Refining and concentrating crude unsaturated aldehydes

Claim 1

THE PROCESS FOR SEPARATING ACROLEIN IN A HIGH STATE OF PURITY FROM A MIXTURE COMPRISING ACROLEIN IN ADMIXTURE WITH PROPIONALDEHYDE AND ACETONE, WHICH COMPRISES EXTRACTIVELY DISTILLING SAID MIXTURE IN A FIRST DISTILLATION ZONE AT A MINIMUM PRESSURE OF ABOUT ATMOSPHERIC PRESSURE IN THE PRESENCE OF A SUFFICIENT AMOUNT OF WATER TO MAINTAIN SUBSTANTIALLY A SINGLE LIQUID PHASE IN SAID DISTILLATION ZONE, SEPARATING A VAPOR FRACTION COMPRISING PROPIONALDEHYDE FROM LIQUID BOTTOMS COMPRISING ACROLEIN AND ACETONE SUBSTANTIALLY FREE OF PROPIONALDEHYDE IN SAID FIRST DISTILLATION ZONE, EXTRACTIVELY DISTILLING LIQUID BOTTOMS SEPARATED IN SAID FIRST DISTILLATION ZONE IN A SECOND DISTILLATION ZONE AT A MAXIMUM PRESSURE OF SUBSTANTIALLY ATMOSPHERIC PRESSURE IN THE PRESENCE OF A SUFFICIENT AMOUNT OF WATER TO MAINTAIN SUBSTANTIALLY A SINGLE LIQUID PHASE IN SAID SECOND DISTILLATION ZONE, AND SEPARATING A VAPOR FRACTION CONSISTING ESSENTIALLY OF ACROLEIN FREE OF ANY SUBSTANTIAL AMOUNT OF PROPIONALDEHYDE AND ACETONE FROM A LIQUID FRACTION COMPRISING WATER AND ACETONE IN SAID SECOND DISTILLATION ZONE.