US4734527A
Expired / Lapsed
US
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Process for preparing 2,6-di-tertiarybutyl-4-mercaptophenol
Assignee: Aventis Inc
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Filing: 1986-10-17
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Granted: 1988-03-29
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Expires: 2006-10-17
Abstract
Abstract In a process for making 2,6-di-tertiarybutyl-4-mercaptophenol by the Zn/acid reduction of bis (3,5-di-tertiarybutyl-4-hydroxyphenyl)polysulfide the addition of catalytic amounts of lead to the zinc reagent results in substantial improvement in the process.
Inventors
- 👤 Richard C. Krauss
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:15
CPC Classifications
C; C07; C07C; C07C323/00
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
44 words
In a process for making 2,6-ditertiarybutyl-4-mercaptophenol by reduction of a bis(3,5-ditertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zinc catalyst and acid, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 2
Dependent Claim
44 words
In a process for making 2,6-ditertiarybutyl-4-mercaptophenol by reduction of a bis(3,5-ditertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zinc catalyst and acid, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 3
Dependent Claim
27 words
Process of claim 1 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of zinc.
Claim 4
Dependent Claim
27 words
Process of claim 1 wherein the reaction mixture contains from about 2700 to about 3300 parats by weight of lead per million parts by weight of zinc.
Claim 5
Dependent Claim
49 words
In a process of making 2,6-ditertiarybutyl-4-mercaptophenol by sulfurization of 2,6-ditertiarybutylphenol and reduction of the sulfurization product in the presence of a zinc catalyst and acid, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 6
Dependent Claim
49 words
In a process of making 2,6-ditertiarybutyl-4-mercaptophenol by sulfurization of 2,6-ditertiarybutylphenol and reduction of the sulfurization product in the presence of a zinc catalyst and acid, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 7
Dependent Claim
27 words
Process of claim 4 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of zinc.
Claim 8
Dependent Claim
27 words
Process of claim 4 wherein the reaction mixture contains from about 2700 to about 3300 parts by weight of lead per million parts by weight of zinc.
Claim 9
Dependent Claim
54 words
In a process for making 4,4'-isopropylidene-dithio-bis-(2,6-di-tertiarybutylphenol) by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zine catalyst and acid, and reacting the reduction product with acetone under acidic conditions, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 10
Dependent Claim
54 words
In a process for making 4,4'-isopropylidene-dithio-bis-(2,6-di-tertiarybutylphenol) by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zine catalyst and acid, and reacting the reduction product with acetone under acidic conditions, the improvement which comprises contacting the zinc with an amount of lead which is catalytic for said reduction prior to carrying out the reduction.
Claim 11
Dependent Claim
28 words
Process of claim 7 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of total zinc.
Claim 12
Dependent Claim
27 words
Process of claim 7 wherein the reaction mixture contains from about 2700 to about 3300 parts by weight of lead per million parts by weight of zinc.
Claim 13
Dependent Claim
41 words
In a process for making 2,6-di-tertiarybutyl-4-mercaptophenol by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zinc catalyst and acid, the improvement which comprises conducting the reduction in the presence of an amount of lead which is catalytic for said reduction.
Claim 14
Dependent Claim
41 words
In a process for making 2,6-di-tertiarybutyl-4-mercaptophenol by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenyl)polysulfide in the presence of a zinc catalyst and acid, the improvement which comprises conducting the reduction in the presence of an amount of lead which is catalytic for said reduction.
Claim 15
Dependent Claim
27 words
Process of claim 10 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of zinc.
Claim 16
Dependent Claim
27 words
Process of claim 10 wherein the reaction mixture contains from about 2700 to about 3300 parts by weight of lead per million parts by weight of zinc.
Claim 17
Dependent Claim
46 words
In a process for making 2,6-di-tertiarybutyl-4-mercaptophenol by sulfurization of 2,6-di-tertiarybutylphenol and reduction of the sulfurization product in the presence of a zinc catalyst and acid, the improvement which comprises conducting said reduction in the presence of an amount of lead which is catalystic for said reduction.
Claim 18
Dependent Claim
46 words
In a process for making 2,6-di-tertiarybutyl-4-mercaptophenol by sulfurization of 2,6-di-tertiarybutylphenol and reduction of the sulfurization product in the presence of a zinc catalyst and acid, the improvement which comprises conducting said reduction in the presence of an amount of lead which is catalystic for said reduction.
Claim 19
Dependent Claim
31 words
Process of the reduction step of claim 13 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of zinc.
Claim 20
Dependent Claim
31 words
Process of the reduction step of claim 13 wherein the reaction mixture contains from about 2700 to about 3300 parts by weight of lead per million parts by weight of zinc.
Claim 21
Dependent Claim
51 words
In a process for making 4,4'-isopropylidenedithio-bis-(2,6-di-tertiarybutylphenol) by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenol)polysulfide in the presence of a zinc catalyst and acid, and reacting the reduction product with acetone under acidic conditions, the improvement which comprises conducting said reduction in the presence of an amount of lead which is catalytic for said reduction.
Claim 22
Dependent Claim
51 words
In a process for making 4,4'-isopropylidenedithio-bis-(2,6-di-tertiarybutylphenol) by reduction of a bis(3,5-di-tertiarybutyl-4-hydroxyphenol)polysulfide in the presence of a zinc catalyst and acid, and reacting the reduction product with acetone under acidic conditions, the improvement which comprises conducting said reduction in the presence of an amount of lead which is catalytic for said reduction.
Claim 23
Dependent Claim
27 words
Process of claim 16 wherein the reaction mixture contains from about 1200 to about 5000 parts by weight of lead per million parts by weight of zinc.
Claim 24
Dependent Claim
27 words
Process of claim 16 wherein the reaction mixture contains from about 2700 to about 3300 parts by weight of lead per million parts by weight of zinc.
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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) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |