流动注射分光光度法测定微量铜的研究

研究了在ＴｒｉｔｏｎＮ－１０１存在下，２－羟基－３－羧基－５－磺酸基苯重氮氨基偶氮苯（ＨＣＳ－ＤＡＡ）显色流动注射光度测定微量铜的新方法，用ｐＨ０．４～１１．５Ｎａ２Ｂ４Ｏ７－ＮａＯＨ缓冲溶液作载流，ＨＣＳＤＡＡ和ＴｒｉｔｏｎＮ－１０１的混合试剂作试剂流，采双道流路，５３０ｎｍ检测反应生成红色配合物，方法线性范围是０．０２４～０．２０μｇ／ｍＬ，检出限为８ｎｇ／ｍＬ，进样频率为１００样次／ｈ，直接     

Ring expansion of 4,4-diethyl-1,2-dithiolane in the reaction with butylacetylene. Involvement of anion and radical intermediates

The action of lithium butyl acetylenide in THF causes 4,4-diethyl-1,2-dithiolane to undergo ring-opening to form 2,2-diethyl-4-thia-5-decyne-1-thiol, which cyclizes to give 2-butyl-6,6-diethyl-5,6-dihydro-1,4-dithiepin by either a homolytic or a nucleophilic mechanism. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 204–206, January, 1997.     

Y2O3:Eu3+纳米线阵列的制备与表征

Y2O3:Eu3+红色荧光粉由于色纯度高、化学性质稳定和量子效率接近100%而广泛用于荧光灯和投影电视等方面.近年来,Y2O3:Eu3+的大量研究工作主要集中于纳米粉末的制备方法及其与体相材料不同的发光特性[1～3].最近,有关Y2O3:Eu3+及其稀土化合物的纳米管、纳米线和纳米带一维材料的制备成为研究热点.Wu Changfeng等[4,5]利用表面活性剂合成了Y2O3 : Eu3+纳米管.激光格位选择激发测试结果表明,Eu3+在纳米管中占据3个不同的格位,其611 nm处的红色发光峰出现了宽化.He Yu等[6]采用水热法及退火处理制备出了Y2O3:Eu3+纳米带,发现Eu3+的发射峰不仅宽化,而且出现了625 nm的新峰.Li Yadong等[7～9]采用水热法制备了稀土氧化物、硫氧化物和氢氧化物等的纳米线和纳米管,并探索了其形成机理,同时发现Y2O3S : yb3+,Er3+具有上转换的性质.     

Homogeneous chemiluminescence system in neutral and near neutral aqueous solution with ClO2 as oxidant and its analytical application

Using ClO₂ as chemiluminescence (CL) oxidant, a novel homogeneous CL system in neutral and near neutral aqueous solution is proposed in this paper. ClO₂ could oxidize sulfite in pH 5.0–8.5 acetate buffer to produce CL emission, and pipemidic acid could sensitize the CL system. The ClO₂–SO₃²⁻–pipemidic acid reaction was used as a model CL system and explored the possibility of highly active and eco-friendly ClO₂ being used as CL oxidant in neutral and near neutral aqueous solution. Combined with flow-injection analysis, the proposed CL system was applied to the automated dissolution testing of pipemidic acid tablet. Compared with the common strong acidic or strong basic CL system, this proposed CL owns its advantages.     

Synthesis and Crystal Structure of a Novel Three-dimensional Cu(II) Compound {[Cu(2,2''-bipy)(C7H4O5S)(H2O)2]·(H2O}n

The title compound, {[Cu(2,2'-bipy)(C7H4O5S)(H2O)2](H2O}n (2,2'-bipy = 2,2'- bipyridine), was synthesized by the hydrothermal reaction of Cu(NO3)2(3H2O, 2,2'-bipyridine and 2-sulphobenzoic acid, and structurally characterized by single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P with a = 9.21(3), b = 10.17(3), c = 10.77(3) (A), α = 77.017(16), β = 89.80(8), γ = 68.46(7)°, V = 911(5) (A)3, Z = 2, (D/s)max = 0.001, Mr = 473.94, Dc = 1.728 g/cm3, μ(MoKα) = 1.365 mm-1, F(000) = 486, the final R = 0.0246 and wR = 0.0628 for 3809 observed reflections with I > 2σ(I). The mononuclear crystal structure extends into a two-dimensional net- work via hydrogen-bonding interactions and a three-dimensional framework is further formed by means of π-π stacking interactions.     

