分子筛型PAN-ACF制备及表面结构的XPS研究

以聚丙烯腈基活性炭纤维（PAN ACF）为原料,首次采用液相浸渍结合空气氧化的方 法,在较为温和的条件下改变原料的表面结构和孔隙结构,制备出具有分离N2/O2性能的分子 筛型PAN ACF.采用TGA DTA、电子天平及XPS技术分析表征了分子筛型PAN ACF的吸附性能 和表面结构.结果表明:浸渍煤焦油后的PAN ACF在100～400 ℃之间失重缓慢,是煤焦油中苯 环及杂环类化合物与纤维表面氧化接枝的过程;经350 ℃浸渍空气氧化ACF对N2/O2吸附量及 选择性均得到了显著提高,选择系数达到5.6;浸渍煤焦油的PAN ACF表面具有一定量的羟基 、醚基、羰基和羧基等含氧官能团,氧化过程中各类官能团含量发生改变,类石墨碳含量随浸 渍浓度增加而增大;浸渍氧化再炭化的结果使PAN ACF对N2/O2吸附选择性得到明显提高.     

PAN基活性炭纤维床层上有机溶剂蒸汽的穿透特性

本文考察了PAN基活性炭纤维（ACF）床层对低浓度有机溶剂蒸汽的吸附行为，并应用了Yoon—Nelson理论，发现穿透曲线可用改进的方程式来表达，得到了吸附剂ACF2的吸附常数及三氯乙烯、甲苯的总吸附传质系数。     

催化CVD调变PAN-ACF微结构研究

首次采用催化气相沉积法（CVD），以异丙醇为溶剂将催化剂[Ni(NO3)2.6H2O]有效地分散在PAN－ACF较大的微孔上，使其成为积炭的活性位，从而将ACF的孔径调控在分子筛孔径效应范围内，以液氮为吸附质，测定了样品吸附等温线，采用H－K及DFT法计算孔结构，用XRD及SEM表征ACF的显微结构，并对该沉积进行了解释。     

活性炭纤维的微孔结构水吸附

测定了两种活性炭纤维（ACF）的氮气、水吸附等温线和XPS,研究了ACF的微孔结构和表面性质,用αs图分析氮吸附等温线获得了ACF的比表面积、微孔容量和微孔径。XPS表明在ACF表面存在多种不同结合状态的氧。水在ACF上的吸附等温线呈V型,具有很大的脱附滞后环。水通过与ACF表面的氧形成氢键发生吸附。ACF表面的初始吸附点多,则在低、中压时的水吸附量就大。     

ZIF-8/改性聚丙烯腈电纺纳米纤维的制备及其高效去除水中孔雀石绿

通过原位生长方法，将最常见的金属有机骨架（MOFs）——沸石咪唑酯骨架材料（ZIF‐8）固定到羧甲基化聚丙烯腈静电纺丝纳米纤维（PAN‐COOH NFs）表面，得到ZIF‐8/PAN‐COOH NFs。通过扫描电子显微镜（SEM）、能量色散光谱（EDS）、X射线粉末衍射（XRD）和傅里叶变换红外光谱（FTIR）对合成的ZIF‐8/PAN‐COOH NFs形貌和结构进行表征，并深入研究ZIF‐8/PAN‐COOHNFs从废水中去除孔雀石绿（MG）的性能。研究发现： ZIF‐8/PAN‐COOH NFs对MG的吸附符合拟二级动力学方程，吸附过程可采用Langmuir等温线模型拟合，其对MG的最大吸附容量可达3 604 mg·g^-1。此外，ZIF‐8/PAN‐COOH NFs在染料吸附实验中表现出良好的分离功能和重复利用性。     

用密度函数理论和杜比宁方程研究活性炭纤维多段充填机理

本文运用密度函数理论（DFT）和杜比宁方程分别对活性炭纤维（ACF）的氮吸附等温线进行解析，经过两种解析结果的对比，验证了ACF上的多段充填机理，提出与各吸附段相对应的孔径范围，并讨论了各吸附段的吸附分压。在此基础上，比较了不同原料ACF的不同孔径结构对其多段吸附的决定作用。     

用FTIR和XPS研究ACF的表面结构

采用红外光谱（FTIR）及X光电子能谱（XPS），系统分析了纤维碳化各阶段的结构、不同程度活化的ACF的结构以及低温氧化后和热处理后ACF的结构，提出了ACF表面结构模型。     

多孔炭物理化学结构及其表征

以碳为基本骨架的多孔炭因具有丰富的孔隙结构和表面化学宫能团,在吸附分离、催化、电子等领域应用广泛.在阐述多孔炭孔结构（物理结构）和表面化学宫能团（化学结构）基础上,重点介绍了透射电镜等可直接观察多孔炭孔结构的表征方法及Dubinin微孔充填理论、平均场密度泛函理论、吸附法、压汞法等表征多孔炭孔结构的主要理论及方法,以及...     

