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971.
目的对气相色谱-质谱联用仪法测定橡胶制品中多环芳烃(蒽)含量不确定度进行评定,确定影响不确定度的关键因素。方法依据《ZEK01.4-2008 GS认证过程中PAHs的测试和验证》,使用气相色谱-质谱联用仪法测定橡胶制品中多环芳烃(蒽)含量,并对结果的不确定度进行评定,分析影响测量不确定度的各个因素,对各个分量进行计算和合成。结果扩展不确定度U=5.7 mg/kg,置信概率95%。结论该实验的不确定度主要影响因素是曲线校准。  相似文献   
972.
发展了种基于汞离子(Hg2+)适配体(Aptamer)免标记金纳米粒子的动态光散射(DLS)法,用于灵敏、选择性的检测溶液中的Hg2+。Aptamer 5’-TTTCTTCTTTCTTCCCCCCTTGTTTGTTGTTT-3’与Hg2+的特异性结合使金纳米粒子失去保护,在含有100 mmol/L NaCl的缓冲溶液中发生聚集,金纳米粒子的平均水合粒径变大。在pH=7.43,110 nmol/L Aptamer,100 mmol/L NaCl,Hg2+与Probe DNA孵育时间为30 min的实验条件下,金纳米粒子水合粒径的变化值("D)与Hg2+的浓度成正比。检出Hg2+的线性范围为0.1 nmol/L~5μmol/L,检出限达0.1 nmol/L。湖水及矿泉水两种水样加标实验表明本方法能够用于实际水样中Hg2+的检测。  相似文献   
973.
An facile and efficient protocol for the synthesis of 13‐aryl‐indeno[1,2‐b]naphtha[1,2‐e]pyran‐ 12(13H)‐ ones has been developed that proceeds via the one‐pot three‐component sequential reaction of an aromatic aldehyde with β‐naphthol and 2H‐indene‐1,3‐dione under solvent‐free conditions in the presence of a poly(4‐vinylpyridinium)hydrogen sulfate(P(4‐VPH)HSO4) catalyst. The catalyst can be reused several times, making this procedure facile, practical, and sustainable. The simple experimental procedure, solvent‐free reaction conditions, use of an inexpensive catalyst, short react time, and excellent yields are some of the major advantages of this methodology.  相似文献   
974.
将手性二茂铁双膦配体ImiFerroPhos应用到β-取代-α,β-不饱和磷酸酯的不对称氢化反应中,在温和的反应条件下,以高收率及较高对映选择性合成了一系列β-取代的手性磷酸酯,最高获得了92%的ee值.  相似文献   
975.
李欢欢  刘利  明春伦  崔广华 《结构化学》2014,33(7):1050-1056
A new Cd(Ⅱ) coordination polymer, {[Cd(Hnbta)(L)]·H2O}n(L = 1,4-bis(5,6-dimethylbenzimidazol-1-yl)butane), H3nbta= 5-nitrobenzene-1,2,3-tricarboxylic acid), has been hydro-thermally synthesized and characterized by elemental analyses, IR, XRPD, and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group P21/n with a = 17.3056(13), b = 11.0114(9), c = 17.7484(14) A, β = 117.3640(10)o, V = 3003.7(4) A3, Z = 4, C31H31CdN5O9, Mr = 730.01, Dc = 1.614 g/cm3, μ = 0.792 mm-1 and F(000) = 1488. The cadmium(Ⅱ) ions are bridged by Hnbta2- to generate a two-dimensional metal organic framework with fes topology. In addition, the thermal stability and fluorescence properties of the complex were also studied.  相似文献   
976.
滕腾  陈进  陈旭林  余荣民  卢灿忠 《结构化学》2014,33(11):1661-1665
A three-coordinate Ag(I) complex, [Ag(Mepzpy)(PAr3)]BF4·H2O(1, Mepzpy = 3-methyl-1-(2-pyridyl)pyrazole, PAr3 = tri(o-tolyl)phosphine), was synthesized from the reaction of Ag(CH3CN)4BF4, PAr3 and Mepzpy in CH3 CN at room temperature. The compound was characterized by UV-vis, NMR and X-ray single-crystal structure analysis. It crystallizes in triclinic space group P1 with a = 10.2251(5), b = 10.6014(5), c = 15.7012(5) , α = 92.963(3), β = 92.641(3), γ = 114.647(4)o, V = 1540.6(1) 3, Z = 2, Mr = 676.24, Dc = 1.458 g/cm3, F(000) = 688, μ = 6.187 mm-1, GOOF = 1.038, the final R = 0.0530 and w R = 0.1493 for 6371 observed reflections with I 2σ(I). Compound 1 is ionic. It is composed of a BF4- anion and a [Ag(Mepzpy)(PAr3)]+ cation. The Ag(I) ion adopts a distorted trigonal pyramidal coordination geometry defined by two nitrogen atoms and a phosphorous atom. The complex emits blue luminescence with maximum peaks at 470 nm in solid state at room temperature.  相似文献   
977.
