Asymmetric Synthesis of α-Substituted-γ-butyrolactone Empolying Prolinol Type of Auxiliaries

Eleven (S)-(-)-bishydrocarbyl-(l-alkanoylpyrrolidin-2_yl)_methanol derivatives of three types were synthesized from L-proline.asymmtncally selective alkylation products were obtained oy LDA treatment and alkylation using methyl 2-bromoethyl ether, and three types of chiral α-Substituted-γ-butyrolactones were obtained by hydrolyzing the alkylation products, with %e.e. beijing up to 89 percent.     

10°锥角台锥型液相色谱柱尺寸等比例放大和柱内谱带流型的可视化研究

摘要利用改进的可视化装置, 研究了10°锥角的台锥型液相色谱柱内的谱带流型与柱参数变化的关系. 将有机玻璃柱管加工成内圆台外方型的一体结构, 选择折射率一致的色谱固定相硅胶和流动相环己烷, 使整个色谱柱成为高度清晰的透明体, 能直接观察柱中彩色样品谱带的动态三维流型. 研究结果表明, 在实验条件范围内, 流动相流速对谱带流型无影响, 填料的形状和性质对塞子状流型有一定程度的影响. 比较了柱长为5cm和等比例放大后柱长为10cm锥型柱内的流型, 发现放大后的锥型柱内仍然保持塞子状流型, 总柱效等比例增加. 表明继续按比例放大成为工业规模色谱柱后仍能保持塞子状流型.     

取代苯体系的二阶非线性光学性质:动力学李代数方法

提出了一种动力学李代数方法来研究取代苯体系的非线性光学性质. 对于给定的PPP模型(Pariser-Parr-Pople)哈密顿量, 生成了一个动力学李代数. 依据这些代数元构造出演化算子作为群参数的函数, 通过求解一组非线性微分方程能够得到这些群参数. 再按照统计力学中的密度算子公式给出取代苯分子体系偶极矩的统计平均值. 于是导出二阶极化率的表达式. 与其他量子力学计算结果比较, 表明这种动力学李代数方法在预言有机共轭分子的非线性光学性质上同样有用.     

负载型Au-Pd双金属催化剂的制备及其对CO氧化的催化活性

采用改性的等体积浸渍法制备了SiO2负载的Au-Pd双金属催化剂,考察了催化剂的焙烧温度对CO氧化反应活性的影响.与623,723和773K的条件下焙烧的催化剂相比,673K焙烧的催化剂具有良好的催化CO氧化活性,CO完全转化温度低于398K.应用N2物理吸附、X射线衍射、程序升温还原、CO程序升温脱附及X射线光电子能谱等技术对催化剂进行了表征.结果表明,673K焙烧的催化剂具有最大的比表面积和最小的孔径,存在Au0,Pd0和PdO相,AuxPdy合金相很少;而773K焙烧的催化剂上除了含有Au0,Pd0和PdO相外,还存在明显的AuxPdy合金相.具有大比表面积,小孔径,Au0,Pd0和PdO多相共存的催化剂可使CO的吸附量增加,催化活性提高;而AuxPdy合金相的生成并不能提高催化剂的催化活性.     

Studies on Thermodynamics Features of the Interaction between Imidacloprid and Bovine Serum Albumin

At different temperatures, the interactions between imidacloprid （IMI） and bovine serum albumin （BSA） were investigated with a fluorescence quenching spectrum, a synchronous fluorescence spectrum, a three-dimensional fluorescence spectrum and an ultraviolet-visible spectrum. The average values of bonding constants （KLB： 3.424 × 10^4 L,mol^-1）, thermodynamic parameters （△H： 5.188 kJ,mol^-1, △G^（○—）：-26.36 kJ,mol^-1, △S： 103.9 J,K^-1,mol^-1） and the numbers of bonding sites （n： 1.156） could be obtained through Stern-Volmer, Lineweaver-Burk and ther- modynamic equations. It was shown that the fluorescence of BSA could be quenched for its reactions with IMI to form a certain kind of new compound. The quenching belonged to a static fluorescence quenching, with a non-radiation energy transfer happening within a single molecule. The thermodynamic parameters agree with △H〉 0, △S〉0 and△G^（○-）〈0, suggesting that the binding power between IMI and BSA should be mainly a hydrophobic interaction.     

纳米分辨率的三维形貌检测仪

从光干涉方式，瞳窗关系和光源带宽等基本关系出发，利用空间不变系统理论解析了相移显微干涉检测系统中衍射效应的影响。为了减小横向分辨率对纵向分辨率的影响，利用相关信息提取或数字滤波的方法，获得了纳米分辨率的三维形貌。     

One-Pot Method for Synthesis of Calix[6]biscrowns

p-tert-Butylcalix[6]-1,4-2,5-biscrown-4 is a typical member of the family of calix[6]crowns. In the literature, the compound was synthesized from calix[6]arene by two steps and the overall yield based on calix[6]arene was 24%.Herein we wish to report a one-pot method to do this work. By this method the yield was up to 48% and the reaction time was greatly reduced.     

茉莉醛相转移催化合成法的改良

茉莉醛又称2-戊基肉桂醛,具有优雅的茉莉花香,是一种深受调香师喜爱的合成香料。目前已广泛应用于各种日用化学品中。     

Three-dimensional quantum dynamics study of vibrational predissociation of HeI_2 van der Waals molecule for low vibrational excitation using the time-dependent wave packet method

Three-dimensional quantum mechanical calculations for vibrational predissociation of HeI2(B) van der Waals molecules are presented using the time-dependent wave packet technique within the golden rule approxima tion.The total and partial decay widths,lifetimes,rates and their dependence on initial vibrational states were obtained for HeI2 at low initial vibrational excited levels.Our calculations show that the calculated tota decay widths,lifetimes and rates agree well with those extrapolated from experimental data available The predicted total decay widths as a function of initial vibrational states exhibit highly nonlinear behavior.The very short propagation time (less.than 1 ps) required in the golden rule wave packet calculation is determined by the duration time of the final state inter-action between the fragments on the vibrationally deexcited adiabatic potential surface.The final state interaction between the fragments is shown to play an important role in determining the final rotational distri     

聚甲基丙烯酸甲酯辐射裂解和消旋的空间立构效应

本文研究了三种不同空间立构聚甲基丙烯酸甲酯的辐射效应,提出裂解过程是一种裂解与重合的动态平衡过程。分子量降低和消旋作用对温度的依赖性,是由于分子运动和笼罩效应以及重合的空间位阻效应所致。辐照温度愈高,裂解产额愈大。相同条件下辐照,全同立构比无规立构试样的裂解产额更大。 全同立构聚甲基丙烯酸甲酯辐照后,不仅分子链断裂,而且空间立构也发生很大变化。随着辐照剂量的增加,全同立构含量逐渐减少,而无规立构含量和间同立构含量却逐渐增加。