一种超支化半芳香聚酰胺的合成及表征

以乙二胺和均苯三甲酰氯为原料通过A2+B3方法合成超支化半芳香型聚酰胺(HBPE),研究了反应条件对聚合反应的影响,利用傅里叶变换红外光谱、核磁共振谱等对合成的超支化半芳香聚酰胺进行了结构表征。研究结果表明,控制单体官能团摩尔比(COCl∶NH2)为1.1∶1,催化剂LiCl浓度为0.0125g/L,反应温度为50℃,反应时间为14h,制得的HBPE的相对分子质量最大,其最大重均相对分子质量及其分布分别为4.3×104和1.59。热重分析结果表明HBPE具有较好的热稳定性。     

PVP负载钯纳米丝状催化剂的制备及催化加氢性能

用电纺丝技术和加热交联技术制备了聚乙烯吡咯烷酮(PVP)负载纳米钯的纳米丝状催化剂PVP-Pd,并对所制备的催化剂进行了SEM,TEM,UV和TG的表征。利用PVP-Pd对烯烃和硝基苯的催化氢化反应研究了所制备催化剂的催化性能,结果表明纳米纤维态PVP-Pd催化剂在室温、氢气条件下催化氢化α-辛烯和环己烯的转化率可以达到100%,对硝基苯也有很好的催化活性。     

hcp晶相的Ni纳米颗粒对不同官能团的通用催化加氢活性（英文）

催化加氢是生产高附加值燃料和精细化学品的重要工业途径,但需要高效的催化剂,尤其是廉价的非贵金属催化剂.迄今为止,大多数高性能催化加氢催化剂都是由贵金属材料制成,并且这些催化剂都只能用于催化一种或几种特定的反应.在这里,我们例证了一种晶相工程方法,其能赋予Ni纳米颗粒(NPs)卓越的、广谱的内在催化加氢活性.这种负载于碳载体上含有hcp晶相的Ni NPs催化剂通过直接碳化热解Ni咪唑MOF前驱体获得.在纯水中,含hcp相的Ni NPs对硝基、醛、酮、烯烃和N杂环化合物表现出前所未有的加氢催化活性,优于类似物fcc-Ni和目前报道的其他过渡金属催化剂.密度泛函理论计算表明,hcp-Ni通过增强底物吸附强度和降低速率决定步骤的反应势垒能共同来提高内在催化氢化活性.我们预计这项工作中揭示的晶相工程设计方法将适用于其他类型的反应.     

以氧化石墨烯为酸催化剂制备2,5-二甲基-N-苯基吡咯（英文）

介绍了氧化石墨烯作为一种高效且可回收的催化剂应用于2,5-己二酮与苯胺通过Paal-Knorr缩合反应合成N-取代吡咯。研究了反应时间、反应温度、溶剂、催化剂用量以及苯胺与2,5-己二酮的摩尔比对2,5-二甲基-N-苯基吡咯收率的影响。通过原位核磁技术在分子水平上跟踪了Paal-Knorr缩合的反应过程。结果表明在25℃下通过氧化石墨烯的催化作用反应6 h后吡咯的最大收率可达到90%。氧化石墨烯易回收,且经5次回收使用后还能表现出很好的循环使用性和高催化性能。     

新型工程塑料—聚芳香醚酮

聚芳香醚酮(PEEK)是七十年代末期由英国 ICI 公司开发的一种结晶型线性芳香族聚合物,其分子结构式为: 目前,英国ICI公司已有专门厂家进行小批量生产,其商品     

兰州化物所高效不对称氢化反应研究取得新进展

发展实用而高效的手性催化剂用于不对称有机反应是有机合成化学的研究热点之一。通常,刚性的手性配体可在金属中心周围构筑特殊的手性立体微环境,以有效控制反应物分子的空间取向和反应进程,使其发挥特异的对映选择性和活性。目前,用于芳香酮不对称氢化反应的催化剂大多为手性双胺双膦钌配合物,而经济型非手性膦结合手性双     

高分子金属络合物催化剂的合成及其催化氢化的应用

本文综述了高分子金属络合物催化剂的合成及其在催化氢化反应中的应用，对该领域目前存在的问题及进一步的发展提出了看法。     

联苯基聚芳亚胺的合成与热性能

以4,4-二溴联苯和芳香二胺为单体,以三(二亚苄基丙酮)二钯为催化剂,1.1'-联萘-2.2'-二苯膦(BINAP)为配体,由钯催化的胺基化反应缩聚合成了联苯基聚芳亚胺.其结构由红外、核磁氢谱和元素分析表征,表征结果与目标结构吻合良好.通过DSC和TG对其热性能进行分析,结果表明:联苯基聚芳亚胺具有良好的热稳定性(Tg＞250℃;TD＞510℃).     

