US3860641A
Expired / Lapsed
US
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Process for the production of thioglycolic acid, beta-mercaptopropionic acid or salts thereof
Assignee: Akzo NV
•
Filing: 1973-10-09
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Granted: 1975-01-14
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Expires: 1993-10-09
Abstract
Abstract A process for producing thioglycolic acid, Beta -mercaptopropionic acid or their alkali or alkaline earth metal salts by heating a hydrogen sulfide such as sodium or potassium hydrogen sulfide with a xanthogenic acid ester such as CH3CH2O-CS-S(CH2)nCOOH or its sodium or potassium salt where n is an integer of 1 or 2. The initial salt of the mercaptocarboxylic acid product is readily converted into the free acid while advantageously recycling the filtrate containing a salt of xanthogenic acid for reaction with a monohaloacetic acid or a Beta -monohalopropionic acid to reform the xanthogenic acid ester reactant. Both thioglycolic acid and Beta -mercaptopropionic acid or their salts are valuable products widely used in the chemical industries.
Inventors
- 👤 Hans Georg Zengel
- 👤 Manfred Bergfeld
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 22:53
CPC Classifications
C; C07; C07C; C07C323/00; C07C329/00; Y; Y02; Y02P; Y02P20/00; Y02P20/50; Y02P20/582
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
13 words
A process as claimed in claim 1 wherein R'' is methyl or ethyl.
Claim 2
Dependent Claim
47 words
A process as claimed in claim 1 wherein said lower alkanol used as the reaction medium has the formula R''-OH where R'' is alkyl of 1 to 5 carbon atoms and both R'' radicals of the alkanol and the xanthogenic acid ester are identical to each other.
Claim 3
Dependent Claim
21 words
A process as claimed in claim 3 wherein R'' of the alkanol and the xanthogenic acid ester is methyl or ethyl.
Claim 4
Dependent Claim
17 words
A process as claimed in claim 1 wherein M of said hydrogen sulfide is sodium or potassium.
Claim 5
Dependent Claim
19 words
A process as claimed in claim 1 wherein the ester reactant is ethyl xanthogenic acetic acid of the formula
Claim 6
Dependent Claim
19 words
A process as claimed in claim 1 wherein the ester reactant is ethyl xanthogenic propionic acid of the formula
Claim 7
Dependent Claim
32 words
A process as claimed in claim 1 wherein the reaction is carried out at about the boiling temperature of the reaction medium and for a period of approximately 0.5 to 5 hours.
Claim 8
Dependent Claim
81 words
A process as claimed in claim 1 wherein the alkali or alkaline earth metal salt of the thioglycolic acid or Beta -mercaptopropionic acid is filtered off as a reaction product, and the filtrate containing an alkali or alkaline earth metal salt of xanthogenic acid is recycled after reaction with a haloacid of the formula X-(CH2)n-COOH where X is chlorine or bromine and n is an integer of 1 or 2, thereby forming said xanthogenic acid ester for reuse in the process.
Claim 9
Dependent Claim
30 words
A process as claimed in claim 9 wherein the filtered off alkali or alkaline earth metal salt of thioglycolic acid or Beta -mercaptopropionic acid is converted into the free acid.
Claim 10
Dependent Claim
41 words
A process as claimed in claim 9 wherein the metal M is sodium or potassium, the alkyl group R'' is methyl or ethyl and the R'' radicals of both the alkanol and the xanthogenic acid ester are identical to each other.
Claim 11
Dependent Claim
19 words
A process as claimed in claim 11 wherein the ester reactant is ethyl xanthogenic acetic acid of the formula
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) | 1978-01-13 | 1978-07-15 | 1979-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-13 | 1982-07-15 | 1983-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-13 | 1986-07-15 | 1987-01-14 | $7700.00 | Window Closed / Lapsed |