以硝基、氨基修饰改性聚苯醚

将聚苯醚硝化、还原,分别合成了硝化聚苯醚和胺化聚苯醚,最高硝基、氨基取代度分别为95%、65%.讨论了各种反应条件对取代度的影响,并对修饰改性的聚苯醚进行了表征。     

苯酰化聚苯醚—聚苯乙烯共混物相容性研究

采用DSC方法研究了聚苯乙烯和苯甲酰化聚苯醚共混体系的相容性。相容共混体系Gordon-TayIov方程K参数随苯甲酰化程度(取代度)增加而变小,其玻璃化转变区随取代度增加而变宽,取代度大于76mol％时,共混物呈现双玻璃化转变。A~(49)ppo/pS_(19)共混体系热诱导相图同时存在高和低临界共溶温度,且此相行为是可逆的。     

苯酰化聚苯醚/聚苯乙烯共混物相容性研究

采用DSC方法研究了聚苯乙烯(PS)和苯甲酰化聚苯醚(APPO)共混体系的相容性.相容共混体系Gordon-Taylor方程K参数随苯甲酰化程度(取代度)增加而变小,其玻璃化转变区随取代度增加而变宽,取代度大于76mol％时,共混物呈现双玻璃化转变.APPO/PS共混体系热诱导相图同时存在LCST和UCST现象,且相行为是可逆的.     

苯酰化聚苯醚/聚苯乙烯共混物相容性研究

 采用DSC方法研究了聚苯乙烯(PS)和苯甲酰化聚苯醚(APPO)共混体系的相容性.相容共混体系Gordon-Taylor方程K参数随苯甲酰化程度(取代度)增加而变小,其玻璃化转变区随取代度增加而变宽,取代度大于76mol％时,共混物呈现双玻璃化转变.APPO/PS共混体系热诱导相图同时存在LCST和UCST现象,且相行为是可逆的.     

取代基对PPC/聚苯醚羧酸酯共混体系相容性的影响

由二氧化碳活化并与环氧丙烷共聚而成的脂肪族聚碳酸酯(PPC)是一类有发展前途的新型高分子弹性体。研究它与其它高聚物的混容性及混容机制对于开拓这一新材料的应用领域具有十分重要的意义。本文合成了一系列不同取代度和不同链长酯基的聚苯醚羧酸酯[E(x)-C^yPPO]^[3],探索了PPC与各聚苯醚狡酸醋的混容性,讨论了聚苯醚梭酸酷的取代度及侧基链长对PPC/E(x)-C^yPPO共混体系混容性的影响。     

改性PPO的溶解性能和溶度参数的初步估计

研究了聚苯醚PPO、羧化PPO、苯酰化PPO、苯磺酰化PPO和磺化PPO在不同溶剂中的溶解能力,分别讨论了各种取代基以及取代度对聚合物溶解性能的影响,由PPO衍生物的特性粘数估算了它们的溶度参数。     

磺化聚苯醚的制备与表征

磺化聚苯醚的制备与表征汪传清，黄玉惠，丛广民（中国科学院广州化学研究所广州５１０６５０）关键词聚苯醚，磺化，磺化度，磺化聚苯醚聚苯醚是一种优良的工程塑料，对它进行修饰改性以获得各种功能材料的研究近十多年来十分活跃’‘，’，‘’．磺化聚苯醚（ＳＰＰＯ）...     

多取代苯的自位硝化和溴化反应

系统地研究了苯环取代烷基和侧链取代基对自位硝化反应的影响，详细地讨论了脱溴甲基的机理，多取代苯的正常硝代与自位３硝化是一对竞争反应；侧链酯基的存在是自位硝化的必要条件；苯环上取代基的空间效应是自位硝化的充分条件，六元环过滤态很可能为自位硝化反应提供了一个能量有上利的途径。     

以离子-离子相互作用增强共混相容性Ⅰ.聚苯醚离聚体/聚(苯乙烯-乙烯吡啶)共混体系

本文从溶液行为和固体热行为对聚（2，6-二甲基1，4-苯醚）（PPO）离聚体（磺化聚苯醚或接化聚苯醚）／聚（苯乙烯-4-乙烯吡啶）（PS－VP）共混物进行了研究。DSC研究表明磺化度为7．7％mol的SPPO／PS－VP和羧化度为15％molCPPO炉S－VP在整个组成范围都是相容的。溶液行为研究表明，与对应的PPO／PS－VP共混物相比，这两个系列的共混物都表现出较高的比浓粘度。这是由于聚苯醚离聚体上的酸基发生质子转移，两组分间强烈的离子-离子相互作用导致分子间的络合，从而使比浓粘度的提高，也正是这种离子-离子相互作用使得这两对共混物完全相容。     

单取代芳烃的硝化

以甲苯、乙苯、异丙苯、叔丁基苯、氟苯等为硝化底物,通过混酸硝化得到这些单取代芳烃转化率最大时的混酸硝化强度φ。 运用密度泛涵理论,在B3LYP/6-311G**水平上优化了9种单元芳烃的几何构型,计算苯环上C原子电荷分布。 讨论了9种取代基的定位效应,以苯环取代基以外环上C原子总净电荷QRΣC(2~6)表示单取代苯的硝化反应活性与硝化强度φ之间的关系。 实验结果表明,烷基苯、卤苯、硝基苯的硝化反应活性与其混酸硝化转化率达最大时的混酸硝化强度φ呈良好的线性关系。     

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%.     

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.     

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.     

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.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.