金属有机骨架HKUST-1及其衍生材料在催化中的应用进展

金属有机骨架材料(MOFs)作为异相催化剂受到了日益广泛的关注。在众多经典MOFs结构中,HKUST-1及其衍生材料是研究最多的类型之一。HKUST-1具有原料简单、易于合成、结构稳定、孔隙率高等多种优点,在异相催化领域中具有广阔的应用前景。已有多种HKUST-1相关材料被用作催化剂,包括HKUST-1本身、缺陷型结构、负载活性客体分子的复合型材料以及HKUST-1衍生的多孔碳纳米材料等。本文围绕HKUST-1作为催化剂的结构设计以及在不同催化反应中的应用展开总结与介绍,以期为相关MOFs材料的设计和催化研究提供一定参考。     

多孔有机骨架材料对顺式二醇化合物富集分离的研究进展

基于在碱性环境下硼酸能与顺式二醇化合物可逆共价结合形成稳定的五元或六元环酯,而在酸性环境下环酯开环释放顺式二醇化合物这一特性,设计合成高效、高选择性、高富集性能的硼亲和材料的研究备受关注。近年来,许多研究工作者合成了各种类型的硼亲和材料,应用于高选择性富集顺式二醇化合物。金属有机骨架(MOFs)和共价有机骨架(COFs)由于具有孔径可调、高孔隙率、高比表面积、骨架结构可调和化学及热稳定性良好等特点,被广泛应用于色谱分离和样品前处理领域。为赋予MOFs和COFs材料对顺式二醇化合物的富集选择性,各种不同结构和不同种类的硼酸修饰的MOFs和COFs被合成出来。该综述主要是对近几年来80余篇源于科学引文索引关于硼酸功能化MOFs和COFs的种类、合成方法及其应用文章的总结,包括“金属配体-片段共组装”“合成后修饰”和“自下而上”的硼酸功能化多孔材料的修饰策略,以及硼酸功能化MOFs和COFs的种类,介绍了其在化学分析和生物分析领域的发展概况和应用前景,客观评价了硼酸功能化MOFs和COFs的区别和优缺点。该文旨在让研究人员能够充分了解近几年硼酸功能化多孔有机骨架材料的研究现状、掌握合成思路和方法,为其应用提供一定的理论指导和技术支撑,为加快硼酸功能化多孔有机骨架材料的商业化脚步贡献绵薄之力。     

类水滑石催化合成聚(碳酸1,4-丁二醇)酯二醇

采用共沉淀法制备了镁铝类水滑石(Mg-Al-CO3LDH)、镁锌铝类水滑石(Mg-Zn-Al-CO3LDH)和锌铝类水滑石(Zn-Al-CO3LDH),并研究了它们在碳酸二苯酯(DPC)与1,4-丁二醇(1,4-BD)酯交换合成聚碳酸酯二醇(PCDL)反应中的催化活性。在常压反应阶段,以苯酚的产率表征催化剂的活性;在减压缩聚阶段,以产品的数均分子量Mn和羟基值来表征催化剂的活性。结果发现,Zn-Al LDH具有良好的催化活性。在优化反应条件下,获得了Mn和羟基值分别为1600和70.8mg KOH/g的PCDL。     

铈基介孔金属有机骨架固定化酶的构建及催化性能

金属有机骨架(MOF)材料由于其孔隙率高、比表面积大以及具有发达的内联通孔道结构等优点,可以作为优良的生物分子固定化载体。通过表面活性自组装策略制备了铈基介孔MOF(Ce-MOF-F),表征结果表明,该材料有大的比表面积和呈辐射状的介孔孔道结构。以其为载体、南极假丝酵母脂肪酶B(CALB)为模型酶,通过物理吸附法制备了生物催化剂CALB@Ce-MOF-F,对该固定化酶的酶载量和催化性能进行了研究。在优化条件下,CALB的负载量为162.0mg/g载体,水解活性为899.1U/g蛋白。与游离CALB相比,CALB@Ce-MOF-F表现出对高温、酸碱和有机溶剂等有更强的耐受性;将Ce-MOF-F用于多种酶的固定化,研究其作为载体的普适性,结果表明,介孔Ce-MOF-F对洋葱伯克氏菌脂肪酶(BCL)和漆酶有良好的固定效果,可以作为良好载体,并能对酶起到较好的保护作用。     

