双功能催化剂体系作用下乙烯二聚和共聚合的研究

用乙烯为原料在双功能催化剂体系的作用下通过二聚和共聚合反应，直接合成线性低密度聚乙烯（ＬＬＤＰＥ）．所用二聚反应催化剂为钛酸正丁酯（Ｔｉ（ＯＢｕ）_４），共聚催化剂为ＴｉＣｌ_４／ＭｇＣｌ_２（ＺＭ－１催化剂）．研究了二聚反应动力学行为及影响双功能催化剂体系动力学过程的一些因素．结果表明利用这两种催化剂组成双功能催化剂体系能够很方便地制得密度范围在０．９０－０．９３，Ｅｔ／１０００Ｃ在１０－４０的ＬＬＤＰＥ．     

2,3,5-三溴-4''''-硝基-4,2''''-双羟基二苯醚的合成及其抑菌活性研究

天然多溴代羟基二苯醚类化合物是存在于海洋海绵体中的一类抑菌活性物质,国内外学者对此类物质进行了大量的研究工作,发现他们具有良好的抑菌性,能有效抑制多种有害菌[1-4]的生长.     

High-throughput purification of combinatorial libraries I: a high-throughput purification system using an accelerated retention window approach

We have developed a high-throughput purification system to purify combinatorial libraries at a 50-100-mg scale with a throughput of 250 samples/instrument/day. We applied an accelerated retention window method to shorten the purification time and targeted one fraction per injection to simplify data tracking, lower QC workload, and simplify the postpurification processing. First, we determined the accurate retention time and peak height for all compounds using an eight-channel parallel LC/UV/MS system, and calculated the specific preparative HPLC conditions for individual compounds. The preparative HPLC conditions include the compound-specific gradient segment for individual compounds with a fixed gradient slope and the compound-specific UV or ELSD threshold for triggering a fraction collection device. A unique solvent composition or solvent strength was programmed for each compound in the preparative HPLC in order to elute all compounds at the same target time. Considering the possible deviation of the predicted retention time, a 1-min window around the target time was set to collect peaks above a threshold based on UV or ELSD detection. Dual column preparative instruments were used to maximize throughput. We have purified more than 500 000 druglike compounds using this system in the past 3 years. We report various components of this high-throughput purification system and some of our purification results.     

在PVA存在下Os-SnCl_2-亮绿离子缔合体系的研究高纯镍中微量Os的测定

本文研究了Os-SnCl_2-PVA-亮绿离子缔合体系的显色反应,摩尔吸光系数ε_(434)为5.6×10~6L·mol~(-1)·cm~(-1),锇含量在0.1～0.7μg/25mL范围内遵守比耳定律,室温下显色后,吸光度在110min内稳定。研究了30种外来离子的影响,并进行了高纯镍中微量锇的测定。     

Microstructure and Ion Exchange in Stearic Acid Langmuir-Blodgett Films Studied by Fourier Transform Infrared-Attenuated Total Reflection Spectroscopy

Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectra have been recorded of 11-layer Langmuir-Blodgett (LB) films of stearic acid deposited at various surface pressures (0.1, 15, and 35 mN/m), and the molecular orientation angles were evaluated quantitatively, which supplied insight into the molecular order with the alkyl chains tightly packed like crystal in the LB films deposited at the zero and higher surface pressures. These experimental results indicate that, in the Langmuir film as the precursor of LB films, stearic acid molecules self-aggregate to form two-dimensional crystalline domains already even at the zero surface pressure, which results in the inhomogeneity of monolayer. The analysis of dependence of nu(C=O) intensity on the surface pressure, surface density, and subphase temperature leads to the conclusion that the defects in LB films originate from the Langmuir film and be conserved upon deposition. Annealing below 50 degrees C and cooling could improve the monolayer homogeneity, and thus a defect-free or low-defect LB films can be deposited. Furthermore, ion exchange conducted in the LB films, on the other hand, confirms the existence of structure defects in LB films of stearic acid. The polar plane microstructure, lateral transport along the polar planes and the coordination types of stearic acid/cation system may be the rate-limiting process. The results have implication on the possible uses of stearic acid LB films as ion-exchange materials or sensors. Copyright 2001 Academic Press.     

Determination of Gossypol in Trace Level by Flow Injection Analysis with Chemiluminescence Detection

Gossypol, [1, 1′, 6, 6′, 7,7′-hexahydroxyl-5,5′-diisopropyl-3,3′-dimethyl-(2,2′-binaphtha- lene)-8,8′-dicarboxaldehyde] is a polyphenolic yellow compound naturally occurring in various parts of cotton plants1. The compound has been associated with     

A New Method to Synthesize the P,N-Heteromultifunctional Ligands

The nature of the highly polar P-N bond in phosphinimine makes a ligand of this kind become versatile in both coordination and organometallic chemistry.[1,2] Usually this kind of phosphinimine phosphine P,N-heterodifunctional ligands is prepared by the Staudinger reaction of azides with organophophine. Now a more mild and efficient method is provided. The product of Mannich reaction of 2-aminopyridine reacted with Ph2PCl in the presence of Et3N, giving the phosphinimine compound 1 in more than 90% yield.     

PPC/SBR并用弹性体的配方选择

利用正交法对丁苯橡胶（SBR）／聚丙撑碳酸酯（PPC）共混弹性体进行配方设计，得到了一个具有良好综合性能的配方。并通过方差分析得出PPC含量和马来酸酐（MA）用量是影响弹性体拉伸性能的最显著因素。     

活性炭和石墨混合载体的Pt催化剂（Pt/CG）对乙醇氧化电催化活性的影响

用化学沉积法制备炭载Pt(Pt/C)和以活性炭与石墨作混合载体的Pt(Pt/CG)催化剂。实验结果表明，活性炭与石墨质量比影响Pt/CG催化剂对乙醇氧化的电催化活性。当活性炭与石墨的质量比为15∶1时，制得的Pt/CG催化剂对乙醇氧化的电催化活性最高。