1HNMR spectra of the title compounds have been measured as the function of the mole fraction of benzene in the mixture solvent of benzene and CC14. As the mole fraction of benzene increases, the chemical shifts (δ) of two methyl groups in a molecule and of benzene gradually move upfield. The upfield shifts of different methyl groups in a molecule are not equal to one another. The Δδ of β-CH3is larger than that of α-CH3. Thus, the two lines appear to coalesce at a certain concentration and to cross over with the increment of the proportion of benzene. All of the chemical shifts can be related with a linear equation (δ=A+BX). Where, X is the mole fraction of benzene in the mixture solvent. The correlation coefficients R are approximately equal to 1.