PROCESS FOR PREPARING 1,3-PROPANEDIOL

摘要

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 the13-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. In particular the invention relates to such a process with improved heat recovery.