超交联微孔聚合物的制备及其应用的研究进展

超交联微孔聚合物(Hyper-cross-linked ploymers,HCPs)是一类新型多孔材料,由于其合成条件温和、成本低廉、孔尺寸可调控、表面官能团可修饰,以及耐热、耐酸碱等优点,近几年受到极大关注。在气体储存和分离、催化、去除水相中的重金属离子等方面具有明显的应用前景。本文介绍了超交联微孔聚合物的合成方法,包括通过外交联芳香化合物的方法和通过分子内或分子外交联前体的方法制备超交联微孔聚合物。总结了超交联微孔聚合物在储气,催化,废水处理等方面的应用。并对超交联微孔聚合物未来研究进行展望。     

多孔聚合物贮氢材料的研究进展

微孔聚合物由于具有较高的比表面积,因此可用作物理吸附贮氢材料.本文通过比较0.1MPa、77K下自具微孔聚合物、超交联聚合物等多孔聚合物与其它多孔贮氢材料(如碳材料、金属有机网络等)的贮氢性能,阐述了比表面积、孔尺寸及孔形貌、与氢气的作用力等因素对多孔聚合物贮氢量的影响,由于合成超交联聚合物的单体多且孔形貌容易控制,因此超交联聚合物成为具有发展潜力的贮氢聚合物.     

编织超交联微孔聚合物的研究进展

超交联微孔聚合物因具有比表面积高、合成条件温和、单体来源广泛、催化剂廉价易得等优点而得到广泛关注。近年来,作为一种简单有效的新合成策略,外交联"编织"法成为制备超交联微孔聚合物主要方法之一。该方法可以从低官能度化合物制备得到高比表面积和孔径可调控的超交联聚合物,进一步扩大了构筑单体的选择范围,还可降低副产物的危害,为低成本大规模制备超交联聚合物材料提供了可能。本文对编织超交联聚合物的合成方法进行了总结,并对其在形貌控制中的应用、所得编织微孔聚合物的应用(气体储存和分离、催化、有毒物质吸附、药物控制释放、储能、色谱分离、传感以及碳材料前体等)进行了介绍,最后对外交联"编织"法所面临的问题和挑战、发展前景进行了展望。     

反应性模板剂诱导原位超交联法制备层次孔聚合物和碳材料

首先设计合成出新颖反应性SiO₂模板剂(即表面含苄基氯化学官能团的SiO₂纳米球), 然后利用1,4-对二氯苄(DCX)作为自交联功能单体, 成功地发展了一种“反应性模板剂诱导原位超交联法”制备层次孔聚合物(HPP)及其层次孔碳材料(HPC)的新思路: 一方面, DCX作为有机单体分子, 可与SiO₂纳米球表面的苄基氯化学官能团原位反应形成共价键, 极大地增强了聚合物前驱体和模板剂的相互作用力, 有利于模板剂的高度单分散和表面均匀包覆共价有机聚合物; 另一方面, DCX分子可以发生自交联反应, 免去交联剂的额外添加, 简化了制备流程. 利用该法所得HPP具有独特的微孔-中孔-大孔呈层次化分布的孔结构特征: 微孔壳-大孔腔空心纳米球之间相互交联堆叠形成丰富的中孔和大孔, 各层次纳米孔道紧密相连. 进一步地, HPP的共价有机骨架具有超交联化学结构, 可确保这类层次孔纳米结构在高温碳化过程中的稳定继承, 由此制得HPC, 其BET比表面积为756 m²·g^-1.     

基于金属配位和主客体相互作用分级自组装构筑超分子凝胶

将金属配位和主客体相互作用引入到同1个超分子体系中,设计合成了2个超分子单体1和2.通过这2个超分子单体分级自组装形成的交联网状超分子聚合物构建了一种多重刺激响应性和良好自修复性能的超分子凝胶.同时,进一步将具有聚集诱导发光性能的四苯乙烯引入到这种超分子体系中,以赋予超分子体系新颖的发光性能.单体分子1是由中间为双苯并24-冠-8的冠醚连接2个四苯基乙烯荧光生色团,两端为2个三联吡啶分子构成的1个主体分子.单体分子1两端的三联吡啶基团可以与过渡金属Zn(OTf)2进行金属配位形成线型超分子聚合物3;而中间的冠醚基团与双二级铵盐客体分子2通过主客体相互作用进一步形成交联超分子聚合物4.当该交联超分子聚合物的浓度达到30 mmol/L时,可形成荧光超分子聚合物凝胶.通过核磁共振(1H-NMR和DOSY)与黏度等测试方法,证明了线形和交联超分子聚合物的形成,并进一步通过流变的测试证明了超分子聚合物凝胶的形成及其良好的自修复性能.除此之外,由于引入的主客体相互作用以及金属配位固有的刺激响应性,该荧光超分子聚合物凝胶表现出对温度、p H值、K+离子和竞争配体的刺激响应性能.     

