A New Saponin Transformed from Ginsenoside Rh1 by Bacillus subtilis

A novel saponin was isolated from the transformed products of ginsenoside Rh1 by Bacillus subtilis. It‘s structure was determined to be 3-O-β-D-glucopyranosyl-6-O-β-D-glucopyranosyl-20 (S)-protopanaxatriol on the basis of the spectral data.     

Oxidative reactivity of S-nitrosoglutathione with Hantzsch 1,4-dihydropyridine

[formula: see text] S-Nitrosoglutathione oxidized 4-substituted Hantzsch 1,4-dihydropyridines in CH3CN/H2O or CH3CN/phosphate aqueous buffer solution to give aromatic products in various yields.     

AlCl_3／SbCl_3复合体系引发α－蒎烯／苯乙烯阳离子共聚合

比较了ＡｌＣｌ_３和ＡｌＣｌ_３／ＳｂＣｌ_３复合体系的α－蒎烯／苯乙烯阳离子共聚反应及产物的摩尔质量分布。结果表明，由于用ＡｌＣｌ_３体系两种单体活性差大而难以共聚，用ＡｌＣｌ_３／ＳｂＣｌ_３复合体系，苯乙烯聚合速率相对减小，而α－蒎烯聚合速率增大，加之苯乙烯的共催化剂作用，加速α－蒎烯聚合，可使α－蒎烯与苯乙烯进行有效共聚。考察了［Ｓｂ］／［Ａｌ］比、催化剂浓度、单体投料比等对共聚体系α－蒎烯、苯乙烯转化速率及产物Ｍ_ｎ的影响。     

Benzylation of Aromatic Compounds with Benzyl Chloride Catalyzed by Nafion/SiO_2 Nanocomposite Catalyst

Diphenylmethane and substituted diphenylmethane are important compounds forsynthesis chemistry as well as industrial chemistry. These compounds are easilysynthesized by the benzylation of aromatic compounds with benzyl chloride or benzylalcohol catalyzed by homogeneous acid catalysts, such as AlCl3, FeCl3, H2SO4, HF andBF3. However, these catalytic systems are highly corrosive, and usually proceed withlow selectivity. In addition, they are less satisfactory from the environmen…     

壳聚糖及其衍生物在分析化学中的应用

介绍了壳聚糖及其衍生物在分离富集、色谱固定相、电化学分析和生物传感器等方面的应用研究进展，并展望了其在分析化学中的应用前景。     

The reaction of fluorine-containing compounds with conjugated dienoic acids initiated by sodium dithionite

The reaction of fluorine-containing halides and acetamides with conjugated dienoic acids initiated by sodium dithionite gave halide-free 1,4-adducts in 40-80% yields, with the E configuration as the major products.     

流动注射-速差动力学分析研究 meso-四-(4-三甲铵基苯)卟啉光度法测定痕量铅

本文研究了多种金属离子与meso-四-(4-三甲铵基苯)卟啉的显色反应动力学特性。利用Pb(Ⅱ)和其它金属离子之间的反应速差,建立了一种选择性好的测定痕量Pb(Ⅱ)的流动注射分析法。将此法应用于陶瓷和人发样品中铅的直接测定,结果满意。     

MORPHOLOGY OF A THERMOTROPIC AROMATIC POLYESTER

The crystalline morphology of a thermotropic aromatic polyester has been studied by microscopy techniques. Spherulites with ringed structure under polarizing micioscope were observed for solution cast specimens, They were composed of radially growing crystalline lamellae of thickness around 100. It was found that the molecules were packed in the thickness direction. Banded texture was observed in randomly packed domains for melt cast specimens. The bands have the same width and internal structure as those usually observed in oriented specimens of these polymers obtained by shearing their mesomorphic melt.     

多核NMR在相图研究中的应用——Na2SO4-Al2(SO4)3-H2O体系的23Na、27Al NMR研究

In the present paper, Na_2SO_4-Al_2(SO_4)_3-H_2O system has been studied by ~(23)Na and ~(27)Al NMR quantitative method. It has been shown that the existence of double salt can be easily identified by this method.     

色素类胆结石难溶原因的分析

本文采用不同的溶剂对溶解前后的胆色素类结石进行了主要元素的控制，同时对特征色素类结石进行了有机元素分析，通过比较溶解前后超微结构和各种元素含量的变化，认为胆红素与金属离子，尤其是钙及其后二阶金属离子，形成了胆色素盐或配位络合物，并与糖蛋白等螯合成了大分子复合物。这是胆色素类结石难溶的主要原因。