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1.
4-氨基吡啶是一种重要的精细化工产品, 为探讨其电化学合成过程的反应机理, 采用循环伏安法、库仑电解等方法对强酸性条件下4-硝基吡啶-1-氧化物的电化学行为进行了研究. 结果表明: 4-硝基吡啶-1-氧化物在铂电极上主要经历电化学-化学-电化学(ECE)还原历程, 并生成4-羟胺吡啶-1-氧化物; 对铜电极而言, 当电位高于-0.65 V时主要经历ECE还原历程, 并生成4-羟胺吡啶-1-氧化物; 当电位低于-0.85 V时经历ECE还原历程生成的4-羟胺吡啶-1-氧化物, 可发生进一步4e-还原, 并生成4-氨基吡啶. 相似文献
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利用二氧化硫脲制备对氨基苯酚 总被引:3,自引:0,他引:3
利用二氧化硫脲制备对氨基苯酚顾尚香姚卡玲(兰州大学化学系甘肃730000)对氨基苯酚的制备方法之一是用铁粉在盐酸存在下生成的新生态氢将对硝基苯酚中的硝基还原为氨基,产率约80%左右,但铁泥的处理非常麻烦;另一方法是用苯酚为原料先制备出对亚硝基苯酚,然... 相似文献
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采用磁控溅射物理气相沉积技术在金属镍基体上制备碳化钨纳米晶薄膜. 薄膜具有纳米晶结构, 由粒径为20~35 nm的晶粒构成, 晶粒分布均匀, 晶相结构为非化学计量比的碳化钨(WC1-x). 采用电化学方法研究硝基甲烷在纳米晶碳化钨薄膜电极上的电化学还原性能和反应机理. 实验结果表明, 碳化钨薄膜电极对硝基甲烷电化学还原反应具有较好的催化性能, 当电极电位为-0.89 V(vs.SCE)时, 硝基甲烷还原为甲基羟胺的电流达14.9 mA/cm2, 其反应表观活化能为12.3 kJ/mol. 硝基甲烷在碳化钨薄膜电极上经过一步不可逆的电化学反应还原成甲基羟胺, 其控制步骤是电极反应的电荷传递过程. 相似文献
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(一)葡萄糖或转化糖在碱性溶液中能把硝基酚类、亚硝基酚类及对磺酸苯偶氮酚类化合物还原成为相应的氨基酚类化合物。得到正面结果的有:阾硝基苯酚、对硝基苯酚、4-硝基2-甲基苯酚、2,6-二氯-4-硝基苯酚、对亚硝基苯酚、4-亚硝基-2-甲基苯酚、α-亚硝基-β-萘酚、对磺酸苯偶氮苯酚、橙Ⅱ等九种化合物。结果可称满意。(二)间硝基苯酚与2,4-二硝基苯酚在上述条件下,得不到相应的氨基酚类化合物。 相似文献
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利用电聚合法和脉冲沉积技术制备了纳米银/聚多巴胺修饰的玻碳电极. 通过循环伏安法和示差脉冲伏安法研究了该修饰电极上对硝基苯酚的电化学行为; 讨论了扫描速度和支持电解质等条件对对硝基苯酚在修饰电极上催化还原的影响. 结果表明, 对硝基苯酚的示差脉冲峰电流在4×10-5~3×10-4 mol/L范围内呈良好的线性关系. 相似文献
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阴阳极协同作用下对硝基苯酚的电催化降解 总被引:1,自引:0,他引:1
利用线性扫描伏安法和恒电流电解法研究了Ti/PbO2电极对于对硝基苯酚(PNP)降解的电催化活性,通过对阳极过程和阴极过程中对硝基苯酚及其降解中间产物的液相色谱测定,研究了阴阳极协同作用下对硝基苯酚电催化降解的历程。 结果表明,Ti/PbO2电极能够有效地电催化降解水溶液中的对硝基苯酚,在35 ℃,初始浓度为1 mmol/L的对硝基苯酚水溶液,恒定电流密度40×10-3 A/cm2,电解240 min,对硝基苯酚转化率为98.6%。 对硝基苯酚电催化氧化降解要经历生成对苯二酚、邻苯二酚、对苯醌、丁烯二酸和草酸,最终变成二氧化碳和水的反应历程,其中对苯二酚为第一步反应的主产物,对苯醌转化为丁烯二酸和丁烯二酸转化为草酸这两步反应是阳极氧化过程的速率控制步骤。 对硝基苯酚在阴极上发生还原反应,还原产物为对氨基苯酚(PAM)。 在无隔膜电解槽中,由于阴极还原产物对氨基苯酚很容易到阳极上发生氧化反应,阴阳两极产生协同作用,因而加速了对硝基苯酚的降解反应。 相似文献
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3-硝基苯甲酸在DMSO介质中的电化学还原 总被引:2,自引:0,他引:2
本文用循环伏安法、控制电位电解和ESR方法结合, 研究了3-硝基苯甲酸(3-NBA)在DMSO介质中, Pt电极上的电化学还原过程。结果表明, 3-硝基苯甲酸通过三电子还原生成一种亚硝基自由基。观测到了自由基ESR谱的超精细结构。确定了ESR模拟谱的参数: a_1~N=10.91G, a_2~H=1.12G, a_4~H=a_6~H=3.38G, a_5~H=3.96G. 估算了自由基衰变速度常数k=4.814×10~(-2)s~(-1). 相似文献
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制备了用掺杂铕(Ⅲ)离子的类普鲁士蓝膜修饰的玻碳电极,并研究了2,4,6-三硝基苯酚在此修饰电极上的电化学行为.试验结果表明:与裸玻碳电极相比,2,4,6-三硝基苯酚在此修饰电极上的还原峰电流显著提高,还原电位大大降低,且工作曲线的线性范围明显增宽.在此基础上提出了一种高灵敏度直接测定2,4,6-三硝基苯酚的伏安测定法.在优化的条件下,测得特征还原峰的电流值与2,4,6-三硝基苯酚浓度在4.0×10-5~2.0× 10-3mol·L-及2.0× 101~8.0×10-6mol·L-1范围内呈线性关系,方法的检出限(3σ)为6.0×10×-8mo·L×-1.以黄河水样作为基体,用标准加入法做回收试验,测得回收率在97.7%~103.3%之间. 相似文献
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The following rate equation was found for the nitrosation of phenol by nitrous acid to p-nitrosophenol in aqueous solution at constant ionic strength:
$$\frac{{d(p - C_6 H_4 OHNO)}}{{dt}} = k[C_6 H_5 OH][HNO_2 ].$$ 相似文献
