US4966982A
Expired / Lapsed
US
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Process for the production of lactide
Assignee: Mitsui Toatsu Chemicals Inc
•
Filing: 1989-04-26
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Granted: 1990-10-30
•
Expires: 2009-04-26
Abstract
Abstract Disclosed is a process for the production of highly pure lactide, especially having a sufficiently high purity to be usable as a raw material for the synthesis of polymers, by heating a 2-halopropionate in a non-aqueous solvent.
Inventors
- 👤 Hiroshi Ono
- 👤 Heng Phala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 20:10
CPC Classifications
C; C07; C07D; C07D319/00; C07D319/10; C07D319/12
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
89 words
A process for the formation of a lactide, comprising the step of heating an alkali metal or alkaline earth metal salt of a 2-halopropionic acid in a non-aqueous solvent which has a low boiling point, which has a high solubility for the lactide and which has a low solubility for alkali metal or alkaline earth metal halides, at a reaction temperature of 100° to 250° C. and in the vicinity of a pressure produced by the solvent itself at the reaction temperature to convert the salt into the lactide
Claim 2
Dependent Claim
89 words
A process for the formation of a lactide, comprising the step of heating an alkali metal or alkaline earth metal salt of a 2-halopropionic acid in a non-aqueous solvent which has a low boiling point, which has a high solubility for the lactide and which has a low solubility for alkali metal or alkaline earth metal halides, at a reaction temperature of 100° to 250° C. and in the vicinity of a pressure produced by the solvent itself at the reaction temperature to convert the salt into the lactide
Claim 3
Dependent Claim
24 words
The process as claimed in claim 1 wherein the non-aqueous solvent is one member selected from the group consisting of Ketones, esters and ethers.
Claim 4
Dependent Claim
34 words
The process as claimed in claim 1 wherein the non-aqueous solvent is one member selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, isopropyl acetate, diethyl ether, dioxane and tetrahydrofuran.
Claim 5
Dependent Claim
28 words
The process as claimed in claim 1 wherein the non-aqueous solvent is a Ketone selected from the group consisting of acetone, methyl ethyl ketone and methyl isobutyl ketone.
Claim 6
Dependent Claim
14 words
The process as claimed in claim 1 wherein the 2-halopropionic acid is 2-chloropropionic acid.
Claim 7
Dependent Claim
24 words
The process as claimed in claim 1 wherein the alkali metal salt of the 2-halopropionic acid is the sodium salt of the 2-halopropionic acid.
Claim 8
Dependent Claim
24 words
The process as claimed in claim 1 wherein the alkali metal salt of the 2-halopropionic acid is the potassium salt of the 2-halopropionic acid.
Claim 9
Dependent Claim
25 words
The process as claimed in claim 1 wherein the alkaline earth metal salt of the 2-halopropionic acid is the calcium salt of the 2-halopropionic acid.
Claim 10
Dependent Claim
25 words
The process as claimed in claim 1 wherein the alkaline earth metal salt of the 2-halopropionic acid is the barium salt of the 2-halopropionic acid.
Claim 11
Dependent Claim
17 words
The process as claimed in claim 1 wherein the lactide is separated from the reaction product mixture.
Claim 12
Dependent Claim
37 words
The process as claimed in claim 10 wherein the lactide is separated by removing a solid phase from the reaction product mixture to obtain a liquid phase and then evaporating the non-aqueous solvent from the liquid phase.
Claim 13
Dependent Claim
65 words
A process for producing a lactide, comprising the step of heating an alkali metal or alkaline earth metal salt of a 2-halopropionic acid in a non-aqueous solvent selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone and dioxane at a reaction temperature of 140° to 200° C., in the vicinity of an autogenous pressure of the solvent at the reaction temperature.
Claim 14
Dependent Claim
65 words
A process for producing a lactide, comprising the step of heating an alkali metal or alkaline earth metal salt of a 2-halopropionic acid in a non-aqueous solvent selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone and dioxane at a reaction temperature of 140° to 200° C., in the vicinity of an autogenous pressure of the solvent at the reaction temperature.
Claim 15
Dependent Claim
15 words
The process as claimed in claim 12 wherein the autogenous pressure is about 25 atmospheres.
References Cited (Backward Citations)
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US3960152A
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US4033938A
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US4835293A
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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) | 1993-10-29 | 1994-04-30 | 1994-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-29 | 1998-04-30 | 1998-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-29 | 2002-04-30 | 2002-10-30 | $7700.00 | Window Closed / Lapsed |