Acetaldehyde removal from methyl acetate by distillation at elevated pressure
AssigneeCelanese International Corporation
InventorR. Jay Warner
Life of this patent
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Abstract
A method for removing acetaldehyde from a mixture of methyl acetate, methanol and acetaldehyde includes: (a) feeding the mixture of methyl acetate, methanol and acetaldehyde to a distillation column; (b) distilling the feed mixture of methyl acetate methanol and acetaldehyde at a pressure of 10 psig or more to generate an overhead vapor stream enriched in acetaldehyde as compared with the feed mixture and a residue stream depleted in acetaldehyde as compared with the feed mixture; and (c) withdrawing the residue stream depleted in acetaldehyde from the distillation column.
Claims22
A method for removing acetaldehyde from a mixture of methyl acetate, methanol and acetaldehyde comprising:
- (a) feeding the mixture of methyl acetate, methanol and acetaldehyde to a distillation column;
- (b) distilling the feed mixture of methyl acetate methanol and acetaldehyde at a pressure of 10 psig or more to generate an overhead vapor stream enriched in acetaldehyde as compared with the feed mixture and a residue stream depleted in acetaldehyde as compared with the feed mixture;
- and
- (c) withdrawing the residue stream depleted in acetaldehyde from the distillation column, wherein at least a portion of the overhead stream is refluxed to the distillation column wherein the distillation column is operated at a reflux to feed (R/F) ratio of greater than 2.
The method according to 1, wherein the distillation column is operated at a reflux to feed (R/F) ratio of greater than 3.
A method for removing acetaldehyde from a mixture of methyl acetate, methanol and acetaldehyde comprising:
- (a) feeding a mixture of methyl acetate, methanol and acetaldehyde to a distillation column, wherein the feed mixture comprises at least about 5 wt. % methanol, more than 100 ppm acetaldehyde and the balance methyl acetate;
- (b) distilling the feed mixture of methyl acetate, methanol and acetaldehyde at a pressure of 10 psig or more to generate an overhead vapor stream enriched in acetaldehyde as compared with the feed mixture and a residue stream depleted in acetaldehyde as compared with the feed mixture;
- (c) refluxing a portion of the overhead stream to the distillation column;
- (d) controlling the temperature of the overhead vapor stream, the pressure of the distillation column and the reflux to feed (RIF) ratio of the distillation column such that the residue stream has an acetaldehyde content of less than 100 ppm;
- and
- (e) withdrawing the residue stream from the distillation column.
A process for the production of acetic acid comprising:
- (a) purifying a mixture of methyl acetate, methanol and acetaldehyde to remove acetaldehyde by way of:
- (i) feeding the mixture of methyl acetate, methanol and acetaldehyde to a distillation column;
- (ii) distilling the feed mixture-of methyl acetate methanol and acetaldehyde at a pressure of 10 psig or more to generate an overhead vapor stream enriched in acetaldehyde as compared with the feed mixture and a residue stream depleted in acetaldehyde as compared with the feed mixture, wherein at least a portion of the overhead stream is refluxed to the distillation column, and wherein the distillation column is operated at a reflux to feed (R/F) ratio of greater than 2;
- and
- (iii) withdrawing the residue stream depleted in acetaldehyde from the distillation column;
- (b) feeding the residue stream to a carbonylation reaction mixture along with carbon monoxide, the carbonylation mixture comprising water, a catalyst selected from rhodium catalysts, iridium catalysts or mixtures thereof, a methyl iodide promoter and acetic acid;
- and
- (c) recovering acetic acid from the carbonylation mixture.
Dependencies are inferred from the claim text.