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Two-phase additivity rule for radiation yields of p-nitrophenol, m-nitrophenol and p-nitrosophenol has been demonstrated. The data of partial radiation yields indicated that the nitrobenzene phase is by several times more reactive than a water phase /H2O, 3M HNO3 or 1.5M H2SO4/ in respect of nitrophenols formation. 相似文献
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本文研究了二(对硝基苯氧基)-甲烷或对硝基苯酚在浓硫酸的存在下与过量多聚甲醛的反应,合成得到含两个和三个苯环的对硝基苯酚亚甲基桥齐聚物的苯并二噁环衍生物。柱层析分出四个纯品,经IR,~1H NMR,MS分析鉴定,其中三个为新化合物。这类化合物作为合成子可用于硝基取代的杯芳烃或长链亚甲基桥齐聚物的收敛性分步合成。 相似文献
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本文研究了二(对硝基苯氧基)-甲烷或对硝基苯酚在浓硫酸的存在下与过量多聚甲醛的反应, 合成得到含两个和三个苯环的对硝基苯酚亚甲基桥齐聚物的苯并二恶环衍生物. 柱层析分出四个纯品, 经IR, ^1H NMR, MS 分析鉴定,其中三个为新化合物. 这类化合物作为合成子可用于硝基取代的杯芳烃或长链亚甲基桥齐聚物的收敛性分步合成 . 相似文献
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A method for the biological monitoring of human exposure to aromatic hydrocarbons, nitrocompounds, amines and phenols has been developed. Phenol, cresols, p-aminophenol, p-nitrophenol and their glucorono- or sulpho-conjugates, were quantified by HPLC; 4-chlorphenol was added as internal standard. After enzymatic hydrolysis, the free compounds were extracted with an organic solvent and analyzed by an isocratic HPLC Perkin Elmer system at ambient temperature and at a flow-rate of 1 ml/min. The column was a reversed-phase Pecosphere 3 x 3 C18 Perkin Elmer; the mobile phase was a 30:70:0.1 (v/v/v) methanol-water-orthophosphoric acid mixture and the chromatogram was monitored at 215 nm. Identification was based on retention time and quantification was performed by automatic peak height determination, corrected for the internal standard. The recovery was ca. 95% for phenol and cresols; 90% for p-nitrophenol; 85% for p-aminophenol; the coefficients of variance were less than 6% within analysis (n = 20) and less than 10% between analysis (n = 20). The detection limits, at a signal/noise ratio of 2, were 0.5 mg/l for phenol and cresols and 1 mg/l for p-aminophenol and p-nitrophenol. 相似文献
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Yasuhiro Aoki 《Tetrahedron》2005,61(22):5219-5222
Synthesis of phenol and cyclohexanone in one pot was examined by means of the NHPI-catalyzed aerobic oxidation of cyclohexylbenzene. The aerobic oxidation of cyclohexylbenzene catalyzed by NHPI followed by treatment with sulfuric acid afforded phenol and cyclohexanone in good selectivities. Thus, the reaction of cyclohexylbenzene under atmospheric dioxygen (1 atm) by NHPI at 100 °C for 3 h followed by treatment with 0.3 M sulfuric acid at room temperature for 2 h resulted in phenol and cyclohexanone in 96 and 91% selectivity, respectively, at 25% conversion. This method was successfully extended to the one-pot synthesis of 4-hydroxyacetophenone and cyclohexanone. 相似文献
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R. Mihalache I. Peleanu I. Meghea A. Tudorache 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):B133-138
