KF/Al2O3催化合成2-甲基-3-(3,4-亚甲二氧基苯基)丙烯醛

缩合;催化剂;洋茉莉醛;KF/Al2O3催化合成2-甲基-3-(3;4-亚甲二氧基苯基)丙烯醛     

Effects of Heat Treatment on the Crystallization Behavior of Poly(3-alkylthiophenes)

IntroductionPoly( 3- alkylthiophenes) ( P3ATs) ,as a newkind of soluble,fusible and processable conductivepolymers,have attracted a great interest and muchattention ofchemistsand physicists[1,2 ] . Ithas beenwidely accepted that P3ATs can form similarlayered structures with alkyl side chains beingoriented in the lateral a- axis direction[3— 6] .Moreover,when the number of the carbon atoms inthe alkyl side chains is more than1 0 ,some orderlyarrangements of the side chains will occur between…     

A novel general route for the preparation of enantiopure imidazolines

A novel procedure for the preparation of enantiopure 1,4-disubstituted 2-imidazolines is reported. Enantiopure beta-amino alcohols are converted into N-hydroxyethylamides, which are reacted with excess thionyl chloride, or with thionyl chloride followed by phosphorus pentachloride to yield N-chloroethylimidoyl chlorides. These intermediates are treated with amines and anilines to produce N-chloroethylamidines, which are converted into imidazolines upon workup with aqueous hydroxide. The method is simple and efficient and has been used to prepare a wide variety of enantiopure imidazolines, in a modular fashion, from readily available amino alcohols.     

Biosynthesis of anthecotuloide,an irregular sesquiterpene lactone from Anthemis cotula L. (Asteraceae) via a non-farnesyl diphosphate route

Retrobiosynthetic analysis of the allergenic sesquiterpene lactone, anthecotuloide, suggested that this natural product could be formed either by head to head condensation of geranyl diphosphate with dimethylallyl diphosphate, or from farnesyl diphosphate (FPP), the accepted regular sesquiterpene precursor via the rearrangement of a germacranolide precursor. Isotopic labelling of anthecotuloide has now been achieved by feeding [1-(13)C]-glucose, [U-13C6]-glucose and [6,6-(2)H2]-glucose to aseptically grown plantlets of Anthemis cotula(family Asteraceae). Analysis of labelling patterns and absolute 13C abundances using quantitative 13C NMR spectroscopy showed that the isoprene building blocks of this sesquiterpene are formed exclusively via the MEP terpene biosynthetic pathway. This was supported by results from an experiment using [U-13C6]-glucose. A deuterium labelling experiment using [6,6-(2)H2]-glucose supported the original proposal and showed that anthecotuloide is formed from a non FPP precursor. Isotope ratio mass spectrometry suggested that there were two pathways for sesquiterpene biosynthesis in A. cotula.     

GC-NCI/MS法分析海水中得克隆类物质

建立了固相萃取-气相色谱-负化学源质谱联用法(SPE-GC-NCI/MS)同时测定海水中5种得克隆类物质的方法。采用二氯甲烷进行液液萃取(LLE),萃取液经过硅胶固相萃取小柱净化后,在15 m长的DB-5HT高温毛细管气相色谱柱上分离,NCI/MS以选择离子监测模式检测目标化合物。方法中5种得克隆类物质Dec 602,Dec 603,Syn DP和Anti DP的检出限分别为0.01,0.01,0.08,0.02和0.01 ng/L,平均加标回收率分别为61%,75%,75%,87%和91%,RSD均小于5.1%。采用该法对河北近岸海域16个采样站位海水样品进行分析,所有采样站位均有得克隆类物质检出。     

Targeting abasic sites and single base bulges in DNA with metalloinsertors

The site-specific recognition of abasic sites and single base bulges in duplex DNA by sterically expansive rhodium metalloinsertors has been investigated. Through DNA photocleavage experiments, Rh(bpy)2(chrysi)3+ is shown to bind both abasic sites and single base bulges site-specifically and, upon irradiation, to cleave the backbone of the defect-containing DNA. Photocleavage titrations reveal that the metal complex binds DNA containing an abasic site with high affinity (2.6(5) x 106 M-1), comparably to the metalloinsertor and a CC mismatch. The complex binds single base bulge sites with lower affinity (approximately 105 M-1). Analysis of cleavage products and the correlation of affinities with helix destabilization suggest that Rh(bpy)2(chrysi)3+ binds both lesions via metalloinsertion, as observed for Rh binding at mismatched sites, a binding mode in which the mismatched or unpaired bases are extruded from the helix and replaced in the base stack by the sterically expansive ligand of the metalloinsertor.     

以亲核取代反应制备质子交换膜用磺化聚酰亚胺

本文先通过缩合反应合成羟端基的二酰亚胺单体, 然后利用亲核缩聚反应, 与4,4′-二氯二苯砜及3,3′-二磺酸钠基-4,4′-二氯二苯砜共聚, 制备聚合物. 该合成路线反应周期短, 对温度和溶剂等条件要求不高, 简便易得.     

带甲基侧基的环氧树脂增容剂对炭黑在丁苯橡胶中分散度的影响

用自制的带甲基侧基的环氧树脂(TMBP)作为界面增容剂, 从拉伸性能、键合胶含量、动态性能、扫描电镜和流变性能等方面, 研究了TMBP对炭黑在丁苯橡胶中分散度的影响, 并与市售通用双酚A型环氧树脂(E-51)和橡胶工业常用软化剂邻苯二甲酸二辛酯(DOP)进行了比较. 结果表明, 带甲基侧基的环氧树脂TMBP在提高炭黑分散性方面的效果远比E-51好， 其作用模式具有典型的增容特性.     

废旧塑料回收再生利用技术的新进展

塑料制品在给人类生活带来便利的同时也带来了极大的负效应,其形成的“白色污染”,直接污染土壤及地下水。废旧塑料的回收再生利用已成为急待解决的问题,是全球环保界关注的焦点。本史扼要介绍了国内外废旧塑料回收再生技术的最新进展。     

OMS-2/堇青石整体式催化剂的制备及其对二甲醚燃烧的催化性能

 以有机物为粘合剂, 采用涂覆法制备了氧化锰八面体分子筛 (OMS-2)/堇青石整体式催化剂, 采用热重-差热分析、扫描电镜、X 射线衍射、H2 程序升温还原和 O2 程序升温脱附等技术对催化剂进行了表征, 考察了有机粘合剂种类及其用量对二甲醚 (DME) 催化燃烧性能的影响. 结果表明, 在有机粘合剂聚乙烯醇 1799 (其质量含量为 3%) 的作用下, OMS-2 以相互交织的簇体均匀分布于堇青石表面, 且粘附力较强, 制备的整体式催化剂在 DME 催化燃烧中表现出最优的催化性能, 起燃温度 T10 = 169 oC, 完全转化温度 T90 = 243 oC; 催化剂使用后再经高温焙烧其活性仍能保持稳定, 表现出较高的重复使用性.