992 resultados para 12-119
Resumo:
双电荷离子[C_(12)H_(12)N_2O]~(2+)和[C_(12)H_(12)N_2S]~(2+)的气相单分子分解反应研究任达,贾维平,李智立,刘淑莹(中国科学院长春应用化学研究所,长春,130022)关键词双电荷离子,质量分析离子动能谱,串联质谱,4...
Resumo:
在氢离子浓度均为3mol/L的硫酸,盐酸,磷酸,醋酸水溶液中和冰醋酸中研究了具有Keggin结构的硅相(SiMo(12))和磷钼(PMo(12))杂多酸在不同来源活性炭上的吸附作用,在酸性介质中,其吸附量均比在水溶液中有所增加,但如果考虑吸附量与体系酸强度之间的关系,实验结果表明,SiMo(12)和PMo(12)之间存在着不同的规律。
Resumo:
在氢离子浓度均为3mol/L的硫酸,盐酸,磷酸,醋酸水溶液中和冰醋酸中研究了具有Keggin结构的硅钨杂多酸(SiW_(12))在不同来源活性炭上的吸附作用。各活性炭对SiW_(12)吸附等温线的形式是不相同的,吸附剂载体的微孔结构以及杂多酸的溶剂化起着重要的作用。并且在无机酸介质中,杂多酸的吸附量比在水溶液中成规律性地增加,且与酸强度成正比关系。在有机酸介质中,吸附作用比较复杂。根据所得结果,提出了在酸性介质中杂多酸在活性炭表面的吸附模型。
Resumo:
In this paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) were used to study the structure and compatibilization of poly(propylene) (PP)/nylon-12 (PA 12) blends. The compatibilizatio
Resumo:
1:12 phosphomolybdic anion doped polypyrrole film electrode was characterized by in-situ UV-vis spectroelectrochemistry, X-ray photoelectron spectroscopy(XPS), scan electronic microscopy(SEM) and electron spin resonance(ESR) spectroscopy.
Resumo:
在乙腈介质中合成了苯并-12-冠-4(简称B-12-C-4)和单环己基-12-冠-4(简称Cy-12-C-4)的六种希土配合物:RE(NO3)3·B-12-C-4(RE=Pr,Gd,Yb,Lu),RE(NO3)3·Cy-12-C-4(RE=La,Lu).研究了它们的IR及1HNMR性质,并测定了四种单晶的结构.用INDO法计算了Lu(NO3)3·B-12-C-4,Lu(NO3)3·Cy-12-C-4的电子结构.结果表明.B-12-C-4与希土的配合物稳定性按Pr,Gd,Yb,Lu顺序减弱,并且Cy-12-C-4与希土的配位能力大于B-12-C-4.发现冠醚分子通过自身不同程度的扭曲,改变冠醚环空穴的大小,实现与不同大小的希土离子的配位作用.
Resumo:
研究了H_4SiW_(12)O_(40)·24H_2O(SiW_(12))在水、乙醇、乙酸、乙酸丁酯中在活性炭上的吸附得出,活性炭微孔结构对SiW_(12)在其表面的吸附起着分子筛作用。水溶剂化的SiW_(12)分子可顺利进入活性炭1.7nm左右的微孔,而其它溶剂化的SiW_(12)分子,则需较大的孔径。提出了SiW_(12)在活性炭表面吸附的微孔中孔扩散模型。
Resumo:
本文用半经验量子化学方法MNDO研究了由联苯衍生物产生的[C12H8]2+双电荷离子的结构,讨论了其中的电荷定位和影响离子稳定性的因素,双电荷离子的两个电荷分别定位于两个苯环上,表明该离子是由联苯衍生物经两步反应产生。
Resumo:
The title complex was prepared by reacting Yb(NO3)3 (12-crown-4) with 1, 10-phenanthiroline (hereafter phen) in acetone. It crystallized in the triclinic space group P1BAR with a = 10.095(5), b = 17.415(4), c = 8.710(2) angstrom; alpha = 92.45(2), beta = 115.83(3), gamma = 74.08(3)degrees and D(c), = 1.85 g cm-3; Z = 2. The metal ion in this complex is nine-coordinated to three bidentate nitrate ions, two nitrogen atoms of a phen and a water molecule. The crown ligand is hydrogen bonded to the coordination water molecule. The symmetry change of the crown ether is also discussed.
Resumo:
A phosphomolybdic anion doped polypyrrole (PMo12O403- + PPy) film electrode has been prepared by electrochemical polymerization of pyrrole in an aqueous solution of 0.5 mol l-1 H2SO4 or 0.5 mol l-1 KNO3 containing PMo12O403- anions, and characterized by scanning electron microscopy and in-situ UV-visible spectroelectrochemical methods. The film electrode obtained is very stable upon potential cycling in acidic solution, but not in neutral solution. The catalytic effect of the film electrode on the reduction of ClO3- and BrO3- was studied.
Resumo:
The title complex was synthesized and characterized by H-1, C-13, Sn-119 NMR and IR spectra. A single crystal X-ray diffraction study confirmed its molecular structure and revealed that 3,4,5-trimethoxy-benzoyl salicylahydrazone was a tridentate and approximately planar ligand. The complex crystallizes in the triclinic space group P1BAR with a = 9.208(3), b = 12.536(2), c = 12.187(4) angstrom, alpha = 113.12(2), beta = 90.58(2), gamma = 81.42(2), V = 1277.5(6) angstrom, Z = 2. The structure was refined to R = 0.033 and R(w) = 0.041 for 3944 observed independent reflections. The tin atom has a distorted trigonal bipyramidal coordination. The Sn-C bond lengths are 2.129(5) and 2.113(5) angstrom (av. 2.121(5) angstrom), the C-Sn-C angle is 123.3(2); the bond length between the tin atom and the chelating nitrogen is 2.173(3) angstrom. Two chain carbon atoms and the chelating nitrogen atom occupy the basal plane. The skeleton of two erect oxygen atoms and the tin atom is bent (O-Sn-O angle = 153.5(1)). In the complex, the ligand exists in the enol-form.
Resumo:
使用溶胶-凝胶法制备了平均粒径为20~150nm的Y_3Al_5O_(12)超微粉末。从凝胶至超微粉末的过程中,发生了较大的失重现象。纯相晶态的Y_3Al_5O_(12)超微粉末的最低生成温度为900℃。粉末平均粒径随着灼烧时间的增加而逐渐增大,随着灼烧温度的增加而显著增大。
Resumo:
用蒸发溶液法从磷酸溶液中培养出两种形态的 KHoP_4O_(12)单晶,晶体结构测定表明是两种不同结构,即α型和β型。用 X 光衍射、显微镜、红外光谱和热分析方法研究了晶体的结构特性,并对结果进行了讨论。
Resumo:
A vitamin B-12 chemically modified electrode (CME) was constructed by adsorption of vitamin B-12 onto a glassy carbon surface. The electrode catalyzes the electrooxidation of hydrazine compounds over a wide pH range. The electrocatalytic behavior of hydrazines is elucidated with respect to the CME preparation conditions, solution pH, operating potential, mobile phase flow rate, and other variables. When applied to liquid chromatographic detection of the analytes, the vitamin B-12 CME yielded a linear response range over 2 orders of magnitude, and detection limits at the picomole level. The vitamin B-12 CME offers acceptable catalytic stability in both batch and flow systems.