The present paper deals with the competitive adsorption on activated carbon of three aqueous bi-solute systems (phenol/p-nitrophenol,
phenol/p-chlorphenol, p-nitrophenol/p-chlorphenol) and of the tri-solute system phenol/p-nitrophenol/p-chlorphenol. In this
context two experimental methods to evaluate the equilibrium characteristics for the adsorption of phenols on powdered activated
carbon were used. The competitive adsorption data were statistically fitted on four models: the Langmuir competitive model,
the Freundlich-Langmuir competitive model, and the Fritz-Schlunder model, the last one in two particular cases for the monosolute
representation. The prediction for all models, excepting the Fritz-Schlunder model, were performed using only single-solute
data, while the parameters for the Fritz-Schlunder model were obtained using both single and multi-solute data. 相似文献
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LI Xiaotao Pan Bingcai Pan Bingjun Zhang Weimin Meng Fanwei Chen Jinlong Zhang Quanxing . State Key Laboratory of Pollution Control Resources Reuse School of the Environment Nanjing University Nanjing China . Department of Science Technology State Environmental Protection Agency Beijing China 《Chinese Journal of Reactive Polymers》2005,(Z1)
1. INTRODUCTION Phenolic compounds are pollutants encountered frequently in water system. Some of them, such as phenol and p-nitrophenol, have been listed as priority pollutants in many countries. How to remove them completely from the polluted water is of significant concern to environmental scientists. Up to now many technologies such as biodegradation, oxidation and adsorption are available to remove phenolic compounds from the receiving water [1~4]. In the past two decadesphenol sorpt… 相似文献
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LI Xiaotao Pan Bingcai Pan Bingjun Zhang Weimin Meng Fanwei Chen Jinlong Zhang Quanxing 《反应性高分子(英文版)》2005,14(1):44-51
X-ray photoelectron spectroscopy (XPS ) was adopted to elucidate sorption mechanism of phenol and p-nitrophenol onto a weakly anion exchanger D301. The distribution of specific forms of tertiary amino group on D301 was obtained and effect of free tertiary amino group on phenol sorption onto D301 was discussed. The result indicated that the percent of the protonated tertiary amine group on polymeric matrix was much lower than the reference compound N,N-dimethylbenzylamine at an identical pH value in solution due to the much lower activity degree of hydrogen ion in inner resin phase than in the external solution. Less free amino group on D301 results in less sorption capacity of phenol and p-nitrophenol in an acidic solution. Under the experimental conditions both phenol sorption onto D301 can be explained as solid extraction and the distribution coefficient varies linearly with the content of free amino group on D301. 相似文献