超临界流体中制备微孔和介孔结构金属有机框架负载Ru及其催化性能

以柠檬酸为螯合剂,十六烷基三甲基溴化胺为表面活性剂,通过ZrOCl2·8H2O 与对苯二甲酸 (H2BDC) 反应制备了同时具有微孔和介孔结构的Zr基金属有机骨架材料(Zr-MOF),并在超临界CO2-甲醇流体中将 Ru 负载于 Zr-MOF 上, 制备了 Ru@Zr-MOF催化剂,采用傅里叶变换红外光谱、X射线粉末衍射、透射电子显微镜、热重分析、N2吸附-脱附、X射线光电子能谱和电感耦合等离子体发射光谱对催化剂进行了表征,研究了该催化剂在苯及其同系物加氢反应中的催化性能. 结果表明,Ru纳米金属颗粒均匀地分散在Zr-MOF载体上,平均粒径约为2.3nm,在苯及其同系物的加氢反应中表现出很高的催化活性和稳定性.     

介孔分子筛Al-MCM-41制备及催化合成二芳基乙烷

以硅酸钠为硅源、硫酸铝为铝源、CTAB为模板剂,采用水热法合成了骨架负载型固体酸Al-MCM-41介孔分子筛催化剂,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和红外(IR)方法对其进行了表征,同时研究了该催化剂在二芳基乙烷合成反应中的催化性能. 考察了各种反应因素的影响,确定其最佳合成条件为:原料m(苯乙烯)∶m(二甲苯)=1∶7.5,催化剂用量为1%(总投料质量分数),反应时间为3 h,反应温度为140 ℃,产率可达87.1%,比传统催化剂浓硫酸提高了17%. 研究结果表明,该催化剂是替代液体酸合成二芳基乙烷的理想固体酸催化剂.     

有机或金属-有机二维纳米材料的制备与应用

对石墨烯等二维材料的研究进一步引发了人们对相似结构的其他有机、金属-有机二维层状纳米材料的浓厚兴趣. 这些二维材料由于其优异的化学可剪裁性而受到关注, 预期未来在电子器件、催化和小分子分离等方面具有广泛的用途. 这篇综述系统地介绍了目前制备有机基二维材料的自上而下和自下而上的两大类方法, 总结了有机基二维材料在生物识别、小分子分离和纯化以及电学方面的应用, 最后讨论了有机基二维材料目前在制备和性质改进方面面临的问题和未来可能发展的研究方向.     

基于H3PW12O40·xH2O和3，5-二氨基-1，2，4-三氮唑的POMOF的合成、表征及催化氧化碘离子性能

采用水热法合成了一例结构新颖且罕见的Keggin型多金属氧酸盐基金属有机骨架化合物,即[Cu₄(3,5 - dtrz)₄][PW^Ⅵ₉W^Ⅴ₃O₃₉]·H₂O (1),其中3,5-dtrz=3,5-二氨基-1,2,4-三氮唑,并通过单晶X射线衍射、傅里叶变换红外光谱、热重分析、粉末X射线衍射和元素分析进行了表征。单晶X射线衍射分析表明：化合物1属于单斜晶系,空间群为C2/c,不对称结构包含2个Cu⁺、2个3,5-datrz配体、0.5个Keggin型磷钨酸阴离子和1个水分子,除结晶水外各组分之间通过共价键连接成Keggin型多金属氧酸盐基金属有机骨架化合物。以化合物1为非均相催化剂,在温度为55℃时催化H₂O₂氧化碘离子反应。结果表明,1催化下的碘单质生成速率为6.11×10^-7 mol·L-1·s^-1,且重复使用次数达到6次时转化率仍能高达99.6%。     

尿素催化醇解合成长碳链脂肪族碳酸二酯

氧化锌;尿素催化醇解合成长碳链脂肪族碳酸二酯     

TS-1分子筛催化苯酚和草酸二甲酯合成草酸二苯酯

碳酸二苯酯;酯交换;TS-1分子筛催化苯酚和草酸二甲酯合成草酸二苯酯     

Synthesis of polycarbonate diol catalyzed by metal-organic framework Zn_4O[CO_2-C_6H_4-CO_2]_3

The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy.It was then used as the catalyst for the preparation of polycarbonate diol(PCDL) via the transesterification between diphenyl carbonate(DPC) and 1,6-hexandiol(1,6-HD).Its catalytic activity in the transesterification process is evaluated by the yield ...     

