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 POLYHYDROXYLALKANES, POLYHYDROXYCYCLOALKANES, POLYGLYCOLS AND MIXTURES THEREOF, WHEREIN SAID ESTERS CONTAIN FROM 1 TO 18 CARBON ATOMS IN EACH ACYL MOIETY AND FROM 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 LET-DOWN 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 TEMPERATURE 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 SAID 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 THE CONDENSED PROPYLENE, PROPANE AND MINOR AMOUNTS OF OXYGENATED COMPONENTS; REMOVING VENT GASES OVERHEAD FROM SAID ABSORBED, WHILE FEEDING THE BOTTOMS STREAM FROM SAID ABSORBING ZONE BACK TO SAID REACTION ZONE, (C) ADJUSTING REACTION CONDITIONS IN SUCH MANNER THAT IS 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 SAID 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 EXTRACTIVE 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 INSTEP (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 ACIDS-INTERMEDIATES DISTILLATION ZONE FROM WHICH THE INTERMEDIATES ARE RECOVERED OVERHEAD, WHILE DIRECTING THE BOTTOMS CONTAINING ACID VALUES AND WATER TO AN AZETROPIC DISTILLATION COLUMN USING BENZENE AS AN AZEOTROPE-FORMER FOR WATER AND FORMIC ACID, (I) REMOVING FROM SAID AZEOTROPIC 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 IS 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 ARE 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 AND DECREASED AMOUNTS OF SAID ACID VALUES TO A SOLVENT STRIPPING DISTILLATION ZONE WHEREIN SAID ACID VALUES ARE REMOVED OVERHEAD AND RECYCLED TO SAID ACIDS-INTERMEDIATES DISTILLATION SEPARATION ZONE IS STEP (H) AND SAID DIESTERS ARE REMOVED AS BOTTOMS AND RECYCLED TO SAID ESTER CONCENTRATION ZONE.