Production and recovery of oxygenated hydrocarbons by plural distillation

Claim 1

PROCESS FOR THE PRODUCTION OF OXYGENATED ORGANIC COMPOUNDS WHICH COMPRISES OXIDIZING PROPYLENE FEEDSTOCKS WITH MOLECULAR OXYGEN IN A SOLVENT SELECTED FROM THE GROUP CONSISTING OF FULLY ESTERIFIED POLYACYL ESTERS OF POLYHYDROXYALKANES, POLYHYDROXYCYCLOALKANES, POLYGLYCOLS AND MIXTURES THEREOF, WHEREIN SAID ESTERS CONTAIN FROM 1 TO 18 CARBON ATOMS LIN EACH ACYL MOIETY, AND FRIM 2 TO 18 CARBON ATOMS IN EACH ALKYLENE AND CYCLOALKYLENE MOIETY, UNDER TEMPERATURES AND PRESSURES SUFFICIENT TO CAUSE THE REACTION TO PROCEED IN THE LIQUID PHASE AND RECOVERING SAID OXYGENATED PRODUCTS BY: (A) DIRECTING AN EFFLUENT STREAM OF THE REACTION MIXTURE FROM A REACTION ZONE THROUGH A COMBINATION LETDOWN DISTILLATION ZONE COMPRISING A FLASHING ZONE FOLLOWED BY A STRIPPING ZONE, SAID FLASHING ZONE AND STRIPPING ZONE BEING MAINTAINED AT PRESSURES SUBSTANTIALLY LOWER THAN IN EACH PRECEDING ZONE AND AT TEMPERATURES NECESSARY TO SEPARATE SUBSTANTIALLY ALL OF THE LOW AND INTERMEDIATE BOILING PRODUCTS OVERHEAD AS GAS PHASE AND HIGHER BOILING COMPONENTS INCLUDING THE BULK OF THE SOLVENT AND POLYMERIC RESIDUE HAVING A BOILING POINT ABOVE THAT OF SAID SOLVENT WHICH ARE REMOVED AS BOTTOMS FROM SAIT STRIPPING ZONE, (B) PASSING SAID OVERHEAD GAS PHASE TO CONDENSING ZONES, FROM WHENCE UNCONDENSED GASES ARE DIRECTED TO AN ABSORBING ZONE INTO WHICH THE BOTTOMS STREAM FROM SAID STRIPPING ZONE IS ALSO PASSED TO ABSORB UNCONDENSED PROPYLENE, PROPANE AND MINOR AMOUNTS OF OXYGENATED COMPONENTS; REMOVING VENT GASES OVERHEAD FROM SAID ABSORBER, WHILE FEEDING THE BOTTOMS STREAM FROM SAID ABSORBING ZONE BACK TO SAID REACTION ZONE, (C) ADJUSTING REACTION CONDITIONS IN SUCH MANNER THAT AT STEADY STATE THE POLYMERIC RESIDUE CONTENT IN THE BOTTOMS STREAM FROM SAID ABSORBING ZONE GOING INTO SAID REACTION ZONE IS APPROXIMATELY EQUIVALENT TO THE POLYMERIC RESIDUE CONTENT IN SAID EFFLUENT STREAM FOR A PREDETERMINED PRODUCT DISTRIBUTION. (D) FEEDING A COMBINED STREAM OF CONDENSED LIQUIDS FROM SAID CONDENSING ZONES INTO A PRIMARY PRODUCTS DISTILLATION SPLITTING ZONE FROM WHICH AN OVERHEAD STREAM CONTAINING PROPYLENE AND PROPANE ARE REMOVED TO A DISTILLATION SPLITTER FOR THESE COMPONENTS, THE PROPANE BEING REMOVED AS BOTTOMS WHILE PROPYLENE IS REMOVED OVERHEAD AND RECYCLED TO SIAD REACTION ZONE, (E) DIRECTING A SIDESTREAM FROM SAID PRIMARY PRODUCTS DISTILLATION SPLITTING ZONE TO AN INTERMEDIATES REMOVAL DISTILLATION ZONE FROM WHICH A BOTTOMS STREAM CONTAINING METHYL ACETATE, ACETONE, METHANOL AND OTHER INTERMEDIATE BOILERS ARE REMOVED, (F) FEEDING THE OVERHEAD FROM SAID INTERMEDIATES REMOVAL DISTILLATION ZONE TO AN ATMOSPHERIC EXTRACTIVE DISTILLATION ZONE USING A HYDROCARBON SOLVENT BOILING ABOVE 67*C. AS EXTRACTURE SOLVENT AND FROM WHICH PROPYLENE OXIDE DISSOLVED IN SAID HYDROCARBON SOLVENT IS REMOVED AS BOTTOMS AND FED TO A DISTILLATION REFINING COLUMN WHEREIN PURIFIED PROPYLENE OXIDE IS RECOVERED OVERHEAD AND SAID HYDROCARBON IS REMOVED AS BOTTOMS AND RECYCLED TO SAID EXTRACTIVE DISTILLATION ZONE, (G) FEEDING THE OVERHEAD FROM SAID EXTRACTIVE DISTILLATION ZONE TO A METHYL FORMATE ACETALDEHYDE DISTILLATION SEPARATION ZONE WHEREIN METHYL FORMATE IS REMOVED AS