二甲基甲酰胺的变温付立叶变换红外光谱研究

Fourier Transform Infrared Spectra of Dimethylformamide at Variable Temperatures

DMF是一种具有优异性能的常用溶剂。根据FT—IR的高分辨率和高灵敏度的特点,研究了液体DMF的20—120℃的变温红外光谱,不同浓度的CCl_(4)溶液光谱和气体光谱。结果表明在液体DMF中存在着聚合分子,它们是以分子中醛基的C—H键与另一分子的羰基生成C—H…O式氢键而相互作用的。这种以C—H健与O所形成的氢键,已有报导的实例很少。

In the previous report we studied the FTIR spectra and normal coordinate analysis of dimethylformamide (DMF), an important solvent having many desirable properties. In order to understand the nature of interaction between DMF molecules in the vapor, liquid and solution stales, we have taken the advantages of the high resolving power and sensitivity of FTIR and studied the spectra of liquid DMF in the temperature range between 20° to 120℃ at 5° intervals and the effect of concentration on the spectra of DMF in CCl_(4) solution. It has been found that the liquid DMF exists in dimeric form through the formation of an unusual hydrogen bond between C-H…O, and in CCl_(4) solution, equilibrium exists between the dimeric and monomeric forms of DMF, the position of equilibrium is dependent upon the concentration.