Surface functionalization of polymer latex particles. II. Catalytic oxidation of poly(methylstyrene) latexes in the presence of cetyltrimethylammonium bromide

Surface-functionalized cationic poly(methylstyrene) (PMS) latex particles containing aldehyde and carboxylic acid groups were successfully achieved via an emulsion polymerization of 3(4)-methylstyrene in the presence of cetyltrimethylammonium bromide, followed by an in-situ oxidation catalyzed by copper chloride and tert-butyl hydroperoxide (t-BuOOH). Factors such as the type of metal catalyst, oxidant, and their concentration strongly affected the rate of oxidation. Step addition of t-BuOOH resulted in both a higher degree of oxidation and a more uniform distribution of particle size of the functionalized PMS as compared to the batch addition method. The effect of organic solvent was found to be insignificant, and the oxidation could still proceed in its absence. The particle sizes increased significantly during the oxidation but could be controlled by using crosslinked PMS latexes. Finally, the versatility of this oxidation process was demonstrated by oxidation of the polymer with a solid loading as high as 28%. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3585–3593, 1997     

Crystal structure and ionic conductivity of the soft solid crystal: isoquinoline<Subscript>3</Subscript>•(LiCl)<Subscript>2</Subscript>

A soft solid crystal composed of isoquinoline (IQ) and LiCl was prepared based on the concept of Pearson’s hard-soft acid-base (HSAB) theory. Single-crystal X-ray diffraction best described the isoquinoline₃?(LiCl)₂ as consisting of molecular Li₄Cl₄(isoquinoline)₆ units, where the LiCl cluster is an array of edge-fused Li₂Cl₂ rhombs. Electrochemical impedance measurements on pressed pellets showed that conductivity occurs mainly through the bulk via a hopping mechanism, with a calculated activation energy of E_a = 67 kJ/mol. The high value of the activation energy was due to Li₄Cl₄ clusters that were well separated by intervening IQ ligands in the crystal structure, requiring large hops for ions to migrate through the lattice.     

ICP－AES法测定栽培灵芝中9种微量元素

本文报导了采用美国ＬｅｅｍａｎＬａｂｓ公司生产的ＰＳ－Ⅰ型中阶梯光栅光谱仪，对栽培灵芝中Ｇｅ、Ｃａ、Ｍｇ、Ｚｎ、Ｃｕ、Ｍｎ、Ｆｅ、Ｋ、Ｎａ等元素进行了测定。为防止Ｇｅ的挥发损失，采用了ＨＮＯ３－ＨＣｌＯ４低温湿法消化的前处理方法。相对标准偏差为１．３１％－９．１１％，回收率为９１．０％－１１０．０％，结果令人满意。     

Constituents of Ilex Species I. On the Leaves of Ilex Cornuta Lindl

Phytochemical examination on the leaves of Ilex cornuta Lindl. (Aquifoliaceae) resulted in the isolation and identification of lupeol (I), 3β-hydroxylup-20(29)-en-30-al (II), oleanolic acid (III), and β-sitosterol-β-D-glucoside (IV).