二胺基二苯基砜／环氧树脂固化动力学研究

研究了二胺基二苯基砜/双酚A环氧树脂体系预凝胶阶段的反应动力学。采用官能团滴定法测定了不同反应条件下的动力学数据,经计算机处理后,发现该体系在预凝胶阶段的反应符合二级反应模型,求出了伯、仲胺基与环氧基反应的活化能分别为60.73 kJ/mol和66.17kJ/mol。依此,本文对该体系的反应机理及芳香二胺中的取代效应问题作了一些探讨。     

硅钨酸催化合成缩醛(酮)

以硅钨酸为催化剂,对以乙酰乙酸乙酯、环己酮、苯甲醛和正丁醛与二元醇(乙二醇,1,2-丙二醇)为原料合成8种缩醛(酮)的反应条件进行了研究,较系统地研究了醛/酮与二元醇量比、催化剂用量、反应时间诸因素对收率的影响.结果表明,在醛/酮与二元醇(乙二醇,1,2-丙二醇)的投料摩尔比为12.1,催化剂的用量占反应物料总质量的1.0%,反应时间为1h条件下,8种缩醛(酮)的产率在55.2%～80.0%之间.     

Polar-liquid, derivatized cyclodextrin stationary phases for the capillary gas chromatography separation of enantiomers

A new class of hydrophilic, relatively polar liquid, cyclodextrin (CD) derivatives have been used as highly selective chiral stationary phases (CSPs) for capillary gas chromatography (GC). Several possible requirements for liquidity in CD derivatives are discussed. O-(S)-2-Hydroxypropyl derivatives of alpha-, beta-, and gamma-cyclodextrins were synthesized, exclusively characterized, permethylated, and evaluated for enantioselectivity. Seventy pairs of enantiomers were resolved. They represent a wide variety of structural types and classes of compounds including chiral alkyl amines, amino alcohols, epoxides, pyrans, furans, sugars, diols, esters, ketones, bicyclic compounds, alcohols, and so on. Many of these compounds were not aromatic and cannot be resolved on any known liquid chromatographic CSP. Often, these enantiomers had far less functionality than required for LC separation. General properties of these CSPs as well as possible insights into the separation mechanism are discussed.     

基于甲壳素的手性分离材料

甲壳素是一种丰富的可再生资源,将甲壳素在碱性条件下脱去乙酰基得到壳聚糖,甲壳素和壳聚糖分子骨架有大量的手性碳原子存在,且含有较多的羟基、乙酰氨基或氨基活性官能团,容易进行化学改性得到有较好手性识别能力的衍生物,且它们能以膜、纤维、凝胶及微球等不同形式出现,可作为各种手性分离介质。概述了近年来甲壳素衍生物作为手性分离介质的重要研究进展,主要包括甲壳素及其衍生物的色谱手性固定相、手性分离膜、分子印迹聚合物。重点介绍了这些手性分离介质的结构、制备及性能,并展望了甲壳素衍生物手性分离介质的研究前景。     

Germania-based, sol-gel hybrid organic-inorganic coatings for capillary microextraction and gas chromatography

Germania-based, sol-gel hybrid organic-inorganic coatings were developed for capillary microextraction and gas chromatography (GC). Being an isostructural analogue of SiO2, GeO2 is compatible with the silica network. Because of this similarity, germania-based materials possess great potential for being used in the areas of chromatographic separation and sample preparation. These possibilities, however, remain practically unexplored. To our knowledge, this is the first instance that a germania-based hybrid sol-gel material is used as a sorbent in analytical sample preparation or chromatographic separation. Tetramethoxygermane was used as a precursor to create a sol-gel network via hydrolytic polycondensation reactions performed within a fused-silica capillary. The growing sol-gel germania network was simultaneously reacted with an organic ligand that contained sol-gel-active sites in its chemical structure. Three different sol-gel-active ligands were used: (a) hydroxy-terminated poly(dimethylsiloxane), (b) hydroxy-terminated poly(dimethyldiphenylsiloxane), and (c) 3-aminopropyltrimethoxysilane. Sol-gel germania-coated capillaries of desired polarity and extraction selectivity were prepared by using an appropriately selected sol-gel-active ligand in the sol solution. These capillaries were further used to extract trace concentrations of polycyclic aromatic hydrocarbons, aldehydes, ketones, alcohols, phenols, and free fatty acids from aqueous samples. The extracted solutes were further analyzed by GC-FID. The new germania-based coatings showed excellent stability under harsh operation conditions involving extreme pH values, high temperatures, and aggressive solvents. Our preliminary results also indicate that sol-gel hybrid germania coatings have the potential to offer great analytical performance as GC stationary phases.     