BOTTOMS AND ACETALDEHYDE IS TAKEN OVERHEAD AND RECYCLED TO SAID REACTION ZONE, (H) FEEDING THE BOTTOMS FROM SAID PRIMARY PRODUCTS DISTILLATION SPLITTING ZONE IN STEP (D) TO AN ACID SOLVENT DISTILLATION SPLITTING ZONE WHEREIN SUBSTANTIALLY ALL HIGHER BOILING COMPONENTS ARE REMOVED AS BOTTOMS, AND ALL ACID VALUES, WATER AND INTERMEDIATE BOILERS ARE REMOVED OVERHEAD AND FED TO AN ACID-INTERMEDIATES DISTILLATION ZONE FROM WHICH THE INTERMEDIATES ARE RECOVERED OVERHEAD, WHILE DIRECTING THE BOTTOMS CONTAINING ACID VALVES AND WATER TO AN AZEOTROPIC DISTILLATION COLUMN USING BENZENE AS AN AZEOTROPE-FORMER FOR WATER AND FORMIC ACID. (I) REMOVING FROM SAID AZETROPIC DISTILLATION ZONE AN OVERHEAD STREAM CONTAINING A MIXTURE OF BENZENEWATER AND BENZENE-FORMIC ACID AZEOTROPES TO A CONDENSING ZONE WHEREIN BENZENE IS SEPARATED FROM WATER AND FORMIC ACID AND FEEDING THESE THREE COMPONENTS TO A COLLECTING ZONE IN WHICH BENZENE FORMS AN UPPER PHASE FROM WHICH BENZENE IS RETURNED TO SAID AZEOTROPIC DISTILLATION ZONE, WHILE WATER AND FORMIC ACID ARE REMOVED AS A LOWER PHASE, WHILE REMOVING FROM SAID AZEOTROPIC DISTILLATION ZONE A BOTTOMS STREAM CONTAINING ACETIC ACID TO A DISTILLATION REFINING ZONE WHEREIN PURIFIED ACETIC ACID IS RECOVERED OVERHEAD, (J) FEEDING THE BOTTOMS FROM SAID ACID- SOLVENT DISTILLATION SPLITTER IN STEP (H) CONTAINING MAJOR AMOUNTS OF SOLVENT FROM SAID REACTION ZONE, MINOR AMOUNTS OF PROPYLENE GLYCOL AND MONOESTERS THEREOF TO AN ESTER CONCENTRATION ZONE FROM WHICH SOME OF SAID SOLVENT SUBSTANTIALLY DEPLETED OF SAID PROPYLENE GLYCOL AND ITS MONOESTERS IS REMOVED AS BOTTOMS AND RECYCLED TO SAID REACTION ZONE, WHILE REMOVING AN OVERHEAD STREAM COMPRISED OF THE REST OF SAID SOLVENT NOW ENRICHED WITH SAID PROPYLENE GLYCOL AND ITS MONOESTERS, (K) FEEDING THE OVERHEAD FROM SAID ESTER CONCENTRATION ZONE TOGETHER WITH MONOCARBOXYLIC ACID VALUES TO AN ESTERIFICATION ZONE WHEREIN PROPYLENE GLYCOL AND ITS MONOESTERS ARE ESTERIFIED TO PROPYLENE GLYCOL DIESTERS, (L) FEEDING AN EFFLUENT STREAM FROM SAID ESTERIFICATION ZONE COMPRISING INCREASED AMOUNTS OF SAID DIESTERS, DECREASED AMOUNTS OF SAID ACID VALUES AND UNREACTED PROPLYLENE GLYCOL AND ITS MONOESTERS TO A SOLVENT DISTILLATION STRIPPING ZONE WHEREIN SAID ACID VALUES ARE REMOVED OVERHEAD AND RECYCLED TO SAID ACID-INTERMEDIATES DISTILLATION SEPARATION ZONE IN STEP (H) AND SAID DIESTERS AND ANY UNREACTED PROPYLENE GLYCOL AND ITS MONOESTERS ARE REMOVED AS BOTTOMS AND RECYCLED TO SAID ESTER CONCENTRATION ZONE, (M) FEEDING A FRACTION OF SAID SIDE STREAM IN STEP (E) CONTAINING PROPYLENE OXIDE AND OTHER OXYGENATED ORGANIC COMPONENTS HAVING BOILING POINTS BETWEEN THAT OF PROPYLENE OXIDE AND WATER TO A HYDROLYSIS ZONE WHEREIN PROPYLENE OXIDE IS HYDROLYZED TO PROPYLENE GLYCOL (S) WHICH IS REMOVED AS BOTTOMS FREE OF WATER, WHILE UNREACTED PROPYLENE OXIDE AND SAID OTHER OXYGENATED COMPONENTS ARE WITHDRAWN AS OVERHEAD PRODUCT FREE OF WATER AND REFLUXED TO A REGION OF SAID HYDROLYSIS ZONE BELOW WHICH SAID OTHER OXYGENATED COMPONENTS FROM A BARRIER BETWEEN OXYGENATED COMPONENTS FORM A BARRIER BETWEEN WATER OF HYDROLYSIS AND PROPYLENE OXIDE, AND (N) FEEDING A PORTION OF SAID OVERHEAD PRODUCT IN STEP (M) TO SAID SIDE STREAM GOING TO SAID INTERMEDIATES REMOVAL ZONE.