Abstract Changes in chemical shifts of olefinic protons in a number of α, β-and α, β, γ, δ- unsaturated carboxylic acids caused by ionization of the COOH group were investigated. The ionization shifts of α-H-atoms are− 0.09 to 0.07 ppm, those of β-H-atoms are 0.32− 0.47 ppm. The ionization shifts of δ-H-atoms are substantially larger than those of γ-H-atoms. The ionization shifts can be used for immediate determination of the esterification site in ...
