Enhancement of corrosion protection effect in poly(2,3-dimethylaniline) via the formation of nanofiber materials by introducing p-phenylenediamine

Poly(2,3-dimethylaniline) (P(2,3-DMA)) nanofiber was prepared by introducing p-phenylenediamine as an initiator into the reaction mixture solution. The P(2,3-DMA) nanofiber was characterized by X-ray diffraction, Fourier transformation infrared spectroscopy and scanning electron microscopy. The results showed that the introduction of p-phenylenediamine favors one-dimensional growth of P(2,3-DMA). In order to compare the anticorrosion performance of P(2,3-DMA) nanofiber with that of poly(2,3-dimethylaniline) prepared without adding p-phenylenediamine (C-P(2,3-DMA)), epoxy resin coating containing P(2,3-DMA) nanofiber and C-P(2,3-DMA) was painted on mild steel, respectively. The anticorrosion property of the as-prepared nanofiber coating was evaluated by open circuit potential, tafel polarization curves and impedance spectroscopy in 3.5 wt% NaCl aqueous solution. Experimental results indicated that P(2,3-DMA) nanofiber had higher anticorrosion property compared with C-P(2,3-DMA). Hence, the morphology could be responsible for better anti-corrosion performances.     

对硝基苯胺水相加氢合成对苯二胺

以对硝基苯胺为原料,水为溶剂,考察了水相中负载型镍催化剂催化对硝基苯胺加氢还原的反应性能,并开展了中试实验。考察了反应温度、压力、保温时间、对硝基苯胺浓度、废水套用等因素对催化加氢反应性能的影响。实验结果表明,产品对苯二胺质量分数较高,催化剂和水可循环使用。得到较佳的工艺条件为:温度110℃,保温时间1 h,压力2.0 MPa,搅拌转速800 r/min,起始催化剂用量10%(以对硝基苯胺的质量为基准,下同),催化剂损耗0.2%(以起始添加催化剂的质量为基准)。在该工艺条件下,对苯二胺产率达99.5%以上。废水套用后排放废水量很少,且对催化剂催化活性、产品质量等没有影响。     

FIA光度法自动监测对苯二胺的合成

酸性介质中，对苯二胺与苯胺在过硫酸钾存在时生成蓝色染料．依据此反应和FIA区域采样技术，建立了自动监测对硝基苯胺合成对苯二胺的FIA光度法．方法简单、快速、采样少、选择性高，线性范围和相对标准偏差分别是0～40mg／mL和0．875％．     

对苯二胺的化学研究进展

较为详细的对对苯二胺的制备、性质及应用等方面进行了综述.归纳了对苯二胺的各种制备方法,并讨论了其工业化的优劣.同时介绍了对苯二胺发生的一些典型反应,最后总结了对苯二胺及其衍生物在精细化工和高分子材料等方面的应用.     

Electrochemical synthesis of belt-like polyaniline network on p-phenylenediamine functionalized glassy carbon electrode and its use for the direct electrochemistry of horse heart cytochrome c

Three-dimension (3D) belt-like polyaniline (PAN) network has been prepared via electrochemical polymerization of aniline on p-phenylenediamine (PDA) functionalized glassy carbon electrode (GCE) using a three-step electrochemical deposition procedure. PDA was covalently binded on GCE via the formation of carbon-nitrogen bond between amine cation radical and the aromatic moiety of GCE surface using electrochemical oxidation procedure. X-ray photo-electron spectroscopy (XPS) and cyclic voltammetry have been performed to characterize the attachment of PDA on GCE. The images of scanning electron microscope (SEM) show that the 3D belt-like PAN network is uniform. The width and thickness of the PAN belt varies in the range of 1.5-5.5 μm and 0.1-0.8 μm, respectively. The distance between the belt-contacts ranges from 2.5 to 15 μm. The 3D belt-like PAN network modified GCE (PAN-PDA/GCE) exhibits an improved electro-activity of PAN at an extended pH up to 7.0. The PAN-PDA/GCE not only immobilizes but also leads to a direct electrochemical behavior of cytochrome c (Cyt c). The immobilized Cyt c maintains its activity, showing a surface-controlled electrode process with the electron-transfer rate constant (k_s) of 14.8 s⁻¹ and electron-transfer coefficient (α) of 0.48, and could be used for the electrocatalytic reduction of hydrogen peroxide (H₂O₂).     

PTFE中空纤维膜萃取对苯二胺工艺研究

以硫酸溶液为萃取剂,采用PTFE中空纤维膜萃取料液中的对苯二胺,考察了料液相对苯二胺的初始浓度、料液相初始pH、料液相与萃取相流量、萃取剂的初始浓度对对苯二胺萃取率(η)的影响。结果表明,随着料液初始浓度增大,η增大,当对苯二胺浓度0.8 g/L时,η减小,但膜通量基本不变,即存在一个最大膜通量,此时对苯二胺浓度变化对传质无影响;对苯二胺料液的pH增大,η增大;萃取相硫酸浓度增大,η增大。另外,温度升高有利于膜萃取。     

对苯二胺邻磺酸的合成

该文介绍了一种对苯二胺邻磺酸的新的合成方法,以对苯二胺为原料,20％发烟硫酸为磺化剂,磺化得到对苯二胺邻磺酸。