Acetaldehyde removal from methyl acetate by distillation at elevated pressure
AssigneeCelanese International Corporation
InventorR. Jay WARNER
Life of this patent
Estimating the term…
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.
Claims25
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.
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 (R/F) 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;
- and
- (iii) withdrawing the residue stream depleted in acetaldehyde from the distillation column;
- (b) feeding the purified residue stream to a carbonylation reaction mixture along with carbon monoxide, the carbonylation mixture comprising water, a catalyst selected from rhodium catalysts, iridium catalysts and 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.