An acidity scale of 1,3-dialkylimidazolium salts in dimethyl sulfoxide solution

被引：174

作者：

Chu, Yuan ^{[1
]}

Deng, Hui ^{[1
]}

Cheng, Jin-Pei ^{[1
]}

机构：

[1] Nankai Univ, State Key Lab Elementoorgan, Dept Chem, Tianjin 300071, Peoples R China

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2007年 / 72卷 / 20期

关键词：

D O I：

10.1021/jo070973i

中图分类号：

O62 [有机化学];

学科分类号：

070303 [有机化学]; 081704 [应用化学];

摘要：

[GRAPHICS] Equilibrium acidities of 16 1,3-dialkylimidazolium-type ionic liquid (IL) molecules (1-16) were systematically measured by the overlapping indicator method at 25 degrees C in dimethyl sulfoxide (DMSO) solution. The pK(a) values were observed to range from 23.4 for IL 12 to 19.7 for IL 6 (Tables 1 and 2), responding mainly to structural variations on the cation moiety. Excellent agreement between the spectrophotometrically determined pK(a) and that derived from NMR titration for 1,3,4,5-tetramethylimidazolium bis(trifluoromethanesulfonyl)imide (12) and the close match of the obtained pK values with the reported data in literature provide credence to the acidity measurements of the present work. The substituent effects at the imidazolium ring and the effects of counterions on the acidities of ionic liquids are discussed.

引用

页码：7790 / 7793

页数：4

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