Process for separating water from aqueous methanol mixtures

Claim 1

IN A PROCESS FOR SEPARATING WATER FROM A WATER METHANOL MIXTURE OF PRODUCE AMETHANOL PRODUCT WITH A REDUCED WATER CONTENT, THE STEPS WHICH COMPRISE INTRODUCING A CRUDE AQUEOUS METHANOL MIXTURE INTO A DISTILLATION COLUMN, DISTILLING THE AQUEOUS METHANOL MIXTURE IN SAID DISTILLATION COLUMN TO PROVIDE A METHANOL-WATER VAPOR, INTRODUCING INTO SAID COLUMN A WATER-INSOLUBLE NORMALLY LIQID HYDROCARBON WHICH FORMS AN AZEOTROPE WITH THE WATER WHICH AZEOTROPE HAS A BOILING POINT LOWER THAN THE BOILING POINT OF METHANOL, SAID WATER-INSOLUBLE HYDROCARBON BEING CONTACTED WITH THE VAPOROUS METHANOLWATER MIXTURE IN MOLAR AMOUNTS OF ABOUT 1 TO 3 TIMES THE MOLAR AMOUNT OF WATER PRESENT IN THE METHANOL-WATER MIXTURE IN THE COLUMN AT THE HEIGHT OF WATER-INSOLUBLE HYDROCARBON INTRODUCTION, SAID HYDROCARBON HAVING A BOILING POINT SUBSTANTIALLY NO HIGHER THAN THE BOILING POINT OF METHANOL IN THE MIXTURE, AND RECOVERING AN ESSENTIALLY ANHYDROUS METHANOL PRODUCT WITH A REDUCED WATER CONTENT AT A HEIGHT IN THE COLUMN BELOW THE HEIGHT WHERE WATER-INSOLUBLE HYDROCARBON IS INTROUDCED AND ABOVE THE POINT OF CRUDE AQUEOUS METHANOL MIXTURE INTRODUCTION, SAID HYDROCARBON BEING INTRODUCED AT A HEIGHT IN THE COLUMN WHERE THE VAPOR CONTAINS A MINIMUM AMOUNT OF WATER, SAID HEIGHT OF MINIMUM AMOUNT OF WATER BEING BETWEEN THE POINT OF SAID ESSENTIALLY ANHYDROUS METHANOL PRODUCT RECOVERY AND THE TOP OF THE COLUMN, AND REMOVING ESSENTIALLY WATER FROM THE BOTTOM OF THE COLUMN AT A POINT BELOW THE POINT OF SAID ESSENTIALLY ANHYDROUS METHANOL PRODUCT RECOVERY.