1,3-Propanediol (1,3-PD) was extd. from 3% aq. soln. with hexane after acetalization with MeCHO or EtMeCHO. The highest extn. efficiency (97%) was achieved for EtMeCHO in a molar excess of 2:1 at room temp., and for strongly acidic solns. with pH 0.5. The efficiency of MeCHO was twice smaller. The reactive extn. of the fermentation broths occurred to a slightly lower yield of 90% in two-step process. The sepd. acetal was hydrolyzed by reactive distn. to give 1,3-PD and the aldehyde recycled to the process.