The effect of nanoclay on the phase-separation behavior of poly(methyl methacrylate)/poly(vinyl acetate)(PMMA/PVAc) blends has been mainly investigated by small-angle laser light scattering. It is found that the effect of clay on the thermodynamics and kinetics of phase-separation for PMMA/PVAc blends seems inconsistent. The kinetics phaseseparation rate decreases, while the thermodynamics parameters, cloud points Tc and delay time tD of isothermal phaseseparation also decrease, and the variation amplitude depends on the matrix composition. The affinity of clay to PMMA results in the composition difference between the border layer and the polymer matrix and further causes the concentration fluctuation at the early stage of phase separation to reduce Tc and tD. On the other hand, the decrease of phase-separation rate is caused by the mechanical barrier effect of clay on the macromolecular diffusion of blend matrix. Hence, such seemingly counterintuitive results on the thermodynamics and kinetics of phase-separation are attributed to different dominant factors.  相似文献   
978.
范宏 《高分子科学》2014,32(7):854-863
This contribution reports ethylene polymerization behavior of titanium complexes incorporating bis(phenoxyimine) ligands. Six phenoxy-imine Ti(IV) complexes {6-R1-2-[CH=N(2,6-difluoro-3,5-diR2-4-R3Ph)]C6H3O}2TiCl2(1: R1 = H, R2 = H, R3 = H; 2: R1 = H, R2 = H, R3 = 4-vinylphenyl; 3: R1 = CH3, R2 = H, R3 = H; 4: R1 = CH3, R2 = H, R3 = 4-vinylphenyl; 5: R1 = CH3, R2 = F, R3 = H; 6: R1 = CH3, R2 = F, R3 = 4-vinylphenyl) have been synthesized and evaluated for ethylene polymerization using dried MAO(simplified as DMAO) as cocatalyst. An obvious catalytic heterogeneity of Cat 2(Complex 2/DMAO) towards ethylene polymerization was observed, which was illustrated by decreased activity, multimodal molecular weight distribution and partially improved particle morphology comparing with Cat 1. Moreover, Cat 3 exhibits "living" characteristics in the process under certain conditions(25 °C, less than 20 min). Otherwise, the moderate to high ethylene polymerization activity of ca. 105-106 g PE/(mol Ti·h) and high molecular weight(Mw = 105-106) of polyethylene can be obtained by changing the skeleton structure of these complexes.  相似文献   
979.
宋志国  孙啸虎  杨喜宝 《化学通报》2014,77(10):990-993
无溶剂条件下,硫酸氢钾可有效催化芳香醛、苯乙酮衍生物和脲的三组分"一锅法"Biginelli反应来合成5-未取代的3,4-二氢嘧啶-2(1H)-酮。确定了优化反应条件。产品结构经IR、1H NMR、MS和元素分析进行表征。  相似文献   
980.
以氯乙酰氯、N-乙基对碘苯胺为原料,经酰化反应合成了N-乙基-N-(4-碘苯基)氯乙酰胺,接着与1-甲基咪唑反应,随后在水溶液中和四氟硼酸钠发生阴离子交换,合成了四氟硼酸1-甲基-3-(N-乙基-4-碘苯氨基甲酰甲基)咪唑鎓盐,该四氟硼酸盐在过氧化氢/三氟乙酸酐体系中氧化得到一种新的离子负载的双(三氟乙酰氧基)碘苯试剂四氟硼酸(1-甲基-3-{N-乙基-4-[双(三氟乙酰氧基)碘]苯氨基甲酰甲基}咪唑鎓盐)。所合成的碘苯试剂没有吸湿性,在空气中长期放置不变质。以这种新试剂为氧化剂,室温下乙酰苯胺及其衍生物与乙酸区域选择性地发生乙酰氧基化反应,产率较高。该离子负载型碘苯试剂可回收后再生,而再生试剂用于乙酰氧基化反应时活性几乎保持不变。  相似文献   
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