US3897429A
Expired / Lapsed
US
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Thiol methylation with methyl bromide
Assignee: EIDP Inc
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Filing: 1974-05-29
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Granted: 1975-07-29
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Expires: 1994-05-29
Abstract
Abstract Compound A is methylated to produce Compound B in the presence of a base in aqueous medium using methyl bromide as the alkylating agent. A preferred embodiment of the process invention adds as a process step the regeneration of the methyl bromide. The alkali metal bromide salt, MBr, formed in this reaction is reacted with methanol and sulfuric acid to regenerate methyl bromide. A
Inventors
- 👤 Frank R Haglid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 00:28
CPC Classifications
C; C07; C07D; C07D253/00; C07D253/02; C07D253/06; C07D253/065; C07D253/07; C07D253/075
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
7 words
IN THE PROCESS OF SYNTHESIZING THE COMPOUND
Claim 2
Dependent Claim
7 words
IN THE PROCESS OF SYNTHESIZING THE COMPOUND
Claim 3
Dependent Claim
7 words
In the process of synthesizing the compound
Claim 4
Dependent Claim
7 words
In the process of synthesizing the compound
Claim 5
Dependent Claim
14 words
in the presence of a base selected from hydroxides of sodium and potassium; and
Claim 6
Dependent Claim
14 words
in the presence of a base selected from hydroxides of sodium and potassium; and
Claim 7
Dependent Claim
7 words
in the presence of sodium hydroxide; and
Claim 8
Dependent Claim
7 words
in the presence of sodium hydroxide; and
Claim 9
Dependent Claim
59 words
at pH in the range of about 11.7 to 12.3, temperature in the range of about +5*C. to +15*C. and at atmospheric pressure; and wherein, for the regeneration, a. the filtrate water content is reduced to 40-45% by weight, b. the methanol charge is in a 15-25% excess, and c. the sulfuric acid charge is in a 15-25% excess.
Claim 10
Dependent Claim
59 words
at pH in the range of about 11.7 to 12.3, temperature in the range of about +5*C. to +15*C. and at atmospheric pressure; and wherein, for the regeneration, a. the filtrate water content is reduced to 40-45% by weight, b. the methanol charge is in a 15-25% excess, and c. the sulfuric acid charge is in a 15-25% excess.
Claim 11
Dependent Claim
14 words
in the presence of a base selected from hydroxides of sodium and potassium; and
Claim 12
Dependent Claim
14 words
in the presence of a base selected from hydroxides of sodium and potassium; and
Claim 13
Dependent Claim
23 words
at pH in the range of about 11.7 to 12.3, temperature in the range of about +5*C. to +15*C. and at atmospheric pressure.
Claim 14
Dependent Claim
23 words
at pH in the range of about 11.7 to 12.3, temperature in the range of about +5*C. to +15*C. and at atmospheric pressure.
Claim 15
Dependent Claim
128 words
at pH in the range 10-14, temperature in the range -15*C. to +30*C. and at atmospheric or autogenous pressure and wherein the step of regenerating the methyl bromide from the methylation step liquors comprises a. neutralizing the liquors to a pH in the range of 6.7 to 7.3 by addition of an acid selected from sulfuric and phosphoric; b. filtering to remove the unreacted Compound A; c. concentrating the filtrate by removal of water by distillation at atmospheric or reduced pressure to a water content of 40-50% by weight; d. charging the concentrate with methanol in a 10-30% excess; e. charging the concentrate with sulfuric acid in a 10-30% excess; and f. commencing distillation of methyl bromide when approximately 75% of the sulfuric acid amount has been charged.
Claim 16
Dependent Claim
128 words
at pH in the range 10-14, temperature in the range -15*C. to +30*C. and at atmospheric or autogenous pressure and wherein the step of regenerating the methyl bromide from the methylation step liquors comprises a. neutralizing the liquors to a pH in the range of 6.7 to 7.3 by addition of an acid selected from sulfuric and phosphoric; b. filtering to remove the unreacted Compound A; c. concentrating the filtrate by removal of water by distillation at atmospheric or reduced pressure to a water content of 40-50% by weight; d. charging the concentrate with methanol in a 10-30% excess; e. charging the concentrate with sulfuric acid in a 10-30% excess; and f. commencing distillation of methyl bromide when approximately 75% of the sulfuric acid amount has been charged.
Claim 17
Dependent Claim
19 words
at pH in the range 10-14, temperature in the range -15*C. to +30*C. and at atmospheric or autogenous pressure.
Claim 18
Dependent Claim
19 words
at pH in the range 10-14, temperature in the range -15*C. to +30*C. and at atmospheric or autogenous pressure.
Claim 19
Dependent Claim
28 words
Improved process of claim 2 wherein a. the mole ratio of methyl bromide to Compound A is in the range of 1-1.5 and b. the methylation is conducted
Claim 20
Dependent Claim
41 words
Improved process of claim 2 wherein a. the mole ratio of methyl bromide to Compound A is in the range of about 1.05 to 1.2 and the methyl bromide is added to the reaction mixture gradually; b. the methylation is conducted
Claim 21
Dependent Claim
29 words
Improved process of claim 1 wherein, for the methylation, a. the mole ratio of methyl bromide to A is in the range 1-1.5 and b. the methylation is conducted
Claim 22
Dependent Claim
45 words
Improved process of claim 5 wherein, for the methylation, a. the mole ratio of methyl bromide to Compound A is in the range of about 1.05 to 1.2 and the methyl bromide is added to the reaction mixture gradually and b. the methylation is conducted
References Cited (Backward Citations)
US3135737A
Cited
US3671523A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |