Gündüz T, Kiliç E, Cakirer O
Department of Chemistry, Faculty of Science, University of Ankara, Ankara, Turkey.
Talanta. 1996 May;43(5):771-6. doi: 10.1016/0039-9140(96)01856-5.
Thirteen aliphatic and four aromatic amines, namely diethylamine, triethylamine, n-propylamine, di-n-propylamine, tri-n-butylamine, isopropylamine, di-isopropylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, aniline, N,N-dimethylaniline, 2-nitroaniline and 4-nitroaniline were titrated thermometrically with nitrosyl perchlorate in acetonitrile solvent. All the aliphatic amines gave very well-shaped thermometric titration curves. The calculated recovery values of the amines were very good. In comparison, the aromatic amines, aniline and N,N-dimethylaniline gave rather well-shaped titration curves, but the recovery values were fairly low. 2-Nitro- and 4-nitro anilines gave no thermometric response at all. The heats of reaction of the amines with nitrosyl perchlorate are rather high. However, the average heat of reaction of the aromatic amines is approximately two-thirds that of the average heat of the aliphatic amines. To support this method all the amines were also titrated potentiometrically and very similar results to those obtained with the thermometric method are seen. The nitrosyl ion is a Lewis acid, strong enough to titrate quantitatively aliphatic amines in acetonitrile solvent, but not strong enough to titrate aromatic amines at the required level in the same solvent.
用高氯酸亚硝酰在乙腈溶剂中对13种脂肪族胺和4种芳香族胺进行了温度滴定，这13种脂肪族胺分别是二乙胺、三乙胺、正丙胺、二正丙胺、三正丁胺、异丙胺、二异丙胺、正丁胺、二正丁胺、三正丁胺、异丁胺、仲丁胺、叔丁胺，4种芳香族胺分别是苯胺、N,N-二甲基苯胺、2-硝基苯胺和4-硝基苯胺。所有脂肪族胺都给出了形状很好的温度滴定曲线。胺的计算回收率非常好。相比之下，芳香族胺苯胺和N,N-二甲基苯胺给出的滴定曲线形状较好，但回收率相当低。2-硝基苯胺和4-硝基苯胺根本没有温度响应。胺与高氯酸亚硝酰的反应热相当高。然而，芳香族胺的平均反应热约为脂肪族胺平均反应热的三分之二。为了支持该方法，还对所有胺进行了电位滴定，得到了与温度滴定法非常相似的结果。亚硝酰离子是一种路易斯酸，其强度足以在乙腈溶剂中对脂肪族胺进行定量滴定，但强度不足以在同一溶剂中按所需水平滴定芳香族胺。
