US4663477A
Expired / Lapsed
US
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Process for the hydrolysis of dialkyl carbonates
Assignee: Union Carbide Corp
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Filing: 1986-03-27
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Granted: 1987-05-05
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Expires: 2006-03-27
Abstract
Abstract A process is provided for the utilization of dialkyl carbonates formed as by-products in a continuous process for the synthesis of oxalic acid esters from nitrous acid esters and carbon monoxide and wherein the esters are subsequently used as intermediates in the production of commercially useful products, such as ethylene glycol. The process comprises contacting a mixture containing the by-product comprised of a dialkyl carbonate with an aqueous solution of a metal carbonate under hydrolyzing conditions whereby the dialkyl carbonate is converted to the corresponding alkanol and the metal carbonate is converted to metal bicarbonate. Upon distillation of the alkanol from the mixture the bicarbonate is converted back to the metal carbonate which can then be recycled from the bottoms to the hydrolyzing zone for use in further hydrolysis of by-product. The alkanol is recycled for use in the continuous process.
Inventors
- 👤 John W. Crandall
- 👤 James E. Deitzler
- 👤 Louis A. Kapicak
- 👤 Fedor Poppelsdorf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:43
CPC Classifications
C; C07; C07C; C07C69/00; C07C69/34; C07C69/36; C07C29/00; C07C29/09; C07C29/095; C07C31/00; C07C31/02; C07C31/04; C07C67/00; C07C67/36
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
181 words
In a continuous process for the synthesis of oxalic acid diesters by the reaction of an ester of nitrous acid and carbon monoxide to form an intermediate mixture containing an oxalic acid diester and undesirable reaction by-products, and wherein said oxalic acid diester is subsequently processed into commercially useful products, the improvement which comprises converting and recycling said by-products comprised of a dialkyl carbonate having from 1 to 4 carbon atoms in each alkyl group, by the steps of: (1) contacting a mixture containing said by-products comprised of said dialkyl carbonate with an aqueous solution of a metal carbonate, selected from the group consisting of potassium, sodium, cesium and lithium carbonate, in a hydrolyzing zone and under hydrolyzing conditions whereby said dialkyl carbonate is converted to the corresponding alkanol and said metal carbonate is converted to said metal bicarbonate, (2) distilling said mixture to convert said metal bicarbonate to said metal carbonate, (3) removing as distillate said alkanol and carbon dioxide, and recycling said alkanol for use in said continuous process, and (4) recycling said metal carbonate to said hydrolyzing zone.
Claim 2
Dependent Claim
181 words
In a continuous process for the synthesis of oxalic acid diesters by the reaction of an ester of nitrous acid and carbon monoxide to form an intermediate mixture containing an oxalic acid diester and undesirable reaction by-products, and wherein said oxalic acid diester is subsequently processed into commercially useful products, the improvement which comprises converting and recycling said by-products comprised of a dialkyl carbonate having from 1 to 4 carbon atoms in each alkyl group, by the steps of: (1) contacting a mixture containing said by-products comprised of said dialkyl carbonate with an aqueous solution of a metal carbonate, selected from the group consisting of potassium, sodium, cesium and lithium carbonate, in a hydrolyzing zone and under hydrolyzing conditions whereby said dialkyl carbonate is converted to the corresponding alkanol and said metal carbonate is converted to said metal bicarbonate, (2) distilling said mixture to convert said metal bicarbonate to said metal carbonate, (3) removing as distillate said alkanol and carbon dioxide, and recycling said alkanol for use in said continuous process, and (4) recycling said metal carbonate to said hydrolyzing zone.
Claim 3
Dependent Claim
14 words
The process of claim 1 wherein said ester of nitrous acid is methyl nitrite.
Claim 4
Dependent Claim
11 words
The process of claim 1 wherein said by-product is methyl carbonate.
Claim 5
Dependent Claim
17 words
The process of claim 1 wherein said by-product is a mixture of methyl carbonate and methyl formate.
Claim 6
Dependent Claim
11 words
The process of claim 1 wherein said by-product is ethyl carbonate.
Claim 7
Dependent Claim
11 words
The process of claim 1 wherein said by-product is propyl carbonate.
Claim 8
Dependent Claim
11 words
The process of claim 1 wherein said byproduct is butyl carbonate.
Claim 9
Dependent Claim
12 words
The process of claim 1 wherein said metal carbonate is potassium carbonate.
Claim 10
Dependent Claim
12 words
The process of claim 1 wherein said metal carbonate is sodium carbonate.
Claim 11
Dependent Claim
12 words
The process of claim 1 wherein said metal carbonate is cesium carbonate.
Claim 12
Dependent Claim
12 words
The process of claim 1 wherein said metal carbonate is lithium carbonate.
Claim 13
Dependent Claim
21 words
The process of claim 1 wherein said aqueous solution of metal carbonate contains about 20 percent by weight of potassium carbonate.
Claim 14
Dependent Claim
30 words
The process of claim 12 wherein said potassium carbonate is employed in a molar excess of that required to convert all of the dialkyl carbonate present to the corresponding alkanol.
Claim 15
Dependent Claim
13 words
The process of claim 1 wherein said hydrolyzing zone is a tubular reactor.
Claim 16
Dependent Claim
152 words
In a continuous process for the synthesis of oxalic acid diesters by the reaction of an ester of nitrous acid and carbon monoxide to form an intermediate mixture containing an oxalic acid diester and undesirable reaction by-products, and wherein said oxalic acid diester is subsequently processed into commercially useful products, the improvement which comprises converting and recycling said by-products comprised of at least methyl carbonate by the steps of: (1) contacting a mixture containing said by-products compriscd of methyl carbonate with an aqucous solution of potassium carbonate, in a hydrolyzing zone and under hydrolyzing conditions whereby said methyl carbonate is converted to methanol and said potassium carbonate is converted to potassium bicarbonate, (2) distilling said mixture to convert said potassium bicarbonate to potassium carbonate, (3) removing as distillate methanol and carbon dioxide, and recycling said methanol for use in said continuous process, and (4) recycling said potassium carbonate to said hydrolyzing zone.
Claim 17
Dependent Claim
152 words
In a continuous process for the synthesis of oxalic acid diesters by the reaction of an ester of nitrous acid and carbon monoxide to form an intermediate mixture containing an oxalic acid diester and undesirable reaction by-products, and wherein said oxalic acid diester is subsequently processed into commercially useful products, the improvement which comprises converting and recycling said by-products comprised of at least methyl carbonate by the steps of: (1) contacting a mixture containing said by-products compriscd of methyl carbonate with an aqucous solution of potassium carbonate, in a hydrolyzing zone and under hydrolyzing conditions whereby said methyl carbonate is converted to methanol and said potassium carbonate is converted to potassium bicarbonate, (2) distilling said mixture to convert said potassium bicarbonate to potassium carbonate, (3) removing as distillate methanol and carbon dioxide, and recycling said methanol for use in said continuous process, and (4) recycling said potassium carbonate to said hydrolyzing zone.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1990-05-04 | 1990-11-03 | 1991-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-05-04 | 1994-11-03 | 1995-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-05-04 | 1998-11-03 | 1999-05-05 | $7700.00 | Window Closed / Lapsed |