Abstract: The invention provides a process for preparing 1,3-alkanediols, such as 1,3-propanediol (PDO), from 3-hydroxyaldehydes, such as 3-hydroxypropanal (HPA), comprising providing a mixture of 3-hydroxyaldehydes in an organic solvent; extracting into an aqueous liquid a major portion of the 3-hydroxyaldehydes to provide an aqueous phase comprising 3-hydroxyaldehydes in greater concentration than the concentration of 3-hydroxyaldehydes in the 3-hydroxyaldehyde mixture, and an organic phase; separating the aqueous phase from the organic phase; contacting the aqueous phase with hydrogen in the presence of a hydrogenation catalyst to provide a hydrogenation product mixture comprising 1,3-alkanediols and water; separating water from the 1,3-alkanediols using a multi-effect evaporation scheme; recycling water containing about 50 wt % or less 1,3-propanediol based upon the total amount of 1,3-propanediol and water to the extraction stage; and recovering 1,3-alkanediols.

Abstract: The invention provides a process for preparing 1,3-alkanediols, such as 1,3-propanediol (PDO), from 3-hydroxyaldehydes, such as 3-hydroxypropanal (HPA), comprising providing a mixture of 3-hydroxyaldehydes in an organic solvent; extracting into an aqueous liquid a major portion of the 3-hydroxyaldehydes to provide an aqueous phase comprising 3-hydroxyaldehydes in greater concentration than the concentration of 3-hydroxyaldehydes in the 3-hydroxyaldehyde mixture, and an organic phase; separating the aqueous phase from the organic phase; contacting the aqueous phase with hydrogen in the presence of a hydrogenation catalyst to provide a hydrogenation product mixture comprising 1,3-alkanediols and water; separating water from the 1,3-alkanediols using a multi-effect evaporation scheme; recycling water containing about 50 wt % or less 1,3-propanediol based upon the total amount of 1,3-propanediol and water to the extraction stage; and recovering 1,3-alkanediols.