论文部分内容阅读
前文报道了各种甲氧基萘用三甲硅基氯磺酸酯在非极性溶剂中进行的磺化反应。本文研究了四种卤代苯和六种卤代萘用三氧化硫在非极性溶剂中进行的磺化反应。卤代芳香化合物用氯磺酸,浓硫酸及发烟硫酸进行的磺化反应已有报道。在芳香化合物的亲电取代反应中,卤素的定位效应取决于以下两个因素。首先,负的诱导效应体现为F>Cl>Br>I,且对邻位的影响远大于对位的影响。而正的共轭效应亦体现为F>Cl>Br>I,对对位的影响最大。单取代卤苯在浓硫酸中进行磺化反应,几乎专一地发生在4—位上。说明尽管卤素降低了芳香环上的电子云密度,但仍为邻对位定位基。三氧化硫(SO_3)是最剧烈的磺化剂,溶于非极性溶剂二氯甲烷中,既减少了付反应,又可在室温下进行高效率的磺化反应。
The sulfonation of various methoxynaphthalenes with non-polar solvents using trimethylsilyl chlorosulfonate has been reported previously. In this paper, four kinds of halogenated benzene and six halogenated naphthalene sulfur trioxide in a non-polar solvent sulfonation reaction. Sulfonation of halogenated aromatic compounds with chlorosulfonic acid, concentrated sulfuric acid and oleum has been reported. In the electrophilic substitution reaction of aromatic compounds, the positioning effect of halogen depends on the following two factors. First of all, the negative induction effect is reflected as F> Cl> Br> I, and the impact on the ortho-position is much greater than that on the para-position. The positive conjugate effect is also reflected as F> Cl> Br> I, the greatest impact on the alignment. Monosubstituted halobenzenes are sulfonated in concentrated sulfuric acid and occur almost exclusively in the 4-position. This shows that although halogen reduces the density of electron cloud on the aromatic ring, it is still ortho-para positioning. Sulfur trioxide (SO 3) is the most severe sulfonating agent dissolved in methylene chloride, a nonpolar solvent, which not only reduces the pay-off reaction but also efficiently sulfonates at room temperature.