Exchange reaction of linear acetals with ethylene glycol by C-13 NMR spectroscopy

Reaction of linear acetals RCH(OR')(2) (R = H, CH3, C2H5; R' = CH3, C2H5, C 3H7) with ethylene glycol in a neutral medium at 25 degrees C was studied b y C-13 NMR spectroscopy. The equilibrium compositions of the reaction mixtu res and their dependence on the reactant molar ratio were determined. It is shown that under the experimental conditions used dimethoxymethane fails t o react with ethylene glycol, and the reactions of the other acetals yield much cyclic acetals, 1,3-dioxolanes. The reaction of 2-methyl-1,3-dioxolane with methanol gives the same products as the reaction of 1,1-dimethoxyetha ne with ethylene glycol.