;第一个失重阶段所放出的气体经傅里叶变换红外光谱扫描并与标准气相谱库中乙酸的标准红外谱图对照后确定为乙酸,第二个失重阶段是由于碳氢链段的分解而引起的;最后根据升温速率为5℃/min时EVA第一个失重阶段的失重率计算得出EVA样品中乙酸乙烯酯的含量为31.8%(ω)。 相似文献
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采用改进的固相法, 以K2CO3和氢氧化钽为原料, 通过添加KF, 在相对低温下制备了单一钙钛矿结构的KTaO3. KF的加入抑制了烧绿石相的生成, 通过水洗可脱除KF. 使用X射线衍射仪(XRD), 扫描电子显微镜(SEM)和紫外-可见(UV-Vis)漫散射光谱仪对不同温度下制备的产物进行了表征. 结果表明, 各个温度下制备的产物均是由粒径在10~30 nm范围内的粒子聚集成的大颗粒; 500, 600和800℃制备的产物带隙分别为3.68, 3.63和3.54 eV. 进一步考察其它碱金属卤化物对产物结构的影响发现, LiF, NaF和KF的作用相同; 当添加碱金属氯化物时, 主要产物分别是钽酸锂、 钽酸钠和烧绿石结构的钽酸钾. 相似文献
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草酸铽与水合环己烷六酸(H6LⅠ.H2O)(顺式椅式构型LⅠ:a,e,a,e,a,e)在水热条件下反应生成一种新颖的三维稀土配位聚合物[Tb4(LⅡ)(ox)3(H2O)8](LⅡ为反式椅式构型:e,e,e,e,e,e;ox为草酸根),通过元素分析和红外光谱对这个配位聚合物进行了表征。X射线单晶衍射分析表明该配合物属于三斜晶系,P1空间群,晶胞参数为:a=0.60203(4)nm,b=1.08278(8)nm,c=1.29446(9)nm,α=67.908 0(10)°,β=82.109 0(10)°,γ=83.887 0(10)°,V=0.773 07(9)nm3,Z=2。在这个配合物的形成中,顺式构型的H6LⅠ配体发生构型转变形成LⅡ配体,LⅡ配体采取μ8-桥连模式将Tb离子连接成一个具有孔洞的二维(Tb-LⅡ)配位层。由μ2-和μ4-桥连模式构成的一维(Tb-ox)链将二维(Tb-LⅡ)层连接成一个具有孔道的三维配位框架,ox配体和水分子通过配位作用和氢键作用填充在孔道中。 相似文献
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Recently, the investigation of novel molecularly imprinted polymers(MIPs) has attracted a lot of interest and becomes a fascinating field. The phenobarbital(PHN) was taken as an imprinted molecule and the 2-vinyl-4,6-diamino-1,3,5-triazine(VDAT) was considered as a functional monomer in this study. The geometry optimization, natural bond orbital(NBO) charge, and molecular electrostatic potential(MEP) of PHN and VDAT were studied at the M062 X level belonging to one of the hybrid density functional theories. Furthermore, we discussed the bonding conditions of PHN molecular imprinted polymers(PHN-MIPs) via the hydrogen bond length and atoms in molecules(AIM) theory. The rebinding property of PHN-MIPs was also researched. The results of MEP and NBO charge analysis were coincident. The stability property was excellent when the ratio of PHN and VDAT was 1:4. Except the classic hydrogen bonds, non-classical hydrogen bonds also existed in the imprinted polymers. By simulating the rebinding energies between the pentobarbital(PNT), barbital(BAR), and PHN-MIPs after the elution of PHN, the rebinding property of PHN-MIPs to PHN was excellent when PNT and BAR existed all at once. This research can provide theoretical reference for the synthesis and characterization of novel PHN-MIPs. 相似文献
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为建立一种简单高效的中药活性成分的提取分离、定性鉴定、含量测定以及降血糖活性研究的新方法,采用绿色无毒的水提酸沉法提取了黄芩的活性成分—黄芩苷,通过薄层色谱法做定性鉴定和紫外分光光度法测定其含量,构建一个高效的电化学葡萄糖传感器,并建立一种基于电化学安培法的降血糖活性研究新方法。以临床降糖药阿卡波糖论证了电化学安培法检测葡萄糖淀粉酶抑制活性的可靠性和稳定性,并成功应用于黄芩苷的降血糖活性研究。结果表明,黄芩苷具有较好的葡萄糖淀粉酶抑制活性,其半数抑制浓度(IC_(50))为0.056 g/L。本研究为从天然药物中提取分离降血糖活性成分提供了一种新颖的研究方法。 相似文献