Mechanism of transesterification and cyclization of epoxy–polycarbonate blends catalyzed by quarternary ammonium salt

The reaction of oxirane with carbonate using quarternary ammonium salts as catalyst has been studied. Curing is caused by the transesterification reaction of the oxirane cycle with the carbonate group that proceeds by an “insertion” mechanism in the stoichiometric system. The ratio of the reactants is two oxirane groups to one carbonate group. In the nonstoichiometric system, the epoxide content is more than the stoichiometric quantity required. A cyclization reaction is followed by the transesterification reaction. To identify the finished products, a model reaction was proposed using diphenyl carbonate and phenyl glycidyl ether which results in the formation of 4-phenoxymethyl-1,3-dioxolane-2-one (PMD). The mechanism of forming the cyclic structure is assumed to proceed through the chain scission of the network in which the molecular chain crosslinked with carbonate group by a transesterification reaction. © 1996 John Wiley & Sons, Inc.     

Synthesis and phase behaviour of new biodegradable liquid crystalline polycarbonate derived from side chain cholesteryl derivative

A new cholesterol side-functionalised polycarbonate was synthesised through a coupling reaction between the terminal carboxyl group of the monomer 6-cholesteroxy-6-oxocaproic acid (COHA) and side hydroxyl group of the polycarbonate (PHTMC). The chemical structures of the intermediate compounds, monomers and polymers obtained in this study were characterised with FT-IR and ¹H NMR spectrum. Their phase behaviour and thermal stability were investigated using polarising optical microscopy, differential scanning calorimetry, X-ray diffraction and thermogravimetric analysis. The monomer COHA showed a cholesteric phase, while the corresponding cholesterol side-functionalised polycarbonate P(TMC-g-COHA) revealed a smectic A phase. This behaviour was attributed to an increased density of the mesogenic units in side chain and hence an ordered organisation into the mesophase. Furthermore, P(TMC-g-COHA) could exhibit a liquid crystalline state below body temperature (≈37°C). This fact indicated it could be used clinically as a self-assemble material with orientational-order mesophase. In addition, P(TMC-g-COHA) had a good thermal stability, the corresponding thermal decomposition temperature was 241°C.     

Chemoselective Oxidation of Alkenes by Metal-Organic Framework-Supported Copper Catalyst

Oxidation of alkenes to carbonyls or diols compounds is important in synthesizing fine chemicals and pharmaceutical intermediates. We report the synthesis and characterization of an aluminum metal-organic framework node-supported copper(II) chloride (DUT-5-CuCl), which is an efficient heterogeneous catalyst for the oxidation of alkenes using H₂O₂ as an oxidizing agent. Styrene and various substituted styrenes were transformed into the corresponding carbonyl compounds in excellent selectivity and yields. DUT-5-CuCl is tolerant with various functional groups and could be recycled and reused at least 5 times in the oxidation of α-methylstyrene. Unlike the oxidation of styrene derivatives, DUT-5-Cu catalyzed oxidation of aliphatic and cyclic alkenes produced 1,2-diols compounds selectively. The mechanism of the DUT-5-Cu catalyzed oxidation of styrene to benzaldehyde was investigated in detail by various experiments such as the determination of reaction intermediates and characterization of the catalyst after catalysis, and computational studies. This work highlights the importance of MOF-supported earth-abundant metal catalysts for oxidation reactions to produce fine chemicals.     