可紫外光交联氟代聚芳醚的合成及性能研究

以丙酮酸、苯甲醚为原料合成了1,1-双(4-甲氧基苯基)(BMPE)乙烯单体,并通过去甲基反应得到了含可交联基团的二酚单体1,1-双(4-羟基苯基)乙烯(BHPE),并且用核磁共振、飞行质谱及元素分析表征了单体的结构,DSC测试了单体的熔点.并将BHPE与全氟联苯(DFBP)在氟化钾和氢化钙的催化作用低温下进行缩聚反应,得到了一种可紫外辐照交联的氟代聚芳醚.通过核磁共振证明了所合成的单体以及聚合物的结构,凝胶渗透色谱(GPC)测定了聚合物的分子量.傅立叶变换红外光谱分析了聚合物紫外辐照下的交联反应.所合成的氟代聚芳醚在室温下可溶于氯仿、四氢呋喃等有机溶剂,紫外交联后不溶于任何有机溶剂.且合成的聚合物具有良好的热稳定性能(玻璃化转变温度为160℃,交联后的5%热失重为465℃).     

不同交联剂对甲基丙烯酸-β-羟乙酯/E-51双甲基丙烯酸酯聚合物水凝胶性能的影响

以水溶性单体甲基丙烯酸-β-羟乙酯(HEMA)与大分子交联剂E-51双甲基丙烯酸酯(E-51-DMA)(质量比HEMA/E-51-DMA=90/10)为主要原料,分别引入了5种小分子交联剂:N,N′-亚甲基双丙烯酰胺(MBA)、二乙烯基苯(DVB)、双甲基丙烯酸乙二醇酯(EDMA)、1,1,1-三(丙烯酰氧甲基)丙烷(TAP)和2,2,2-三(丙烯酰氧甲基)乙醇(TAE),采用本体聚合方法合成了5个系列的聚合物水凝胶.研究了小分子交联剂的类型及用量对水凝胶溶胀性能、杨氏模量以及有效交联密度ve和聚合物-水相互作用参数χ的影响,并比较了不同交联剂的交联效率.结果表明,随着小分子交联剂用量的增大,水凝胶平衡含水量EWC逐渐降低,聚合物体积分数2逐渐增大,反映聚合物网络结构的有效交联密度ve以及热力学参数聚合物-水相互作用参数χ值也随之增大.通过理论交联密度和有效交联密度的线性拟合,得到所选用的5种小分子交联剂在E-51-DMA10/HEMA90水凝胶体系中的交联效率,其顺序为DVB>EDMA>TAE>MBA≈TAP.     

室温交联型硅丙微胶乳的合成研究Ⅲ.聚合工艺对聚合稳定性及胶膜性能的影响

采用两种聚合工艺(种子微乳液聚合法和单体预乳化法)分别合成了室温交联型有机硅改性丙烯酸酯聚合物微胶乳，研完了不同工艺条件对聚合稳定性、乳胶粒径和胶膜的结构性能的影响．     

LCST可调的温度响应型核交联星型聚合物的合成与相变行为

通过"臂优先"的途径和可逆加成-断裂转移(RAFT)自由基聚合合成了以聚(聚乙二醇甲醚丙烯酸酯-co-丙烯酸乙氧基乙氧基乙酯)(P(PEGA-co-DEGA))为线型外臂的温度响应型核交联星型聚合物(CCSP)。采用傅里叶红外光谱(FT-IR)、核磁共振氢谱(~1H-NMR)和凝胶渗透色谱(GPC)等手段对合成产物进行了表征,同时以紫外-可见光谱(UV-Vis)对该核交联星型聚合物的相变行为进行了研究。结果表明,所制备的核交联星型聚合物具有可调控的低临界溶解温度(LCST),通过改变外臂温敏单体配比和聚合物溶液的pH,可控制所得CCSP的LCST在49～82℃可调。而且与线型外臂相比,CCSP由于其独特的拓扑结构具有更窄的相转变温度范围和更灵敏的相变过程。     

可控活性聚合多乙烯基单体制备新型单链超内环化聚合物的研究历史及进展

多乙烯基单体因其方便易得、固有的反应多活性位点而一直是合成多种复杂拓扑结构聚合物的理想单体;然而Flory-Stockmayer(F-S)均相场理论及广泛的前期尝试已证实多乙烯基单体的聚合会在极低转化率(10%)下形成凝胶,而无法进行可控聚合.近年来,可控活性聚合方法的发展为动力学控制下的多乙烯基单体聚合奠定了基础,并成功合成多种具有不同复杂结构的聚合物.特别地,合成了具有新颖拓扑结构的单链超内环化聚合物.本文综述了近年来多乙烯基单体聚合的历史,动力学控制下的可控活性聚合机理以及单链超内环化聚合物的聚合过程、结构特征、应用等,展望了该新颖结构聚合物的应用前景,并对多乙烯基单体的可控活性聚合领域的未来发展提出了建议.     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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%).