衍生荧光法测定盐酸西布曲明

通过衍生反应，建立了用荧光光度法测定盐酸西布曲明的新方法。并对衍生体系、反应条件、产物稳定性等进行了研究。实验确定丙二酸和乙酸酐混合试剂与盐酸西布曲明在75℃的水浴中加热15min，所得产物发射强荧光，最大激发波长λcx=456nm，最大发射波长λem=496nm。在上述波长下，荧光强度与盐酸西布曲明的质量浓度在0．11～9．5μg／mL范围内呈良好的线性关系，检出限为13．4ng／mL，标准加入回收率在95．4％～104．2％。用于曲美胶囊中盐酸西布曲明的测定。     

Synthesis and structure of a new tetranuclear macrocyclic antimony(v) complex

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SYNTHESIS OF CONDUCTIVE POLYANILINE VIA OXIDATION BY MnO2

A unique process of chemical oxidation polymerization of aniline using manganese dioxide (MnO2) as the oxidizing agent in an aqueous medium is described. The reaction between aniline and MnO2 follows a mechanism by which the organic monomer is oxidized while the metal oxide undergoes reductive dissolution. The effects of the amount of oxidizing agent and aniline, pH and temperature of the reactive system, type of acid on the yield and conductivity of polyaniline are discussed. The resulting polyaniline was characterized by [R and UV-Vis spectrometry. Polyaniline with a conductivity of 12.5 S/cm was obtained using 0.033 tool of aniline oxidized by 0.023 tool MnO2 in the presence of 100 mL of 2.7 mol/L HCI at 25℃ for 4 h.     

NMR spectra of salicylohydroxamic acid in DMSO-d6 solution: a DFT study

The ¹H, ¹³C and ¹H, ¹³C COSY NMR spectra of salicylohydroxamic acid (sha) were measured in DMSO-d₆ solution. The B3LYP GIAO method with the 6-311++G(d,p) basis set was chosen to reproduce the experimental spectra. All possible zusammen and entgegen conformers of monomeric sha were computed. After geometry optimisation (B3LYP/6-311++G(d,p)) only nine independent models of the molecule were shown to be stable. Additionally, the NMR chemical shifts of the Onsager model of the most stable monomer were calculated. The computed chemical shifts for the labile protons for all aforementioned geometries meaningfully underestimated experimental results suggesting the existence of the H-bonded structure of sha in DMSO solution. The most probable two dimeric structures along with two solvent-bounded aggregates were subsequently calculated at the same level of theory. The best agreement was obtained for sha H-bonded with two DMSO molecules (confirmed by the absence of concentration effect). The relative error not exceeding 10 and 4% for chemical shifts in ¹H and ¹³C NMR spectra of sha–(DMSO)₂, respectively, showed that the applied method with the B3LYP/6-311++G(d,p) basis set was efficient to predict the NMR shifts of a compound with strong H-bonds. Thus, this allows to assign properly NMR resonances to specific structure formed in DMSO solution.     

Conversion of sodium lactate to lactic acid with water-splitting electrodialysis

The conversion of sodium lactate to lactic acid with water-splitting electrodialysis was investigated. One way of reducing the power consumption is to add a conductive layer to the acid compartment. Doing this reduced the power consumption by almost 50% in a two-compartment cell, whereas the electric current efficiency was not affected at all. Three different solutions were treated in the electrodialysis unit: a model solution with 70 g/L of sodium lactate and a fermentation broth that had been prefiltered two different ways. The fermentation broth was either filtered in an open ultrafiltration membrane (cut-off of 100,000 Dalton) in order to remove the microorganisms or first filtered in the open ultrafiltration membrane and then in an ultrafiltration membrane with a cut-off of 2000 Dalton to remove most of the proteins. The concentration of sodium lactate in the fermentation broth was 70 g/L, as well. Organic molecules present in the broth (peptides and similar organic material) fouled the membranes and, therefore, increased power consumption. Power consumption increased more when permeate from the more open ultrafiltration membrane was treated in the electrodialysis unit than when permeate from the membrane with the lower cut-off was treated, since there was a higher amount of foulants in the former permeate. However, the electrodialysis membranes could be cleaned efficiently with a 0.1 M sodium hydroxide solution.     

Stereocontrol in radical polymerization

The stereospecific radical polymerization of vinyl esters, methacrylates, and alpha-substituted acrylates was studied. Fluoroalcohols, as a solvent, have remarkable effects on the stereoregularity of the radical polymerizations of vinyl acetate, vinyl pivalate, and vinyl benzoate, affording polymers rich in syndiotacticity, heterotacticity, and isotacticity, respectively. This method was successfully applied to the polymerization of methacrylates to give syndiotactic polymers. The steric repulsion between the entering monomer and the chain-end monomeric unit bound by the solvent through hydrogen bonding is important for the stereochemical control in these systems. Lewis acid catalysts, such as lanthanide trifluoromethanesulfonates and zinc salts, were also effective for the stereocontrol during the radical polymerization of methyl methacrylate, to reduce the syndiotacticity and alpha-(alkoxymethyl)acrylates to synthesize isotactic and syndiotactic polymers. Radical polymerization of the methacrylates bearing a bulky ester group, such as the triphenylmethyl methacrylate derivatives, gave highly isotactic polymers, as in the case of anionic polymerization. In addition, the control of one-handed helical conformation was attained in the radical polymerization of 1-phenyldibenzosuberyl methacrylate using chiral neomenthanethiol or cobalt(II) complexes as an additive.     

PtCl^2^—6接着PVP修饰电极及其对Fe^2^＋的催化氧化

研究了ＰｔＣｌ＾２＾－６接着ＰＶＰ修饰电极及其催化动力学，用循环伏安法考察了电极的电化学性质，结果表明在酸性溶液中对Ｆｅ＾２＾＋的氧化有显著的催化作用。采用旋转圆盘电极法，极化曲线法等就电极对Ｆｅ＾２＾＋氧化催化过程的控制步骤及有关动力学参数进行了测定。     

Triterpene glycosides from Kalopanax septemlobum. VII. Minor glycosides from stems of Kalopanax septemlobum var. maximowiczii and Kalopanax septemlobum var. typicum

Sixteen triterpene glycosides, three of which were new, hederagenin 28-O-β-D-glucuronopyranosyl ester and 28-O-β-D-gentiobiosyl ester and oleanolic acid 3-O-α-L-arabinopyranoside, were isolated from stem bark of Kalopanax septemlobum. The glycoside contents in stem bark of two varieties, maximowiczii and typicum, were compared. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 49–53, January–February, 2006.     

高效液相色谱检测反－2－苯基－邻－硝基肉桂酸

初探了反－２－苯基－邻－硝基肉桂酸（ＰＮＣＡ）的高效液相色谱分离，优选出了最佳分离条件。所建立的方法简单、快速，适用于工业生产中的控制及分析。     

杉木针叶磷脂酰甘油脂肪酸组成分析

用改进的DEAE阴离子交换柱色谱法和硅胶薄层色谱法分离制备杉木针叶磷脂酸甘油，用气相色谱法测定了它的脂肪酸组成。分析结果表明，抗寒性强的杉木品种的针叶磷脂酰甘油脂肪酸的（18:1＋18:2＋18:3）／[16:0＋16:1（3t）]比值比不抗寒品种的高。