Recovery of acetic acid from dilute aqueous streams formed during a carbonylation process
AssigneeHoechst Celanese Corporation
InventorsMark O. Scates, Steven E. Parker, Jennifer B. Lacy, Russell K. Gibbs
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Abstract
A method is provided to improve the quality of recycle of certain residues by modifying the separation of alkanes and alkane-like materials and carbonyl-containing impurities from the recycle during the manufacture of acetic acid by the carbonylation of methanol. The improvement comprises partitioning the residues by the addition of water obtained from aqueous streams containing up to 50 wt. % acetic acid and which have been treated in a catalytic distillation unit to react the acetic acid with methanol to form recyclable methyl acetate and water and wherein the water is separated from the organics by distillation.
Claims8
A process for the carbonylation of one or more compounds selected from the group consisting of methanol, dimethyl ether, or methyl acetate to acetic acid comprising;
- carbonylating said methanol, dimethyl ether or methyl acetate in a reaction medium further containing a Group VIII metal carbonylation catalyst, methyl iodide and water to form a reaction product comprising acetic acid and water, separating and purifying said reaction product to substantially dry acetic acid and one or more aqueous streams containing from about 5 to about 30 wt. % acetic acid, the improvement which comprises reacting at least a portion of at least one of the said aqueous streams from the drying column, or the splitter column with methanol in the presence of a second catalyst to form methyl acetate and water, separating the methyl acetate from the water and recycling the methyl acetate to the reactor.
Dependencies are inferred from the claim text.