Recovery of isopropyl acetate and ethanol from an isopropyl acetate ethanol and water-containing stream

Abstract

High purity isopropyl acetate and ethanol are recovered from a process stream containing isopropyl acetate, ethanol and water by a multiple step process including extracting substantially all of the ethanol from the stream using water as a solvent, stripping the extract stream to remove substantially all of the remaining isopropyl acetate as an overhead recycle stream, which is combined with the fresh feed stream prior to the extraction step, fractionating the ethanol-rich stripping column bottoms stream to produce a ethanol-water azeotropic overhead stream and using a portion of the fractionating column bottoms stream as the solvent for the extraction step.

What is claimed is: 
     
       1. A process for the recovery of isopropyl acetate and ethanol from a feed mixture comprising isopropyl acetate, ethanol and water comprising: a) introducing said feed mixture into a solvent extractor in which the solvent comprises water and recovering a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) introducing said ethanol-rich extract stream to a first fractional distillation zone and producing an isopropyl acetate-rich stream and a substantially isopropyl acetate-free intermediate stream,   c) recycling said isopropyl acetate-rich stream to said solvent extractor,   d) introducing said substantially isopropyl acetate-free intermediate stream to a second fractional distillation zone and recovering a substantially azeotropic ethanol-water stream and a high purity water stream, and   e) recycling said high purity water stream to said solvent extractor as solvent.   
     
     
       2. The process of claim 1 wherein said feed mixture comprises about 15 to about 90 weight percent isopropyl acetate and about 10 to about 70 weight percent ethanol. 
     
     
       3. The process of claim 1 carried out on a continuous basis. 
     
     
       4. The process of claim 1 wherein said isopropyl acetate-rich stream and said feed mixture are combined prior to introduction into said solvent extractor. 
     
     
       5. The process of claim 1 carried out on a batch basis. 
     
     
       6. The process of claim 5 wherein said feed mixture and said isopropyl acetate-rich stream are separately introduced into said solvent extractor. 
     
     
       7. The process of claim 1 wherein a portion of the isopropyl acetate-rich stream is returned to the top of the first fractional distillation zone as reflux. 
     
     
       8. The process of claim 1 wherein a portion of the substantially azeotropic ethanol-water stream is returned to the top of the second fractional distillation zone as reflux. 
     
     
       9. A process for the recovery of isopropyl acetate and ethanol from a feed mixture comprising isopropyl acetate, ethanol and water comprising: a) extracting said feed mixture in an extraction zone with water as the extraction solvent to recover a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) stripping said ethanol-rich extract stream to produce an isopropyl acetate-rich stream and a substantially isopropyl acetate-free stream,   c) recycling said isopropyl acetate-rich stream to said extraction zone,   d) distilling said substantially isopropyl acetate-free stream to recover an ethanol-water stream and a high purity water stream, and   e) recycling said high purity water stream as extraction solvent.   
     
     
       10. A process for the recovery of high purity isopropyl acetate from a feed mixture comprising isopropyl acetate, ethanol and water comprising: a) introducing said feed mixture into a solvent extractor in which the solvent comprises water and recovering a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) introducing said ethanol-rich extract stream to a stripping zone and recovering an isopropyl acetate-rich stream and a substantially isopropyl acetate-free steam, and   c) recycling said isopropyl acetate-rich stream to said solvent extractor.   
     
     
       11. A process for the recovery of high purity isopropyl acetate from a feed mixture comprising isopropyl acetate, ethanol and water comprising: a) extracting said feed mixture in an extraction zone with water as the extraction solvent to recover a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) distilling said ethanol-rich extract stream to recover an isopropyl acetate-rich stream and a substantially isopropyl acetate free stream, and   c) recycling said isopropyl acetate-rich stream to said extraction zone.   
     
     
       12. A process for the recovery of isopropyl acetate and ethanol from a feed mixture comprising isopropyl acetate, ethanol and water comprising: a) contacting said feed mixture with water in an extraction zone to recover an isopropyl acetate-rich, substantially ethanol-free raffinate stream and an ethanol-rich extract stream,   b) fractionally distilling said ethanol-rich extract stream to produce an isopropyl acetate-rich stream, an aqueous ethanol-rich, substantially isopropyl acetate-free stream and a high purity water stream, and   c) recycling said isopropyl acetate-rich stream to said extraction zone.   
     
