The disclosure relates to methods for separating mixtures of polyols, in particular mixtures of two of more different vicinal diols having close boiling points, thus making them difficult or impossible to separate using conventional distillation techniques. The polyol mixture is reacted with an aldehyde or ketone acetalization agent to form one or more acetals as corresponding acetalization reaction products. The acetalization reaction products are more easily separable either from each other (such as via distillation) or from an unreacted vicinal diol (such as via extraction, settling, or other phase separation). After separation, hydrolysis is performed on the acetalization reaction products to recover the vicinal diols as separate, purified components. The methods provide cost-effective processes for separating different polyols originally formed in admixture.