Patent JPS5843740A successfully refreshed from Google Patents.
US4181676A
Expired / Lapsed
US
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Process for the preparation of dialkyl carbonates
Assignee: Bayer AG
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Filing: 1978-08-31
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Granted: 1980-01-01
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Expires: 1998-08-31
Abstract
Abstract An improved process for the preparation of a dialkyl carbonate by contacting a glycol carbonate with alcohol at an elevated temperature in the presence of an alkali metal or alkali metal compound, the improvement residing in employing less than 0.01 percent by weight of alkali metal and/or alkali metal compound, based upon the weight the reaction mixture.
Inventors
- 👤 Hans-Josef Buysch
- 👤 Heinrich Krimm
- 👤 Hans Rudolph
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:36
CPC Classifications
C; C07; C07C; C07C29/00; C07C29/128; C07C68/00; C07C68/06; C07C68/065; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/52
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
90 words
In a process for the preparation of a dialkyl carbonate by contacting a glycol carbonate of a 1,2-diol having 2 to 4 carbon atoms with an alcohol selected from the group consisting of methanol, ethanol, propanol, isopropanol, n-butanol, iso-butanol, allyl alcohol, amyl alcohol, cyclohexanol, ethylcyclohexanol, benzyl alcohol and methylglycol at an elevated temperature in the presence of an alkali metal or alkali metal compound the improvement which comprises employing less than 0.01 percent by weight of alkali metal or alkali metal compound based upon the weight of the reaction mixture.
Claim 2
Dependent Claim
90 words
In a process for the preparation of a dialkyl carbonate by contacting a glycol carbonate of a 1,2-diol having 2 to 4 carbon atoms with an alcohol selected from the group consisting of methanol, ethanol, propanol, isopropanol, n-butanol, iso-butanol, allyl alcohol, amyl alcohol, cyclohexanol, ethylcyclohexanol, benzyl alcohol and methylglycol at an elevated temperature in the presence of an alkali metal or alkali metal compound the improvement which comprises employing less than 0.01 percent by weight of alkali metal or alkali metal compound based upon the weight of the reaction mixture.
Claim 3
Dependent Claim
24 words
A process according to claim 1 wherein the alkali metal or alkali metal compound is present in an amount of 0.0005 to 0.009 percent.
Claim 4
Dependent Claim
23 words
A process according to claim 1 wherein the reaction is carried out at a temperature in the range of 50° to 250° C.
Claim 5
Dependent Claim
23 words
A process according to claim 1 wherein the reaction is carried out at a temperature in the range of 100° to 220° C.
Claim 6
Dependent Claim
19 words
A process according to claim 1 wherein the reaction is carried out in a closed vessel at autogenous pressure.
Claim 7
Dependent Claim
15 words
A process according to claim 3 wherein the process is carried out at normal pressure.
Claim 8
Dependent Claim
21 words
A process according to claim 3 wherein the process is carried out at a pressure of between 2 and 100 bars.
Claim 9
Dependent Claim
24 words
A process according to claim 1 wherein said alkali metal or alkali metal compound is a metal of lithium, sodium, potassium, rubidium or caesium.
Claim 10
Dependent Claim
34 words
A process according to claim 1 wherein an alkali metal compound is employed and the alkali metal compound is a hydride, oxide, hydroxide, alcoholate, amide or an alkali metal salt of an organic acid.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-12-31 | 1983-07-02 | 1984-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-12-31 | 1987-07-02 | 1988-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-12-31 | 1991-07-02 | 1992-01-01 | $7700.00 | Window Closed / Lapsed |