Patent US4039395A successfully refreshed from Google Patents.
US4039395A
Expired / Lapsed
US
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Purification of acetic acid
Assignee: Monsanto Co
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Filing: 1975-08-11
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Granted: 1977-08-02
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Expires: 1995-08-11
Abstract
Abstract A process is provided for purification and drying of acetic acid containing water and methyl iodide and hydrogen iodide as contaminants. The process comprises distillation in a two-zone system wherein the major part of the methyl iodide and hydrogen iodide and some water are removed as overhead and bottoms, respectively, from the first zone; a stream from the middle section of the first zone is introduced into a second zone into which there is also introduced a stream of methanol; and a stream of dry purified acid is recovered from the bottom of said second zone. The process provides both for the recovery of the iodine components and the methanol added for re-use in production of additional acetic acid by the reaction of methanol and/or methyl acetate with carbon monoxide in contact with a catalyst system formed on mixing of a rhodium or iridium component and an iodine component in the presence of carbon monoxide.
Inventors
- 👤 Roy T. Eby
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:31
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/43; C07C51/44; C07C51/487; Y; Y10; Y10S; Y10S203/00; Y10S203/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
217 words
A process for the removal and recovery of iodine-containing components and the drying of acetic acid which consists of a. introducing a stream of acetic acid containing water, methyl iodide and hydrogen iodide into a first distillation zone intermediate the ends thereof, b. removing as an overhead fraction from said first distillation zone the major proportion of the methyl iodide and a portion of the water, c. removing from the bottom of said first distillation zone the major proportion of the hydrogen iodide, d. withdrawing a stream from the middle section of said first distillation zone and introducing at least a portion of said stream into the upper section of a second distillation zone, e. introducing a stream of methanol into the lower section of said second distillation zone, f. removing overhead from said second distillation zone a stream containing the remainder of the water and methyl iodide present together with any methyl acetate generated by the addition of excess methanol into said zone, condensing said stream, returning a portion thereof as reflux to said second distillation zone and removing the remaining portion thereof from said second distillation zone, and g. removing at or near the bottom of said second distillation zone a product acetic acid essentially dry and substantially free of hydrogen iodide and methyl iodide.
Claim 2
Dependent Claim
217 words
A process for the removal and recovery of iodine-containing components and the drying of acetic acid which consists of a. introducing a stream of acetic acid containing water, methyl iodide and hydrogen iodide into a first distillation zone intermediate the ends thereof, b. removing as an overhead fraction from said first distillation zone the major proportion of the methyl iodide and a portion of the water, c. removing from the bottom of said first distillation zone the major proportion of the hydrogen iodide, d. withdrawing a stream from the middle section of said first distillation zone and introducing at least a portion of said stream into the upper section of a second distillation zone, e. introducing a stream of methanol into the lower section of said second distillation zone, f. removing overhead from said second distillation zone a stream containing the remainder of the water and methyl iodide present together with any methyl acetate generated by the addition of excess methanol into said zone, condensing said stream, returning a portion thereof as reflux to said second distillation zone and removing the remaining portion thereof from said second distillation zone, and g. removing at or near the bottom of said second distillation zone a product acetic acid essentially dry and substantially free of hydrogen iodide and methyl iodide.
Claim 3
Dependent Claim
22 words
The process of claim 1 wherein the stream of step (a) is introduced into the lower third of said first distillation zone.
Claim 4
Dependent Claim
22 words
The process of claim 2 wherein the stream of step (d) is introduced into the upper one-third of said second distillation zone.
Claim 5
Dependent Claim
22 words
The process of claim 3 wherein the stream of step (e) is introduced into the lower one-fourth of said second distillation zone.
Claim 6
Dependent Claim
33 words
The process of claim 4 wherein the amount of methanol introduced is from one part by weight to 20 parts by weight per part by weight of hydrogen iodide contained in said zone.
Claim 7
Dependent Claim
32 words
The process of claim 5 wherein the weight ratio of methanol introduced into said second distillation zone to the hydrogen iodide contained in said zone is from about 2:1 to about 7:1.
Claim 8
Dependent Claim
43 words
The process of claim 5 wherein the overhead fraction of step (b) is condensed and separated into a light phase and a heavy phase, a portion of said light phase being returned as reflux to the upper part of said first distillation zone.
Claim 9
Dependent Claim
59 words
The process of claim 7 wherein a portion of the withdrawn stream of step (d) is recycled to said first distillation zone below the point at which said stream of step (d) is withdrawn from said first distillation zone and wherein the recycle step takes place upstream of the introduction of said withdrawn stream into said second distillation zone.
Claim 10
Dependent Claim
21 words
The process of claim 8 wherein the stream of step (g) is removed from the bottom of said second distillation zone.
Claim 11
Dependent Claim
31 words
The process of claim 8 wherein the stream of step (g) is removed in vapor form from a point above the liquid level in the bottom of said second distillation zone.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-08-01 | 1981-01-31 | 1981-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-08-01 | 1985-01-31 | 1985-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-08-01 | 1989-01-31 | 1989-08-02 | $7700.00 | Window Closed / Lapsed |