关键词: ¹H NMR, 线性关系, 混合溶剂, 快速交换平衡

Abstract: This article deals with the ¹H NMR of N, N-dimethyl formamide (DMF) in a mixed solvent of benzene and carbon tetrachloride. It has been found that the chemical shifts of the resonance absorption lines of the two methyl groups in N, N-dimethyl formamide (DMF) and that of benzene in the mixed solvent move upficld gradually, as the mole fraction of benzene in the mixed solvent increases. And the rates of upficld shifts of the resonance absorption lines of the two methyl groups are different. △δ of α-CH₃ is larger than that of β-CH₃.The chemical shifts of the two methyl groups in DMF and benzene in the mixed solvent can be schemed with a linear equation (δ=A + BX), where X is the mole fraction of benzene in the mixed solvent. The correlation coefficients R are approximately equal to-1.

Key words: ¹H NMR, Linear relation, Mixed solvent, Fast exchange equilibrium