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31.
恒电流库仑分析法测定硫酸亚铁铵等基准试剂的纯度 总被引:1,自引:0,他引:1
在1.8mol/L硫酸介质中,以恒电流通过含有Mn^2+的电解质溶液,使工作电极铂阳极上电生出Mn^3+,Mn^3+与溶液中待测基准试剂硫酸亚铁铵、草酸钠或草酸定量反应,以永停终点法确定库仑滴定终点,通过测量电解电流及电解时间,利用法拉弟电解定律计算基准试剂的纯度。该方法的相对误差为0.32%~0.36%,测量结果的相对标准偏差为0.045%-0.050%(n=11)。 相似文献
32.
Rainer Beckert Margit Gruner Ingeborg Seidel Ralf-Jürgen Kuban 《Monatshefte für Chemie / Chemical Monthly》1989,120(12):1125-1137
Summary Arylsubstituted oxalic bis-imidochlorides1 react with thiosemicarbazones of type5 as well as13 to give five-membered-ring heterocycles8,11, and16.13C-NMR spectroscopy, chemical methods and X-ray crystallography have been used to investigate the nature of the structures obtained. The13C-chemical shifts of13 and imidazolidines16 are correlated with Hammett
p
constants and dual substituent parameters to evaluate the transmission of theX substitutent electronic effects via the side-chain iminyl carbon atom into the heterocyclic ring and its neighbouring phenyl groups. 相似文献
33.
化学改性对催化裂化催化剂氢转移性能的影响 总被引:9,自引:0,他引:9
研究了用草酸处理裂化催化剂的活性组分USY型分子筛以及在催化剂基质中添加磷改性的氧化铝等方法对裂化催化剂氢转移反应活性的影响. 实验结果表明,酸处理能脱除USY型分子筛孔道中的无定形氧化铝,疏通分子筛孔道,提高分子筛的氢转移反应活性,减少积碳; 对于含稀土的REUSY型分子筛,酸处理首先脱除的是稀土离子,降低了分子筛的裂化反应活性,但提高了氢转移反应活性. 在催化剂基质中添加磷改性的氧化铝能增加基质的弱酸性中心,增加裂化反应的活性中心,提高催化剂的裂化及氢转移反应活性,同时减少催化剂上的积碳. 相似文献
34.
35.
Jianhui Yan Qiang Liu Luxiong Guan Feng Liang Haojie Gu 《Frontiers of Chemistry in China》2009,4(2):121-126
The Pt-Sr(Zr1 − x
Y
x
)O3 − δ
-TiO2(Pt-SZYT) heterojunction photocatalysts were prepared by a photodeposition method. The composite particles were characterized
by XRD, SEM, UV-Vis DRS, and PL techniques. Photocatalytic hydrogen generation in H2C2O4 aqueous solution under the irradiation of simulated sunlight was used as a probe reaction to evaluate the photocatalytic
activity of the photocatalysts. The effects of the content of Pt loading and the concentration of oxalic acid on the photocatalytic
activity of the catalyst were discussed. The continuous photocatalytic activity of the Pt-SZYT and the relationship between
PL intensity and hydrogen generation were also discussed. The results show that Pt-SZYT catalysts had high photocatalytic
activity of hydrogen generation. The content of Pt loading and the concentration of oxalic acid have important influence on
the photocatalytic hydrogen generation. The optimal loading content of platinum was 0.90 mass%. Under this condition, the
average rate of photocatalytic hydrogen generation was 1.68 mmol·h−1 when the concentration of oxalic acid was 50 mmol·L−1. The higher the photocatalytic activity, the weaker the PL intensity, which was demonstrated by the analysis of PL spectra.
__________
Translated from Acta Chimica Sinica, 2008, 61 (in Chinese) 相似文献
36.
37.
A new 1D chain coordination polymer [Cd(dpq)(ox)0.5Cl]n(1) (dpq=dipyrido[3,2-d:2′,3′-f]quinoxaline and ox=oxalate) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR and single crystal X-ray diffraction analysis. Compound 1 (CdClC15H8N4O2): monoclinic, space group P21/c, a=0.854 04(5) nm, b=2.094 90(13) nm, c=0.839 22(5) nm, Z=4, V=1.438(15) nm3, Mr=424.11, Dc=1.959 g·cm-3, F(000)=828.0, μ=1.719 mm-1, S=1.028, the final R=0.025 8 and wR=0.057 5. The crystal structure analysis indicates that the cadmium ion is coordinated by two oxygen atoms from a oxalate, two chelating nitrogen atoms from a dpq molecule and two Cl- anions. The adjacent Cd(Ⅱ) ions are linked by Cl- anions and oxalate ligands in alternate sequence to form a 1D chain coordination polymer and the adjacent chains are further connected by π-π stacking interactions to form a 2D supramolecular network. Moreover, the title compound exhibits blue emission in the solid state at room temperature. CCDC: 680748. 相似文献
38.
GE Shu-Sheng ;WU Xiu-Mei ;LIU Qing-Xiang ;ZHENG Zhan-Ying ;ZANG Yan ;LIU Shu-Wen ;FENG Jin-Cheng 《结构化学》2008,(12):1538-1542
A novel Cu(Ⅱ) complex has been prepared by means of self-assembly of CuCl2, 1-hexylimidazole L and oxalic acid (H2OX) in the presence of triethylamine, and structurally characterized by X-ray diffraction analysis. In complex 1, 1-D polymer chains are formed through pentacoordinated Cu(Ⅱ), oxalate and bridging chlorine atoms. In the crystal packing of 1, the imidazole ring head-to-tail π-πstacking interactions exist between 1-D polymer chains and extend the 1-D polymer chains into 2-D supramolecular layers. The fluorescence emission spectra of L and 1 were described. 相似文献
39.
本文利用室内低温反应装置研究了在模拟太阳光-Fe3+-草酸作用下冰相中对氯苯酚(4-CP)的光转化。结果表明,Fe3+-草酸存在条件对冰相中4-CP的光转化有促进作用。Fe3+和草酸初始浓度、Fe3+与草酸的初始浓度比以及初始pH值对体系中4-CP的转化率具有较大影响。当溶液初始pH值为6.50,Fe3+和草酸的初始浓度比是1/5,草酸初始浓度为0.80mmol/L时,4-CP光照7.5h转化率可达39.1%。在光转化过程中,TOC的转化率滞后于4-CP的光转化率。4-CP的光转化符合一级动力学模型。分别利用直接萃取法和衍生化法富集了反应中间产物,并采用GC-MS进行了分析,据此推断了冰相中模拟太阳光-Fe3+-草酸作用下4-CP光转化的反应机理。 相似文献
40.
An efficient one-pot method for synthesis of an array of 3,4-dihydroquinazolin-4-ones from anthranilicacid, triethyl orthoformate, and anilines using oxalic acid as a catalyst was described. The present protocol offers improvements for the synthesis of 3,4-dihydroquinazolin-4-ones with regard to short reaction time, high yields of products, and simplicity in operation. 相似文献