由卤代芳硝基物制备卤代芳胺的综述

综述了由卤代芳硝基物还原制备卤代芳胺的三类方法,对三类还原方法的优缺点进行了对比和讨论,重点介绍了第三类制备卤代芳胺的还原方法-催化加氢还原法,最后介绍了催化加氢还原卤代芳香硝基物的新方法及新领域。     

还原法制备芳香胺的研究进展

介绍了芳硝基化合物还原制备芳香胺的主要方法以及各还原方法在芳硝基化合物还原中的应用。芳硝基化合物还原制备芳香胺的方法主要有催化加氢法、金属还原法、水合肼还原法、硫化碱还原法、电化学还原法、催化氢转移法、光催化还原法、葡萄糖还原法、酶催化还原法等。其中光催化还原法和还原酶还原法反应条件温和、符合有机化合物转化过程中所追求的环保"良性"与"绿色"的目标,具有很高的研究应用价值。     

还原法制备芳香胺的研究进展

介绍了芳硝基化合物还原制备芳香胺的主要方法以及各还原方法在芳硝基化合物还原中的应用。芳硝基化合物还原制备芳香胺的方法主要有催化加氢法、金属还原法、水合肼还原法、硫化碱还原法、电化学还原法、催化氢转移法、光催化还原法、葡萄糖还原法、酶催化还原法等。其中光催化还原法和还原酶还原法反应条件温和、符合有机化合物转化过程中所追求的环保"良性"与"绿色"的目标,具有很高的研究应用价值。     

硝基化合物还原制备芳香胺工艺研究进展

综述了还原芳香族硝基化合物制备芳胺的主要方法,包括催化加氢法、金属还原法、水合肼还原法、电化学还原法等.在对4种还原反应机理概述的基础上,分别介绍了其应用情况及各自的优缺点.其中水合肼还原法由于其具有反应收率高、产品纯度高及无污染等优点越来越受到人们的关注.     

芳硝基化合物的水合肼催化还原法

一、产品和技术简介： 芳硝基化合物的还原方法工业上常用的有催化加氢、铁粉还原、硫化碱还原等。其中催化加氢为清洁还原方法,但首先需有氢源,需在封闭的高压系统中反应,对安全防范要求较高,设备一次投资也高,常用于大吨位芳胺的生产;铁粉还原及硫化碱还原为非清洁还原,铁粉还原法排放含胺铁泥,硫化碱还原法排放大量对生态不利的含硫废水：而且铁粉还原法在还原硝基时将同时使反应物分子中的氰基.     

液相催化加氢法制取芳胺的研究进展

对近年来以硝基芳烃为原料,用液相催化加氢还原方法制取芳胺的应用及其进展进行了归纳总结。对液相催化加氢法的主要影响因素和工艺条件进行了探讨。说明了该项技术具有很好的推广应用前景。     

异丙醇还原芳硝基化合物制备芳胺

制备了氧化铁、氢氧化氧铁和氢氧化氧铁/C等催化剂,并考察了其对异丙醇还原芳硝基化合物制备芳胺的催化活性。结果表明氢氧化氧铁/C的活性最高。在适宜的条件下,芳硝基化合物10mmol,异丙醇15mL,氢氧化钾0.1g,氢氧化氧铁/C0.1g,回流反应一段时间,得到芳胺的收率为35%~53%。     

液相催化加氢还原生产芳胺

芳香族胺类是染料、农药、医药及塑料等工业的重要原料,它的生产方法主要有两大类型,即还原法与氨解法。目前国内由芳香族硝基化合物制取芳胺在工业生产上大都沿用在电解质存在下的铁屑还原法以及用硫化碱还原法,但更有前途的应是催化加氢还原法。催化加氢还原可以在气相或液相进行。若硝基物在高温下容易气化并保持稳定状态,可采用气相方法,但多数硝基物因沸点高难以气化,有的如硝     

选择性加氢还原制备芳胺催化剂的研究进展

本文综述了近年来选择性加氢还原制备芳胺催化剂的最新研究进展,总结出传统催化剂进行改性是提高催化剂选择性的直接和有效方法,对Au和Ag等新型催化剂的最新研究成果进行了介绍.     

水合肼法还原芳香硝基化合物制备芳胺的技术进展

综述了水合肼法还原芳香硝基化合物制备芳胺及其衍生物的近况,讨论了影响还原反应的主要因素和工艺条件,并展望了水合肼法制备芳胺工艺的应用前景和发展方向。     

Image formation of alkyl-pendent aromatic polyimide by photocoupling with aromatic ketones

Positive and negative photostructures are formed after the polyimide (PI) of 4,4′-biphthalic anhydride (BPA) and 4,4′-diamino-3,3′-dimethyldiphenylmethane (DADMDPM), PI(BPA/DADMDPM) is doped with Michler′s ketone (MK) and benzophenone (BP), respectively, and is subjected to UV light (400 ± 50 nm) irradiation and solvent development. The principle of positive feature formation is based on the photocoupling of MK with PI, which increases PI solubility and thus enables a positive pattern to be developed. The phenomenon of negative photopatterning results from intermacromolecular H-bonding between the carbonyl group of the imide ring and the hydroxy group which is formed in the photoinduced coupling reaction between BP and PI. Lithographic evaluation shows that the MK-doped positive-acting PI film cannot form useful patterns because UV wavelengths are strongly absorbed by MK, which limits the depth of photocoupling in the film. On the other hand, 2-μm-wide lines can be resolved in the BP-doped negative-acting 0.6-μm-thick PI film.     

