多孔聚合物骨架的超声及微波辅助合成

首次采用超声与微波辅助合成方法制得数种高比表面积吸附纤维和树脂新材料。研究表明,1)分别以4,4’-二氯甲基-联苯(CMDP)、1,4-二氯甲基苯(XDC)以及FeCl3为单体和催化剂,采用超声辅助Fridel-Crafts烷基化自聚合反应制得比表面积可达1320m2/g的超高交联多孔吸附树脂新材料;2)以PP-ST-DVB基纤维为基体,分别采用超声或超声-微波辅助Fridel-Crafts后交联反应制得比表面积可达84.25m2/g和83.96m2/g的超高交联吸附纤维新材料。与现有多孔高分子骨架制备方法相比,这种多孔聚合物合成新技术可有效克服液固相接枝聚合反应中受热不均所带来的种种弊病,且具有促进溶解(溶胀)和反应时间大幅缩短的优点。     

大网均孔阴离子交换纤维的合成及其对苯酚吸附性能研究

以大网均孔吸附纤维(MIAF)为原料,将MIAF进行氯甲基化、胺化,制得大网均孔弱碱性阴离子交换纤维(MIAEF),探讨了氯甲基化过程中的影响因素,并初步研究了MIAEF对水溶液中苯酚的吸附性能,MIAEF和弱碱性离子交换纤维(NormalAnionExchangeFiber,NAEF),对水溶液中苯酚动力学性能的比较研究表明:MIAEF对水溶液中的苯酚表现出更好的吸附性能,平衡时吸附量达1.368mmol/g,是NAEF的3倍以上。     

四氯化碳存在下大孔苯乙烯-二乙烯苯共聚物的后交联反应

对在四氯化碳存在下 ,大孔St DVB共聚物以三氯化铝为催化剂的后交联反应进行了研究 .结果表明 ,起始共聚物的合成条件 ,包括交联剂DVB的用量 ,致孔剂的性质及其与单体的配比 ,对后交联产物的孔结构有重要影响 .以良溶剂甲苯为致孔剂及采用较高的DVB用量 ,所合成的起始共聚物经后交联后 ,比表面积很容易达到或超过 10 0 0m2 /g .一般情况下 ,后交联产物的孔容增加 ,孔径减小 ,孔结构稳定性明显提高 .当起始共聚物的DVB含量较低时 ,后交联反应以四氯化碳的参与为主 ;当DVB含量较高时 ,后交联反应以起始共聚物中固有的悬挂双键的参与为主     

基于Diels-Alder反应的热可逆交联聚乙烯的合成

分别以Ziegler-Natta催化剂和茂金属催化剂(rac-Et(Ind)_2ZrCl_2)引发乙烯/6-呋喃-1-己烯(FH)共聚合,合成了侧基含有呋喃取代基的聚乙烯。再以1,6-二马来酰亚胺基己烷(BMH)为交联剂,通过Diels-Alder反应制备了交联聚乙烯。利用~1H-NMR、DSC等对乙烯/FH共聚物结构进行了表征,利用FTIR、拉伸测试、蠕变实验等对交联聚乙烯的结构与性能进行测定。结果表明,通过改变马来酰亚胺与呋喃的比例可以调节聚乙烯的交联程度,同时Diels-Alder反应的热可逆性赋予交联聚乙烯重复加工性。     

低交联聚乙烯后交联的研究(Ⅱ)

本文用四氯化碳为后交联剂,通过Friedel—Crafts反应使低交联聚苯乙烯发生后交联,形成大孔树脂。用正交试验法考查了反应时间,反应温度,后交联剂用量,催化剂用量和溶剂组成对树脂孔结构的影响。后交联得到的树脂的比表面积和孔容分别可达到484m~2/g和0.42ml/g。     