Combining the enantioselectivities of L-valine diamide and permethylated beta-cyclodextrin in one gas chromatographic chiral stationary phase

An L-valine diamide chiral selector was attached to a polysiloxane through a long hydrocarbon spacer giving rise to a chiral stationary phase (CSP), Chirasil-Val-C11. The enantioselective properties of this readily accessible diamide CSP under gas chromatographic conditions were found to be similar to that of the commercially available Chirasil-Val CSP prepared by a polymer-analogous route. A new binary CSP, Chirasil-DexVal-C11, was synthesized by means of simultaneous attachment of both the L-valine diamide and permethylated beta-cyclodextrin selectors to a polysiloxane using platinum-catalyzed hydrosilylation, thereby overcoming the immiscibility problem known for Chirasil-Val and Chirasil-Dex. This binary CSP retained both the enantioselectivity of Chirasil-Val-C11 toward alpha-amino acid derivatives and the unsurpassed enantioselectivity of Chirasil-Dex toward underivatized chiral alcohols, ketones, and hydrocarbons. Furthermore, it was shown that the presence of the cyclodextrin selector in Chirasil-Val-C11 significantly improved the enantioseparation of proline, which represented a problematic amino acid on diamide CSPs.     

Single-walled carbon nanotubes used as stationary phase in GC

Single-walled carbon nanotubes (SWNTs) have high surface area, high adsorption ability, and nanoscale interactions. In this study, capillary columns including SWNTs, ionic liquid (IL), and IL + SWNTs for GC were prepared. The separation results showed that SWNTs possessed a wide selectivity toward alkanes, alcohols, aromatic compounds, and ketones, and a SWNT capillary column was a very useful GC column for the separation of gas samples. Coating the IL stationary phase on the SWNT capillary column, the SWNTs were able to improve chromatographic characteristic of ionic liquid. Comparing the IL coated on three graphite carbon black capillary columns, which were prepared by dynamic coating, static coating, and chemical bonding the Carbopack C with on SWNTs capillary column, the capacity factors were much higher on the SWNT column. The SEM showed that SWNTs could be bonded to the inner surface of capillary tubing, and most of them were linked end-to-end to form a layer of network structure of skeletons resulting in a high surface area, which increased the interactions between stationary phase and analytes. This is the first single-wall carbon nanotubes bonded to the fused-silica capillary tubing. In the first approach, SWNTs assist ionic liquid with enhanced chromatographic characteristic in GC. This work indicates that SWNTs make it possible to extend the application range on the newly prepared chromatographic stationary phases for GC.     

Sol-gel capillary microextraction

Sol-gel capillary microextraction (sol-gel CME) is introduced as a viable solventless extraction technique for the preconcentration of trace analytes. To our knowledge, this is the first report on the use of sol-gel-coated capillaries in analytical microextraction. Sol-gel-coated capillaries were employed for the extraction and preconcentration of a wide variety of polar and nonpolar analytes. Two different types of sol-gel coatings were used for extraction: sol-gel poly(dimethylsiloxane) (PDMS) and sol-gel poly(ethylene glycol) (PEG). An in-house-assembled gravity-fed sample dispensing unit was used to perform the extraction. The analysis of the extracted analytes was performed by gas chromatography (GC). The extracted analytes were transferred to the GC column via thermal desorption. For this, the capillary with the extracted analytes was connected to the inlet end of the GC column using a two-way press-fit fused-silica connector housed inside the GC injection port. Desorption of the analytes from the extraction capillary was performed by rapid temperature programming (at 100 degrees C/min) of the GC injection port. The desorbed analytes were transported down the system by the helium flow and further focused at the inlet end of the GC column maintained at 30 degrees C. Sol-gel PDMS capillaries were used for the extraction of nonpolar and moderately polar compounds (polycyclic aromatic hydrocarbons, aldehydes, ketones), while sol-gel PEG capillaries were used for the extraction of polar compounds (alcohols, phenols, amines). The technique is characterized by excellent reproducibility. For both polar and nonpolar analytes, the run-to-run and capillary-to-capillary RSD values for GC peak areas remained under 6% and 4%, respectively. The technique also demonstrated excellent extraction sensitivity. Parts per quadrillion level detection limits were achieved by coupling sol-gel CME with GC-FID. The use of thicker sol-gel coatings and longer capillary segments of larger diameter (or capillaries with sol-gel monolithic beds) should lead to further enhancement of the extraction sensitivity.     