磁性金属-有机骨架材料的合成及其应用

磁性金属-有机骨架(magnetic metal-organic frameworks,MMOFs)材料是近年来兴起的新型纳米功能材料,它由MOFs材料和磁性材料组合而成,具有高选择性、良好分散性和可多次重复利用等优点,在环境、医学和生物学研究领域应用广泛。本文介绍了MMOFs材料的四种合成方法,包括嵌入法、叠层法、封装法和混合法,其中嵌入法是指将磁性颗粒材料镶嵌在MOFs表面,叠层法是将MOFs层覆盖和叠加生长在官能化磁性颗粒材料表面,封装法是MOFs材料围绕磁性颗粒在其周围生长并将其包埋起来,混合法是将MOFs和磁性颗粒物通过物理或化学作用发生聚合合成。MOFs与磁性颗粒材料结合形成的MMOFs,既保留了MOFs材料的结构与性能,又增添了颗粒材料的磁性,从而大大拓展了MOFs的应用范围。鉴于MMOFs可携带特定的物质释放于指定位置,容易从复杂基质中分离,并可通过外部磁性进行定位与收集等优势与特点,其在生物医药、环境样品预处理和催化等领域得到了广泛的应用。     

Synthesis of polycarbonate from dimethyl carbonate and bisphenol-a through a non-phosgene process

A novel nonphosgene process for producing bisphenol-A polycarbonate (PC) was developed through a transesterification between bisphenol-A (BPA) and dimethyl carbonate (DMC) and a melt-polycondensation of the resulting bisphenol-A bismethylcarbonate (1). The transesterification was carried out by heating bisphenol A in dimethylcarbonate in the presence of Lewis acid catalysts, removing the by-producing methanol using molecular shieves 4A. Among various catalysts, a combination of (Bu₂SnCl)₂O and dimethylaminopyridine gave the best results to produce 1 in 22% yield for 48 h. Using a larger amount of the molecular sieves further improved the yield to 80% in 120 h. The resulting 1 was heated under reduced pressure in the presence of titanium catalysts to produce PC in good yields. The resulting PC had high weight average molecular weight (M_w) of 75,000. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2087–2093, 1999     

Fabrication of mesoporous ZnO nanosheets from precursor templates grown in aqueous solutions

Mesoporous ZnO nanosheets were successfully prepared by pyrolytic transformation of zinc carbonate hydroxide hydrate, Zn₄CO₃(OH)₆·H₂O. The nanosheets were initially formed as assemblies on glass substrates during chemical bath deposition (CBD) in aqueous solutions of urea and zinc acetate dihydrate, zinc chloride, zinc nitrate hexahydrate, or zinc sulfate heptahydrate at 80°C. It was key to induce heterogeneous nucleation of Zn₄CO₃(OH)₆·H₂O by promoting a gradual hydrolysis reaction of urea and controlling the degree of supersaturation of zinc hydroxide species. Morphology of Zn₄CO₃(OH)₆·H₂O was largely influenced by the anions present in the CBD solutions. The Zn₄CO₃(OH)₆·H₂O nanosheets were transformed into wurtzite ZnO by heating at 300°C in air without losing the microstructural feature.     

Synthesis of linear polyformal and copoly(carbonate formal) from polycarbonate

A linear, high molecular weight polyformal is readily synthesized by direct transformation of commercially available polycarbonate. The reaction is best carried out in dibromomethane with 8.0 equiv. of potassium hydroxide pellets in the presence of a phase-transfer catalyst at 90–95°C. A random copoly(carbonate formal) can also be obtained simply by reducing the amount of potassium hydroxide used in the reaction. The molecular weight of the resulting polymer is governed by the starting polycarbonate.     

Synthesis and properties of novel aliphatic polycarbonate from carbon dioxide with 1,2-butylene oxide and ε-caprolactone

A new degradable aliphatic poly(butylene-co-e-caprolactone carbonate) (PBCL) was synthesized through the terpolymerization of carbon dioxide, 1,2-butylene oxide (BO) and e-caprolactone (CL), a polymer supported bimetallic complex (PBM) was used as a catalyst. The terpolymers prepared were characterized by FT-IR,1H NMR, 13C NMR, WXRD and DSC. The hydrolysis tests were carried out to appraise the degradability of the copolymers.