环氧氯丙烷橡胶的热可逆共价交联

以环戊二烯二羧酸钾 [DCPD(COOK) 2 ]为交联剂 ,采用溶液反应法使环氧氯丙烷橡胶 (环氧氯丙烷均聚物 ,CER)交联 ,制得了凝胶含量达 88 75 %的交联CER ,研究了溶剂种类、反应温度、催化剂及交联剂用量对凝胶形成量的影响 .IR谱证明 ,DCPD(COOK) 2 与CER发生双端酯化而交联 ;反应溶解性试验表明 ,该共价交联聚合物具有热可逆转化特性 ,热可逆转化百分率随反应温度的提高、交联剂用量的增多而下降     

硫酸铜含量对硫酸铜与丁腈橡胶之间配位交联反应的影响

利用丁腈橡胶(NBR)的可配位侧基——腈基(—CN)与金属盐硫酸铜(CuSO4)的铜离子(Cu2+)之间的配位反应制备了一种配位交联CuSO4/NBR.影响该配位交联反应的因素众多,如热压温度、热压时间、增塑剂等等,考察了CuSO4含量对其的影响.通过X射线光电子能谱(XPS)、动态力学分析(DMA)、差示扫描量热分析(DSC)等手段对CuSO4与NBR之间的配位交联反应进行了分析,并对所得配位交联的CuSO4/NBR进行了交联密度及力学性能的测试.结果发现,随CuSO4含量的不断增加,CuSO4与NBR的配位交联程度逐渐增强,且所得配位交联CuSO4/NBR显示出从典型橡胶到韧性塑料再到脆性塑料的力学转变特性.另外,通过扫描电子显微镜(SEM)及X射线能谱仪(EDX)对材料的微观结构进行了分析,发现CuSO4在聚合物基体中不仅充当交联剂的角色,而且还起着增强填料的作用.     

SiO2交联剂交联MMA聚合制备PMMA/SiO2纳米复合材料

用SiO2交联剂(SiO2HPA)交联甲基丙烯酸甲酯(MMA)自由基聚合制备PMMA SiO2纳米复合材料。采用两步法将可聚合乙烯基单体以化学键的形式键接到SiO2表面合成SiO2交联剂,首先利用过量的甲苯2,4二异氰酸酯(TDI)对SiO2纳米粒子表面进行化学修饰合成出表面带有高反应活性NCO基团的功能化SiO2粒子(SiO2TDI),SiO2TDI与丙烯酸羟丙酯(HPA)反应合成SiO2交联剂。系统研究了MMA单体与SiO2交联剂投料比及聚合时间对聚合反应的影响。此外,利用红外光谱(FT IR)、DSC、TGA、可见光光谱仪等实验手段对纳米复合材料进行了表征分析。结果表明,纳米SiO2粒子在复合材料中起着物理交联点和化学交联点作用,复合材料玻璃化转变温度(Tg)明显地高于其纯PMMA的玻璃化转变温度,随着纳米SiO2粒子含量的增加,复合材料玻璃化温度升高,而透明度明显降低。     

邻硝基乙苯在超高交联树脂合成中的应用研究

本文用邻硝基乙苯为溶剂,替代工业上常用的剧毒的硝基苯对氯甲基化聚苯乙烯（简称氯球）进行付氏后交联反应,详细地研究了反应条件如：反应温度、催化剂的种类及用量等对树脂孔结构性能的影响。并在最佳反应条件下进行放大实验,合成出的后交联树脂的比表面为817m2／g,孔容为0．727ml／g,平均孔径为10．9nm。     

热可逆共价交联氯化聚乙烯的制备和性能

以双环戊二烯二羧酸钾 [DCPD(COOK) 2 ]为交联剂 ,通过共混反应法制得了共价交联的氯化聚乙烯(CPE)热塑性弹性体 (TPE) ,研究了共混反应条件 (温度、时间及交联剂用量等 )对TPE物性的影响 .反应溶解性和IR测定数据证明 ,DCPD(COOK) 2 与CPE分子链上的活性氯反应形成共价酯键而交联 ;物性测定数据表明 ,交联CPE的主要力学性能接近CPE常规硫化胶 ,不同的是该交联聚合物具备可塑性 ,经反复加工三次后 ,其力学性能还略有提高     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.