Analytical- and preparative-scale isoelectric focusing separation of enantiomers

Isoelectric focusing has been used to achieve the analytical- and preparative-scale separation of the enantiomers of amphoteric analytes. By considering the simultaneous multiple equilibria involved in the chiral recognition process, a model has been developed to describe the magnitude of the ΔpI value that develops between the enantiomers in the presence of a noncharged chiral resolving agent, such as a noncharged cyclodextrin. Theoretical analysis of the model indicates that three kinds of IEF enantiomer separations are possible: aniono-selective and cationo-selective, when only the identically charged forms of the enantiomers bind selectively to the resolving agent, and duo-selective, when the differently charged forms of the enantiomers bind selectively to the resolving agent. The model predicts that the ΔpI vs cyclodextrin concentration curves approach limiting ΔpI values which can be as large as 0.1, even when the binding constants of the enantiomers differ only by 10%. The parameters of the model can be readily determined by free solution capillary electrophoretic or pressure-mediated capillary electrophoretic experiments. The validity of the proposed model has been tested with hydroxypropyl β-cyclodextrin as resolving agent and dansyl phenylalanine as probe. Capillary IEF enantiomer separations have been achieved using both ampholytes and binary propionic acid-serine buffers (Bier's buffers). Preparative-scale IEF enantiomer separations with production rates as high as 1.3 mg/h have been achieved in an Octopus continuous free-flow electrophoretic system.     

Analysis of saturated hydrocarbons by redox reaction with negative-ion electrospray Fourier transform ion cyclotron resonance mass spectrometry

A novel technique was developed for characterization of saturated hydrocarbons. Linear alkanes were selectively oxidized to ketones by ruthenium ion catalyzed oxidation (RICO). Branched and cyclic alkanes were oxidized to alcohols and ketones. The ketones were then reduced to alcohols by lithium aluminum hydride (LiAlH(4)). The monohydric alcohols (O(1)) in the products obtained from the RICO and RICO-LiAlH(4) reduction reactions were characterized using negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) for identification of iso-paraffins, acyclic paraffins and cyclic paraffins. Various model saturated compounds were used to determine the RICO reaction and ionization selectivity. The results from the FTICR MS analysis on the petroleum distillates derived saturated fraction were in agreement with those from field ionization gas chromatography time-of-flight mass spectrometry (FI GC-TOF MS) analysis. The technique was also used to characterize a petroleum vacuum residue (VR) derived saturates. The results showed that the saturated molecules in the VR contained up to 11 cyclic rings, and the maximum carbon number was up to 92.     

Monolayer-protected gold nanoparticles as a stationary phase for open tubular gas chromatography

The use of a thin film of monolayer-protected gold nanoparticles (MPNs) as a stationary phase for gas chromatography (GC) is reported. Deposition of a MPN film was obtained in a 2-m, 530-microm-i.d. deactivated silica capillary using gravity to force the solution containing the MPN material through the capillary. By SEM analysis, the average film thickness was determined to be 60.7 nm. The retention behavior for the dodecanethiol MPN column was studied using four compound classes (alkanes, alcohols, aromatics, ketones), and retention orders were objectively compared to a commercially available column (AT-1, 100-nm film thickness). Separation of an eight-component mixture was performed using both isothermal and temperature-programming methods with the dodecanethiol MPN phase and compared to an isothermal separation with the AT-1 phase. The AT-1 phase separation had an efficiency, N, of 6200 (k' = 0.33) while the dodecanethiol MPN phase separation had an efficiency, N, of 5700 (k' = 0.21) for the same analyte, octane. The reduced plate height, h, for octane was found to be less than 1 at the optimum linear flow velocity, indicating the MPN column operated near the optimum possible performance level. Robustness of the MPN phase is also discussed with consistent performance observed over several months. Overall, MPNs appear promising as a stationary-phase material for GC and as an experimental platform to study their thermodynamic and mass-transfer properties.     

十二烷基苯磺酸钾色谱固定相及其毛细管柱的研究

本文合成了十二烷基苯磺酸钾色谱固定相,并制备了毛细管色谱柱,研究了其柱性能和分离能力。实验表明,十二烷基苯磺酸钾色谱固定相对烷烃、芳香烃、酯类、醇类等具有较强的选择分离能力,制成的毛细管柱具有较高的柱效,有很高的实用价值。