改性活性炭纤维可见光催化联合脱硫脱硝的研究

利用水合肼还原法制备的TiO₂/Cu₂O复合光催化剂对活性炭纤维(ACF)进行改性,利用SEM、XPS、BET以及XRD对其进行表征,研究改性后ACF的性质及其脱硫脱硝效果。研究表明,TiO₂/Cu₂O同时改性后的ACF表面孔径减小,但表面石墨碳和羰基(C=O)官能团增加,增强了ACF对NO和SO₂的吸附能力,从而提高了脱硫脱硝的效率,该催化剂在40℃、可见光的催化下脱硫效率达90%,脱硝效率达60%。     

活性炭纤维电吸附重金属及磺胺甲恶唑性能研究

使用盐酸对吸附剂活性炭纤维(activated carbon fiber,ACF)进行改性,通过SEM、BET和FTIR对改性前后的ACF形貌及结构进行系统表征发现,改性后ACF较改性前表面杂质减少且沟壑更加明显,比表面积提高22%,微孔体积增加5%,含氧官能团(C-O和C=O)明显增多.以水中重金属离子(Zn(II)及Cr(VI))和抗生素磺胺甲恶唑(Sulfamethoxazole,SMX)为目标污染物,研究改性后ACF对目标污染物的吸附(静吸附和电吸附)性能,考察了浓度、pH、外加电压对吸附的影响.结果表明,ACF用量为5 g,电压为1.2 V,Zn(II)、Cr(VI)及SMX浓度均为10mg·L~(-1),Zn(II)溶液pH为5时,ACF吸附水中Zn(II)的最大吸附量为9.25 mg·g~(-1),是静吸附条件的2.15倍;Cr(VI)溶液pH为4时,ACF吸附Cr(VI)的最大吸附量为8.86 mg·g~(-1),是静吸附条件的1.96倍;SMX溶液pH为6时,ACF吸附SMX的最大吸附量为8.32 mg·g~(-1),是静吸附条件的1.84倍.ACF吸附Zn(II)、Cr(VI)及SMX的动力学曲线均符合准二级动力学模型,吸附过程为化学吸附.Freundlich等温模型能更好地描述ACF对Zn(II)、Cr(VI)及SMX的吸附特性,其吸附形式为多分子层吸附.ACF通过电极反接方式进行循环再生,脱附速率快且脱附效果明显,经4次循环再生后,ACF对Zn(II)、Cr(VI)及SMX的去除率均在90%以上.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.     

Catalyst free,visible-light promoted photoaddition reactions between C60 and N-trimethylsilylmethyl-substituted tertiary amines for synthesis of aminomethyl-1,2-dihydrofullerenes

An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C₆₀ and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C₆₀, followed by SET from the amine to the triplet excited state of C₆₀. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C₆₀ radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared.     

Highly efficient and stereoselective cycloaddition of nitrones to indolyl- and pyrrolylacrylates

The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities.     

Transition metal-free direct amination of benzoxazoles using formamides as nitrogen sources

A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields.     

l-Proline-catalyzed five-component domino reaction leading to multifunctionalized 1,2,3,4-tetrahydropyridines

Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl₃-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction.     

Exploring the scope of the Gewald reaction: Expansion to a four-component process

An efficient four-component reaction was developed to take advantage of the reactivity of the 2-aminothiophene-3-carbonitrile functionality, which is obtained during the classical three-component Gewald reaction. Various α-methylene bearing ketones were reacted with malononitrile, elemental sulfur, and aryl/heteroarylnitrile derivatives in t-BuOH/NaOH to afford 2-arylthieno[2,3-d]pyrimidin-4-amines in high yields. Preliminary studies revealed the photophysical properties of the products and their potential for use as metal sensors.