赖氨酸修饰壳聚糖磁性超微载体的制备和表征

本文设计并合成了良好水溶性的赖氨酸修饰壳聚糖,并对制备工艺进行了优化.产物通过红外(FTIR)和核磁(1H-NMR)进行了表征,并将其作为壳层材料制备了赖氨酸修饰壳聚糖磁性超微载体.通过光电能谱(XPS)、透射(TEM)、激光粒度仪、X射线衍射(XRD)、磁性能测试(VSM)对载体进行了表征.结果表明,制备的赖氨酸修饰壳聚糖磁性超微载体表面带有大量的氨基(-NH2),粒径分布较为均一(100nm左右),形貌较为规则,并具有良好的超顺磁性,因而该载体具有更加良好的性能.     

Pd_2(dba)_3/BINAP催化合成1,4-双-(4′-苯胺基苯酰基)苯

以Pd2(dba)3/BINAP催化1,4-双-(4′-溴苯酰基)苯和苯胺反应,合成了1,4-双-(4′-苯胺基苯酰基)苯,其结构经UV,1HNMR,13CNMR和元素分析表征。     

LiCoO_2 electrode/electrolyte interface of Li-ion batteries investigated by electrochemical impedance spectroscopy

The storage behavior and the first delithiation of LiCoO2 electrode in 1 mol/L LiPF6-EC:DMC:DEC elec- trolyte were investigated by electrochemical impedance spectroscopy (EIS). It has found that, along with the increase of storage time, the thickness of SEI film increases, and some organic carbonate lithium compounds are formed due to spontaneous reactions occurring between the LiCoO2 electrode and the electrolyte. When electrode potential is changed from 3.8 to 3.95 V, the reversible breakdown of the resistive SEI film occurs, which is attributed to the reversible dissolution of the SEI film component. With the increase of electrode potential, the thickness of SEI film increases rapidly above 4.2 V, due to overcharge reactions. The inductive loop observed in impedance spectra of the LiCoO2 electrode in Li/LiCoO2 cells is attributed to the formation of a Li1-xCoO2/LiCoO2 concentration cell. Moreover, it has been demonstrated that the lithium-ion insertion-deinsertion in LiCoO2 hosts can be well described by both Langmuir and Frumkin insertion isotherms, and the symmetry factor of charge transfer has been evaluated at 0.5.     

Identification of a chemical indicator of the rupture of 1,4-β-glycosidic bonds of cellulose in an oil-impregnated insulating paper system

In this study, headspace gas chromatography/mass spectrometry has been used to assess the volatile by-products generated by the ageing of oil-impregnated paper insulation of power transformers. Sealed-glass ampoules were used to age under oxidative conditions 0.5-g specimens of insulating paper in 9 mL of inhibited mineral oil in a temperature range of 60–120 °C and moisture of 0.5, 1 and 2% (w/w). A linear relationship between one of the oil-soluble degradation by-products, i.e. methanol, and the number of ruptured 1,4-β-glycosidic bonds of cellulose, regardless of the type of paper (ordinary Kraft or thermally-upgraded (TU) Kraft paper), was established for the first time in this field. Ageing at 130 °C of model compounds of the Kraft paper constituents (α-cellulose, hemicellulose and lignin) and two cellulosic breakdown by-products (D-(+)-glucose and 1,6-anhydro-β-d-glucopyranose) confirmed that the α-cellulose degradation was mostly responsible for the presence of this molecule in the system. Furthermore, additional 130 °C-tests with six different papers and pressboard samples under a tight control of initial moisture indicated that at least one molecule of methanol is formed for each rupture of 1,4-β-glucosidic bond of the molecular chains. Stability tests showed that the ageing indicator is stable under the oxygen and temperature conditions of open-breathing transformers. The presence of methanol was detected in 94% of oil samples collected from over than 900 in-service pieces of equipment, confirming the potential for this application. Lastly, the tests have shown that oil-oxidation by-products and TU-nitrogenous agents modify the methanol partitioning coefficients in the paper/oil/air system, which makes their study essential over a range of field conditions encountered by power transformers. Results are presented and discussed in comparison with 2-furfuraldehyde, which is the current reference in the domain.     

手性钯络合物催化下2-硝基环酮的不对称烯丙基化反应

在用氮杂冠醚改良的手性二茂铁膦与钯的络合物催化下, 2-硝基环酮可进行不对称烯丙基化反应. 讨论了配位基的形状, 反应物的构造, 碱的类型以及反应时间对反应速率和立体选择性的影响. 通过增加反应的空间位阻改进了反应的立体选择性 .