Mechanism of Replacement of the Nitro Group and Fluorine Atom in meta-Substituted Nitrobenzenes by Phenols in the Presence of Potassium Carbonate
作者:I. A. Khalfina、V. M. Vlasov
DOI:10.1007/s11178-005-0280-1
日期:2005.7
The relative mobilities of the nitro group and fluorine atom in 1,3-dinitrobenzene and 1-fluoro-3-nitrobenzene by the action of phenols in the presence of potassium carbonate in dimethylformamide at 95–125°C were studied by the competing reaction method. The rate constant ratios k(NO2)/k(F) were correlated with the differences between the corresponding activation parameters (ΔΔH ≠ and ΔΔ S ≠). The greater mobility of the nitro group was found to be determined by the entropy control of the reactivity of arenes. The activation parameters (ΔH ≠ and ΔS ≠) were calculated, and the enthalpy-entropy compensation effect was revealed. The reaction mechanism is discussed.
采用竞争反应法研究了在二甲基甲酰胺中,于 95-125°C 下,在碳酸钾存在下,1,3-二硝基苯和 1-氟-3-硝基苯中的硝基和氟原子在苯酚作用下的相对迁移率。速率常数比 k(NO2)/k(F)与相应活化参数(ΔΔH≠和ΔΔS≠)之间的差异相关。研究发现,硝基的更大流动性是由羰基反应性的熵控制决定的。计算了活化参数(ΔH ≠ 和 ΔS ≠),并揭示了焓熵补偿效应。讨论了反应机理。