     
       13. The process of claim 12 wherein said fractionally distilling is carried out in single unit. 
     
     
       14. The process of claim 12 wherein said fractionally distilling is carried out in two units. .Iadd. 
     
     
       15.  A process for the recovery of isopropyl acetate and ethanol from a mixture comprising isopropyl acetate, ethanol and water comprising: a) introducing said mixture into a solvent extractor in which the solvent comprises water and recovering a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream, and   b) introducing said ethanol-rich extract stream into a stripping zone and recovering an isopropyl acetate-rich stream and a substantially isopropyl acetate-free stream. .Iaddend. .Iadd.   
     
     
       16.  A process for the recovery of high purity isopropyl acetate from a mixture comprising isopropyl acetate, ethanol and water comprising: a) extracting said mixture in an extraction zone with water as the extraction solvent to recover a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream, and   b) distilling said ethanol-rich extract stream to recover an isopropyl acetate-rich stream and a substantially isopropyl acetate-free stream. .Iaddend. .Iadd.17. A process for the recovery of isopropyl acetate and ethanol from a mixture comprising isopropyl acetate, ethanol and water comprising:   a) contacting said mixture with water in an extraction zone to recover an isopropyl acetate-rich, substantially ethanol-free raffinate stream and an ethanol-rich extract stream, and   b) fractionally distilling said ethanol-rich extract stream to produce an isopropyl acetate-rich stream, an aqueous ethanol-rich, substantially isopropyl acetate-free stream and a high purity water stream. .Iaddend. .Iadd.18. A process for the recovery of isopropyl acetate and ethanol from a mixture comprising isopropyl acetate, ethanol and water comprising:   a) introducing said mixture into a solvent extractor in which the solvent comprises water and recovering a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) introducing said ethanol-rich stream to a first fractional distillation zone and producing an isopropyl acetate-rich stream and a substantially isopropyl acetate-free intermediate stream, and   c) introducing said substantially isopropyl acetate-free intermediate stream to a second fractional distillation zone and recovering a substantially azeotropic ethanol-water stream and a high purity water   
     
     
        stream. .Iaddend. .Iadd.19.  A process for the recovery of isopropyl acetate and ethanol from a mixture comprising isopropyl acetate, ethanol and water comprising: a) extracting said mixture in an extraction zone with water as the extraction solvent to recover a high purity isopropyl acetate raffinate stream and an ethanol-rich extract stream,   b) stripping said ethanol-rich extract stream to produce an isopropyl acetate-rich stream and a substantially isopropyl acetate-free stream, and   c) distilling said substantially isopropyl acetate-free stream to recover an ethanol-water stream and a high purity water stream. .Iaddend. .Iadd.20. A process for the recovery of high purity isopropyl acetate from a mixture of isopropyl acetate, ethanol and water comprising:   a) introducing said mixture into a system comprising (1) a solvent extraction zone in which the solvent is water, and a raffinate comprising high purity isopropyl acetate and an extract comprising an ethanol-rich stream are produced; and (2) a fractional distillation zone in which an isopropyl acetate-rich fraction and a substantially isopropyl acetate-free fraction are produced;   b) introducing at least part of said extract into said fractional distillation zone;   c) introducing at least part of said isopropyl acetate-rich fraction into said extraction zone; and   d) withdrawing raffinate and substantially isopropyl acetate-free fraction   
     
     
        from said system. .Iaddend. .Iadd.21.  The process of claim 20, wherein said mixture is initially introduced into said solvent extraction zone. 
     
     
        .Iaddend. .Iadd.22.  The process of claim 20, wherein all of said isopropyl acetate-rich fraction is recycled to said extraction zone. 
     
     
        .Iaddend. .Iadd.23.  A method of recovering high purity isopropyl acetate from a mixture of isopropyl acetate, ethanol and water comprising: a) processing said mixture at least once through a system comprising (1) a solvent extraction zone in which a raffinate comprising high purity isopropyl acetate and an extract comprising an aqueous ethanol-rich stream are produced, and (2) a fractional distillation zone in which an isopropyl acetate-rich fraction and a substantially isopropyl acetate-free fraction are produced; and   b) withdrawing raffinate and substantially isopropyl acetate-free fraction from said system. .Iaddend.