EP0250189A1
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EP
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Process for carbonylating alcohol to carboxylic acid, especially methanol to acetic acid
Assignee: Celanese Corp
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Filing: 1987-06-15
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Granted: —
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Expires: 2007-06-15
Abstract
Abstract The carbonylation of an alcohol to produce a carboxylic acid, especially methanol to produce acetic acid, in a low water reaction medium containing a rhodium catalyst stabilized with an iodide salt, especially lithium iodide, along with alkyl iodide such as methyl iodide and alkyl acetate such as methyl acetate in specified proportions is improved by the addition of hydrogen in the feed gas to the low water reaction medium to obtain a reactor hydrogen partial pressure of at least about 4 psi. The presence of hydrogen in the reaction medium increases significantly the carbonylation reaction rate and reduced formation of byproduct carbon dioxide. The present reaction system not only provides an acid product of unusually low water content at unexpectedly favorable reaction rates but also, whether the water content is low or, as in the case of prior-art acetic acid technology, relatively high, is characterized by unexpectedly high catalyst stability; i.e., it is resistant to catalyst precipitation out of the reaction medium.
Inventors
- 👤 Paull G. Torrence
- 👤 Joel D. Hendricks
- 👤 Dennis D. Dickinson
- 👤 Adolfo Aguilo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 09:02
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/10; C07C51/12
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
131 words
In a process for producing a lower carboxylic acid by reacting a feed consisting essentially of an alcohol having one less carbon atom than said acid with carbon monoxide in a carbonylation reactor holding a liquid reaction medium containing a rhodium catalyst, the improvement which comprises: maintaining in said reaction medium during the course of said reaction at least a finite quantity of water together with effective amounts of (a) a catalyst stabilizer selected from the group consisting of iodide salts which are soluble in effective concentration in said reaction medium at reaction temperature, (b) the iodide derivative of a lower hydrocarbon corresponding to said alcohol, (c) the ester of said alcohol with said carboxylic acid, and (d) a partial pressure of hydrogen of at least 4 psi at reaction conditions.
Claim 2
Dependent Claim
131 words
In a process for producing a lower carboxylic acid by reacting a feed consisting essentially of an alcohol having one less carbon atom than said acid with carbon monoxide in a carbonylation reactor holding a liquid reaction medium containing a rhodium catalyst, the improvement which comprises: maintaining in said reaction medium during the course of said reaction at least a finite quantity of water together with effective amounts of (a) a catalyst stabilizer selected from the group consisting of iodide salts which are soluble in effective concentration in said reaction medium at reaction temperature, (b) the iodide derivative of a lower hydrocarbon corresponding to said alcohol, (c) the ester of said alcohol with said carboxylic acid, and (d) a partial pressure of hydrogen of at least 4 psi at reaction conditions.
Claim 3
Dependent Claim
27 words
The improvement of claim 1 wherein said iodide salt is an iodide salt of a metal selected from Groups Ia and IIa or a quaternary iodide salt.
Claim 4
Dependent Claim
13 words
The improvement of claim 2 wherein said iodide salt is lithium iodide salt.
Claim 5
Dependent Claim
20 words
The improvement of claim 1 wherein said hydrogen is maintained at a partial pressure of at least about 10 psi.
Claim 6
Dependent Claim
20 words
The improvement of claim 1 wherein said hydrogen is maintained at a partial pressure of at least about 20 psi.
Claim 7
Dependent Claim
20 words
The improvement of claim 1 wherein said hydrogen is maintained at a partial pressure of at least about 40 psi.
Claim 8
Dependent Claim
38 words
The improvement of claim 1 wherein hydrogen is co-fed with said carbon monoxide in an amount of at least about 0.3 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 9
Dependent Claim
41 words
The improvement of claim 1 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 0.3 mol % to about 10 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 10
Dependent Claim
41 words
The improvement of claim 1 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 1 mol % to about 5 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 11
Dependent Claim
19 words
The improvement of claim 1 wherein said water content is less than 14 wt.% of said liquid reaction medium.
Claim 12
Dependent Claim
23 words
The improvement of claim 1 wherein said water is present in amounts of between about 1 and 4 wt.% of said reaction medium.