Hydrogenation of aromatic aldehydes to aromatic hydrocarbons over Cu-HZSM-5 catalyst

With benzaldehyde as a model compound, the hydrogenation of aromatic aldehydes to aromatic hydrocarbons was investigated. Cu-HZSM-5 exhibited excellent catalytic performance for the reaction. The obtained catalysts were characterized by N₂ adsorption/desorption, N₂O chemisorptions, X-ray diffraction, NH₃-temperature programmed desorption and X-ray photoelectron spectroscopy. It was found that Cu⁰ active species exhibited poor activity for the hydrogenation of benzene ring, while the strong acidity of HZSM-5 accelerated the hydrogenation reaction via hydrogen spillover phenomenon and the C–O activation effect. In addition, the catalyst was proved to be effective for the hydrogenation of a series of aromatic aldehydes to corresponding aromatic hydrocarbons.     

芳香醇的合成

通过Cannizzaro反应,以芳香醛和甲醛为原料,合成系列芳香醇。研究了反应物的摩尔比、催化剂氢氧化钾的质量分数及用量、反应时间等因素对芳香醇收率的影响。在n(芳香醛)∶n(甲醛)=1.0∶1.5,质量分数40%KOH溶液的用量1.5 mL,室温下搅拌反应50 min的优化条件下,芳香醇的产率为73.4%~97.8%。     

Porous aromatic networks with amine linkers for adsorption of hydroxylated aromatic hydrocarbons

The porous covalent organic polymers (COPs) are valuable materials in various fields such as gas storage, adsorption or separation, luminescent detection, catalysis, and sensors. Two thermally stable COPs with aromatic skeleton linked by amine groups were prepared by Buchwald–Hartwig protocol. The COPs with respective Brunauer–Emmett–Teller surface area of 204 and 178 m²/g were employed for adsorption of hydroxylated aromatic hydrocarbons (HAHs) due to expected strong π–π stacking and hydrogen-bond interactions between COPs and HAH. In adsorption of phenol from water, COP₂ showed far better capacity than COP₁, silica, basic alumina, and macroporous resin (D101). In adsorption of 2-naphthol COP₁ and COP₂ displayed similar capacity, being 2.8, 5.4, and 7.4 times high as those for macroporous resin (D101), basic alumina, and silica, respectively. COP₁ and COP₂ are useful for efficient separation of 2-naphthol or other HAHs from waste water. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46919.     

Perfluoroalkylene-linked aromatic polymers

Polymers of the type (m-C₆H₄·(CF₂)_m·m-C₆H₄-X))n have been synthesised and their properties are reported. They include polyesters and polycarbonates, polysiloxanes, polyimides and poly-(1,3-phenylenehexafluoro-trimethylene. Preparation of the precursors was facilitated by the discovery of a direct fluoroalkylation process involving fluoroalkylcopper intermediates. In various instances, the effects of introducing m-phenylene-perfluoroalkylene units on the properties of these polymers, particularly their glass transition temperatures, are compared with the corresponding effects from m-phenylene ether units.     

Processable aromatic polyimides

Two similar polyimide systems were synthesized and characterized. The only structural difference was a sulfide linkage in the anhydride-derived portion of the first system vs. a sulfone linkage in the second. Their physical, mechanical, melt-flow and thermal properties, and their resistance to some of the more common solvents were determined. The flow properties of these polyimides indicate a potential for melt processability.     

The pyrolysis behaviors of ternary copolyimide derived from aromatic dianhydride and aromatic diisocyanates

A polyimide (PI) based on benzophenone‐3,3′,4,4′‐tetracarboxylic acid dianhydride, toluene diisocyanate (TDI), and 4,4′‐methylenebis (phenyl isocyanate) (MDI) has been synthesized via a one‐step polycondensation procedure. The resulting PI possessed excellent thermal stability with the glass transition temperature (T_g) 316°C, the 5% weight loss temperature (T_5%) in air and nitrogen 440.4°C and 448.0°C, respectively. The pyrolysis behaviors were investigated with dynamic thermogravimetric analysis (TGA), TGA coupled with Fourier transform infrared spectrometry (TGA–FTIR) and TGA coupled with mass spectrometry (TGA–MS) under air atmosphere. The results of TGA–FTIR and TGA–MS indicated that the main decomposition products were carbon dioxide (CO₂), carbonic oxide (CO), water (H₂O), ammonia (NH₃), nitric oxide (NO), hydrogen cyanide (HCN), benzene (C₆H₆), and compounds containing NH₂, C?N, N?C?O or phenyl groups. The activation energy (E_a) of the solid‐state process was estimated using Ozawa–Flynn–Wall (OFW) method which resulted to be 143.8 and 87.8 kJ/mol for the first and second stage. The pre‐exponential factor (A) and empirical order of decomposition (n) were determined by Friedman method. The activation energies of different mechanism models were calculated from Coats–Redfern method. Compared with the activation energy values obtained from the OFW method, the actual reaction followed a random nucleation mechanism with the integral form g(α) = ?ln(1 ? α). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40163.