Determination of the diastereomers of vitamin K1

A method is described for the gas-chromatographic determination of the diastereomers of vitamin K₁ (phylloquinone) in the form of their dihydro dimethyl ethers. The reported method of derivatization and chromatographic analysis in conjunction with optical rotation measurements are useful approaches for characterization of vitamin K₁ samples with respect to their origin.     

有机硅侧链液晶研究进展

综述了国内外有机硅侧链液晶近年来的研究进展，对近晶型、席夫碱型、向列型、胆甾型、偶氮苯型、鱼骨型以及光学非线性型几种主要类型的有机硅侧链液晶进行了详细介绍，并对近年来受到重视的有机硅侧链液晶电流性和离聚物研究进展作了较全面的总结，最后对其应用前景进行了展望。     

一类新的毛细管气相色谱固定液—侧链液晶冠醚聚硅氧烷的研究

合成了一种新的毛细管气相色谱用固定液——侧链含冠醚液晶的聚硅氧烷,这种固定液易于涂渍在弹性石英毛细管柱上,柱效高,热稳定性好,极性中等,它具有高分子液晶和高分子冠醚固定液的双重保留性能,适于分离多种异构体。     

Bioanalytical methods applied to endocrine disrupting polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. A review

The usual methods for determining polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) are generally expensive and time consuming. This fact has favored the development of faster and cheaper techniques, based on immunoassays and bioassays. This paper reviews these bioanalytical methods and their analytical importance at the present moment.     

A new catalyst for direct synthesis of dimethyl ether from synthesis gas

A new catalyst has been prepared by coprecipitation sedimentation method developed in our laboratory. It exhibits excellent catalytic activity, selectivity and stability for conversion of synthesis gas to dimethyl ether: conversion of CO 92%, selectivity of dimethyl ether 98%. Catalytic properties of the catalyst show no evident change after being used for 100 h.     

Glass capillary gas chromatography of amino acid enantiomers

Glass capillaries coated with Chirasil-Val, a chirally functionalised polysiloxane, are capable in principle of resolving all protein amino-acid enantiomers in a single run and within a short analysis time, thus allowing for example the quantitative amino acid determination by enantiomer labelling. The elution characteristics of the individual amino acids however are also dependent upon the chemical nature of the capillary wall surface, and a surface pretreatment is found to be necessary if all protein amino acids are to be analysed. Of the various methods of pretreatment tested, etching of borosilicate glass with gaseous HCl followed by deposition of colloidal silicic acid is considered to be the most suitable.     

乙烯基聚硅氧烷共聚反应竞聚率的测定及其对复合粒子形态的影响

用Ｆｉｍｅｍａｎ－Ｒｏｓｓ法处理数据，测定了乙烯基聚硅氧烷（ＳＶ）与苯乙烯（ＳＴ）、甲基丙烯酸甲酯（ＭＭＡ）和甲基丙烯酸正丁酯（ｎ－ＢＭＡ）的共聚反应的竞聚率，结果为ｒＳＴ＝１．４５和ｒＳＶ＝１．０８，ｒＭＭＡ＝０．７８和ｒＳＶ＝２．０１，ｒｎ－ＢＭＡ＝０．４６和ｒＳＶ＝３．４９．以含ＳＶ的乳液作为种子进行烯类单体的乳液聚合，单体和ＳＶ共聚反应对复合粒子的形态有很大影响。     

镉化合物的~(113)Cd屏蔽张量2-氨基二甲基吡啶镉单晶的研究

2-氨基二甲基吡啶镉的单晶已被单晶定向的~(113)Cd核磁共振进行了研究。在CdCl_2+2-氨基二甲基吡啶中对于两个氯-四个氮的~(113)Cd的屏蔽张量元素分别是σ_(33)=368,σ_(22)=266,和σ_(11)=236×10~(-6)。     

紫外光固化聚二甲基硅氧烷脲撑氨基甲酸甲基丙烯酸酯的研究——Ⅱ亲水疏水共聚网络体系

本文以α、ω-二氨丙基封端的聚二甲基硅氧烷、甲苯二异氰酸酯、甲基两烯酸羟乙酯为原料,合成了甲基丙烯酸酯封端的聚二甲基硅氧烷聚氨酯。并以此作为反应性低聚物,以甲基丙烯酸羟乙酯为亲水性反应稀释剂,通过紫外光固化,合成了一系列聚硅氧烷含量不同的共聚网络。应用红外光谱、凝胶含量测定、热分析、动态力学性能、吸水性实验等方法,对它们的固化程度、亲水疏水性能进行了研究。结果表明:体系中存在着两相结构,增加稀释剂的含量,材料的吸水性增加。通过调节疏水性的聚二甲基硅氧烷和亲水性的甲基丙烯酸羟乙酯的含量可改变体系的亲水疏水平衡。     

碳酸二甲酯法合成1，5-二氨基甲酸甲酯的反应机理

应用红外光谱技术研究了在乙酸锌催化作用下1，5-萘二胺与碳酸二甲酯甲氧基羰基化反应机理．结果表明，二水合乙酸锌只有失去两个结晶水变成无水乙酸锌后才能产生催化活性．无水乙酸锌与1，5-萘二胺形成一个新的配位络合物，该配位络合物是一个适宜的亲核试剂，能与碳酸二甲酯进行亲核反应，生成1，5-萘二胺的甲氧基羰基化产物．在无水乙酸锌与1，5-萘二胺形成配位络合物的过程中，无水乙酸锌的结构从双齿型转变成单齿型．