Abstract: 1,3-Propanediol produced in a known manner by catalytic hydrogenation of 3-hydroxypropionaldehyde (HPA) obtainable from acrolein has a high residual carbonyl content and leads to problems in the production of poly(1,3-propylene glycol terephthalate). Disclosed is a process for producing 1,3-propanediol having a residual carbonyl content, expressed as propionaldehyde, below 500 ppm and generally below 100 ppm produced in the presence of a fixed-bed or suspension hydrogenation catalyst under an H.sub.2 pressure of 5 to 300 bar providing the hydrogenation is carried out at 30.degree. to 80.degree. C. to an HPA conversion of 50 to 95% and is then continued at 100.degree. to 180.degree. C. to an HPA conversion of substantially 100%.

Abstract: The hydration of acrolein in the presence of a chelate-forming ion exchange resin based on polystyrene/divinyl benzene as catalyst and on the subsequent hydrogenation of the reaction mixture freed of the non-reacted acrolein and containing 3-hydroxypropionaldehyde is disclosed. As a result of using chelate-forming ion exchangers with anchor groups of the formula ##STR1## in which Z=H, C.sub.1 -C.sub.6 -alkyl, --CH.sub.2 --CH(CH.sub.3)--Y' or --(CH.sub.2).sub.o --Y' and Y and/or Y'=--COOH, --OH, pyridyl or --P(O)(CH.sub.2 OH)OH, the hydration occurs at lower temperatures with a greater space-time yield and especially a greater selectivity than when using previously known ion exchangers. Resins with methylene imino diacetic acid anchor groups in the H form or partially doped with alkali-, alkaline-earth or earth-metal ions are especially suitable.

Abstract: A method for preparing 1,3-propanediol is disclosed which comprises the hydration of acrolein in the presence of an acidic cation exchanger resin and the hydrogenation of the 3-hydroxypropionaldehyde obtained in the first stage. The volume-time yield was able to be increased in the hydration stage by using a cation exchanger resin with phosphonic acid groups, preferably a cation exchanger with chelating aminophosphonic acid groups. The hydrogenation catalyst can be repeatedly reused without appreciable loss of activity.