Claim 13
Dependent Claim
113 words
In a process for producing acetic acid by reacting a feed consisting essentially of methanol with carbon monoxide in a carbonylation reactor holding a liquid reaction medium containing a rhodium catalyst, the improvement which comprises: maintaining catalyst stability and system productivity by maintaining in said reaction medium during the course of said reaction at least a finite concentration of water together with effective amounts of (a) a catalyst stabilizer selected from the group consisting of iodide salts which are soluble in said reaction medium in effective concentration at reaction temperature, (b) methyl iodide, and (c) methyl acetate, and (d) a partial pressure of hydrogen of at least about 4 psi at reaction conditions.
Claim 14
Dependent Claim
113 words
In a process for producing acetic acid by reacting a feed consisting essentially of methanol with carbon monoxide in a carbonylation reactor holding a liquid reaction medium containing a rhodium catalyst, the improvement which comprises: maintaining catalyst stability and system productivity by maintaining in said reaction medium during the course of said reaction at least a finite concentration of water together with effective amounts of (a) a catalyst stabilizer selected from the group consisting of iodide salts which are soluble in said reaction medium in effective concentration at reaction temperature, (b) methyl iodide, and (c) methyl acetate, and (d) a partial pressure of hydrogen of at least about 4 psi at reaction conditions.
Claim 15
Dependent Claim
38 words
The improvement of claim 12 wherein said iodide salt is a quaternary iodide salt or an iodide salt of a member of the group consisting of the metals of Group Ia and Group IIa of the periodic table.
Claim 16
Dependent Claim
14 words
The improvement of claim 13 wherein said iodide salt is an alkali metal iodide.
Claim 17
Dependent Claim
12 words
The improvement of claim 14 wherein the iodide salt is lithium iodide.
Claim 18
Dependent Claim
85 words
The improvement of claim 15 wherein the water content of said reaction medium is maintained at less than 14 wt.%, the lithium iodide content from about 2 wt.% to 20 wt.%, the methyl acetate content from about 0.5 wt.% to 30 wt.%, and the methyl iodide content from about 5 wt.% to 20 wt.% with the balance consisting essentially of acetic acid, and wherein rhodium catalyst is maintained in said reaction in a concentration of about 200 ppm to about 1000 ppm calculated as rhodium.
Claim 19
Dependent Claim
68 words
The improvement of claim 16 wherein, in weight percent, there is maintained in the reaction medium about 1 to 4 wt.% water, 10 to 20 wt.% lithium iodide, 12 to 16 wt.% methyl iodide, and 0.5 to 5 wt.% methyl acetate when optimal catalyst stabilization is desired or 2 to 5 wt.% methyl acetate when maximal reactor productivity is desired, with the balance consisting essentially of acetic acid.
Claim 20
Dependent Claim
20 words
The improvement of claim 12 wherein said hydrogen is maintained at a partial pressure of at least about 10 psi.
Claim 21
Dependent Claim
20 words
The improvement of claim 12 wherein said hydrogen is maintained at a partial pressure of at least about 20 psi.
Claim 22
Dependent Claim
20 words
The improvement of claim 12 wherein said hydrogen is maintained at a partial pressure of at least about 40 psi.
Claim 23
Dependent Claim
38 words
The improvement of claim 12 wherein hydrogen is co-fed with said carbon monoxide in an amount of at least about 0.3 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 24
Dependent Claim
41 words
The improvement of claim 12 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 0.3 mol % to about 10 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 25
Dependent Claim
41 words
The improvement of claim 16 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 1 mol % to about 5 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 26
Dependent Claim
19 words
The improvement of claim 22 wherein said water content is less than 14 wt.% of said liquid reaction medium.
Claim 27
Dependent Claim
20 words
The improvement of claim 17 wherein said hydrogen is maintained at a partial pressure of at least about 10 psi.
Claim 28
Dependent Claim
20 words
The improvement of claim 17 wherein said hydrogen is maintained at a partial pressure of at least about 20 psi.
Claim 29
Dependent Claim
20 words
The improvement of claim 17 wherein said hydrogen is maintained at a partial pressure of at least about 40 psi.
Claim 30
Dependent Claim
38 words
The improvement of claim 17 wherein hydrogen is co-fed with said carbon monoxide in an amount of at least about 0.3 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 31
Dependent Claim
41 words
The improvement of claim 17 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 0.3 mol % to about 10 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
Claim 32
Dependent Claim
41 words
The improvement of claim 17 wherein hydrogen is co-fed with said carbon monoxide in amounts of from about 1 mol % to about 5 mol % based on the carbon monoxide and hydrogen feed mixture to maintain said hydrogen partial pressure.
References Cited (Backward Citations)
US3717670A
Cited
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