Method for the mutual separation of acrylonitrile, acetonitrile, and propionitrile from aqueous solutions

Claim 1

A METHOD FOR THE MUTUAL SEPARATION OF ACRYLONITRILE, ACETONITRILE AND PROPIONITRILE FROM AN AQUEOUS SOLUTION THEREOF WHICH COMPRISES FEEDING SAID AQUEOUS SOLUTION INTO AN ACETONITRILE EXTRACTOR, INTRODUCING INTO SAID EXTRACTOR A SELECTIVE SOLVENT FOR ACETONITRILE COMPRISED OF AN AQUEOUS SOLUTION SUBSTANTIALLY SATURATED WITH ACRYLONITRILE AND PROPIONITRILE, WITHDRAWING FROM SAID ACETONITRILE AND PROPIONITRILE, WITHDRAWING FROM SAID ACETONITRILE SOLUTION CONTAINING LESS THAN ABOUT 15 PERCENT ACRYLONITRILE AND PROPIONITRILE, INTRODUCING SAID IMPURE AQUEOUS ACETONITRILE SOLUTION INTO AN EXTRACTIVE DISTILLATION COLUMN, INTRODUCING WATER INTO THE TOP OF SAID EXTRACTIVE DISTILLATION COLUMN AS SOLVENT, WITHDRAWING AN AQUEOUS SOLUTION OF SUBSTANTIALLY PURE ACETONITRILE FROM THE BOTTOM OF SAID EXTRACTIVE DISTILLATION COLUMN, REMOVING A MIXTURE OF ACRYLONITRILE, PROPIONITRILE AND LESS THAN ABOUT 15 PERCENT WATER OVERHEAD FROM SAID EXTRACTIVE DISTILLATION COLUMN AND FEEDING SAID MIXTURE TO SAID ACETONITRILE EXTRACTOR AS SOLVENT, REMOVING FROM SAID ACETONITRILE EXTRACTOR A SECOND FRACTION COMPRISING A MIXTURE OF ACRYLONITRILE, PROPIONITRILE AND LESS THAN ABOUT 15 PERCENT WATER, INTRODUCING SAID LATTER MIXTURE INTO AN AZEOTROPIC DISTILLATION COLUMN, REMOVING OVERHEAD FROM SAID AZEOTROPIC COLUMN THE WATER AZEOTROPES OF ACRYLONITRILE AND PROPIONITRILE, SEPARATING SAID WATER AZEOTROPES OF ACRYLONITRILE AND PROPIONITRILE INTO AN AQUEOUS PHASE SATURATED WITH ACRYLONITRILE AND PROPIONITRILE AND AN ORGANIC PHASE, FEEDING SAID AQUEOUS PHASE TO SAID ACETONITRILE EXTRACTOR AS SOLVENT, RETURNING SAID ORGANIC PHASE TO SAID AZEOTROPIC DISTILLATION COLUMN AS REFLUX, WITHDRAWING A SUBSTANTIALLY ANHYDROUS MIXTURE OF ACRYLONITRILE AND PROPIONITRILE FROM THE BOTTOM OF SAID AZEOTROPIC DISTILLATION COLUMN, INTRODUCING SAID SUBSTANTIALLY ANHYDROUS MIXTURE INTO A FRACTIONAL DISTILLATION COLUMN AND RECOVERING SUBSTANTIALLY PURE ANHYDROUS ACRYLONITRILE AND PROPIONITRILE THEREFROM.

Claim 2

A METHOD FOR THE MUTUAL SEPARATION OF ACRYLONITRILE, ACETONITRILE AND PROPIONITRILE FROM AN AQUEOUS SOLUTION THEREOF WHICH COMPRISES FEEDING SAID AQUEOUS SOLUTION INTO AN ACETONITRILE EXTRACTOR, INTRODUCING INTO SAID EXTRACTOR A SELECTIVE SOLVENT FOR ACETONITRILE COMPRISED OF AN AQUEOUS SOLUTION SUBSTANTIALLY SATURATED WITH ACRYLONITRILE AND PROPIONITRILE, WITHDRAWING FROM SAID ACETONITRILE AND PROPIONITRILE, WITHDRAWING FROM SAID ACETONITRILE SOLUTION CONTAINING LESS THAN ABOUT 15 PERCENT ACRYLONITRILE AND PROPIONITRILE, INTRODUCING SAID IMPURE AQUEOUS ACETONITRILE SOLUTION INTO AN EXTRACTIVE DISTILLATION COLUMN, INTRODUCING WATER INTO THE TOP OF SAID EXTRACTIVE DISTILLATION COLUMN AS SOLVENT, WITHDRAWING AN AQUEOUS SOLUTION OF SUBSTANTIALLY PURE ACETONITRILE FROM THE BOTTOM OF SAID EXTRACTIVE DISTILLATION COLUMN, REMOVING A MIXTURE OF ACRYLONITRILE, PROPIONITRILE AND LESS THAN ABOUT 15 PERCENT WATER OVERHEAD FROM SAID EXTRACTIVE DISTILLATION COLUMN AND FEEDING SAID MIXTURE TO SAID ACETONITRILE EXTRACTOR AS SOLVENT, REMOVING FROM SAID ACETONITRILE EXTRACTOR A SECOND FRACTION COMPRISING A MIXTURE OF ACRYLONITRILE, PROPIONITRILE AND LESS THAN ABOUT 15 PERCENT WATER, INTRODUCING SAID LATTER MIXTURE INTO AN AZEOTROPIC DISTILLATION COLUMN, REMOVING OVERHEAD FROM SAID AZEOTROPIC COLUMN THE WATER AZEOTROPES OF ACRYLONITRILE AND PROPIONITRILE, SEPARATING SAID WATER AZEOTROPES OF ACRYLONITRILE AND PROPIONITRILE INTO AN AQUEOUS PHASE SATURATED WITH ACRYLONITRILE AND PROPIONITRILE AND AN ORGANIC PHASE, FEEDING SAID AQUEOUS PHASE TO SAID ACETONITRILE EXTRACTOR AS SOLVENT, RETURNING SAID ORGANIC PHASE TO SAID AZEOTROPIC DISTILLATION COLUMN AS REFLUX, WITHDRAWING A SUBSTANTIALLY ANHYDROUS MIXTURE OF ACRYLONITRILE AND PROPIONITRILE FROM THE BOTTOM OF SAID AZEOTROPIC DISTILLATION COLUMN, INTRODUCING SAID SUBSTANTIALLY ANHYDROUS MIXTURE INTO A FRACTIONAL DISTILLATION COLUMN AND RECOVERING SUBSTANTIALLY PURE ANHYDROUS ACRYLONITRILE AND PROPIONITRILE THEREFROM.