Patent ID: 7416645

Claim:
A method for recovering acetone from a waste stream from an acetone purification stage, wherein said waste stream comprises mesityl oxide, said method comprising: i) separating said waste stream in a separating device into at least a first stream comprising mesityl oxide; ii) concentrating said mesityl oxide, thereby producing concentrated mesityl oxide stream; iii) recycling said concentrated mesityl oxide stream into said separating device; and iv) bringing said concentrated mesityl oxide stream into contact with a basic aqueous medium, or with an acidic catalyst in the presence of water, whereby mesityl oxide is at least partially hydrolyzed to acetone, wherein said waste stream further comprises one or more organic components having a boiling point higher than acetone, said method further comprising: a) continuously feeding said waste stream to a middle section of a first distillation column; b) separating said waste stream in said first distillation column into: b2) a side stream comprising mesityl oxide and said organic components, and b3) a bottom stream comprising said basic aqueous medium; c) continuously feeding said side stream b2) into a middle section of a second distillation column; d) separating said side stream b2) in said second distillation column into: d1) a top stream comprising acetone, d2) a side stream comprising mesityl oxide, and d3) a bottom stream comprising organic components having a boiling point higher than mesityl oxide; and e) continuously recycling side stream d2) to the first distillation column through an entry point that is below a removal point for said side stream b2).