Patent ID: 6969779

Claim:
In a process for producing 1,3-propanediol where an aqueous solution of 3-hydroxypropanal is formed, the 3-hydroxypropanal is hydrogenated to form a crude 1,3-propanediol mixture comprising 1,3-propanediol, water, MW176 cyclic acetal, and high and low volatility materials, the crude 1,3-propanediol mixture is dried to produce a first overhead stream comprising water and a first distillate bottoms stream comprising 1,3-propanediol, MW176 cyclic acetal, and high and low volatility materials, and the first distillate bottoms stream is distilled to produce a second overhead stream comprising high volatility materials, a middle stream comprising 1,3-propanediol and MW176 acetal, and a second distillate bottoms stream comprising 1,3-propanediol and low volatility materials, the improvement which comprises contacting said crude 1,3-propanediol mixture, prior to drying thereof, with an acidic zeolite at about 40 to about 150Â° C. to convert the MW176 cyclic acetal to more volatile materials which can be easily separated from 1,3-propanediol by distillation.