US4587306A
Expired / Lapsed
US
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Preparation of polymers of hydroxamic functions
Assignee: Societe National Elf Aquitaine
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Filing: 1983-08-24
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Granted: 1986-05-06
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Expires: 2003-08-24
Abstract
Abstract Improvements in the preparation of polymers of hydroxamic functions that consist in heating a polyacrylamide aqueous solution with a hydroxylamine salt at temperatures of from about 50° to 85° C. The polymers obtained are used as adjuvants of soil drilling muds, especially in petroleum drilling. The invention concerns itself with improvements in the preparation of polymers of hydroxamic functions, the resulting novel polymers, and applications thereof. The invention provides for the obtention of such polymers having a desired number of hydroxamic groups without noticeable formation of objectionable secondary products; it makes possible, in addition, the preparation of derivatives wherein the chain of the polymer and/or the hydroxamic groups contain different substituents.
Inventors
- 👤 Lino Vio
- 👤 Gilles Meunier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:12
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/34
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
73 words
A process for the preparation of a polymer with hydroxamic functions by heating an aqueous solution of polyacrylamide with hydroxylamine salt, which comprises carrying out the reaction at a temperature of from about 50° to 85° C., and wherein the replacement rate of the amido groups by the hydroxamic groups is controlled by using a proportion of hydroxylamine salt of about 0.2 to 1.2 mol per amide group present in the polyacrylamide used.
Claim 2
Dependent Claim
73 words
A process for the preparation of a polymer with hydroxamic functions by heating an aqueous solution of polyacrylamide with hydroxylamine salt, which comprises carrying out the reaction at a temperature of from about 50° to 85° C., and wherein the replacement rate of the amido groups by the hydroxamic groups is controlled by using a proportion of hydroxylamine salt of about 0.2 to 1.2 mol per amide group present in the polyacrylamide used.
Claim 3
Dependent Claim
21 words
A process according to claim 1 wherein the reaction is carried out at a temperature between about 60° and 80° C.
Claim 4
Dependent Claim
107 words
A process for the preparation of a polymer with hydroxamic functions by heating an aqueous solution of polyacrylamide with hydroxylamine salt, which comprises carrying out the reaction at a temperature of from about 50° to 85° C., wherein the replacement rate of the amido groups by the hydroxamic groups is controlled by using a proportion of hydroxylamine salt of about 0.2 to 1.2 mol per amide group present in the polyacrylamide used, and wherein the remaining ammonia and hydroxylamine are eliminated from the reaction medium, after the heating, by a second heating of from about 85° to 100° C. for a period not exceeding about 2 hours.
Claim 5
Dependent Claim
107 words
A process for the preparation of a polymer with hydroxamic functions by heating an aqueous solution of polyacrylamide with hydroxylamine salt, which comprises carrying out the reaction at a temperature of from about 50° to 85° C., wherein the replacement rate of the amido groups by the hydroxamic groups is controlled by using a proportion of hydroxylamine salt of about 0.2 to 1.2 mol per amide group present in the polyacrylamide used, and wherein the remaining ammonia and hydroxylamine are eliminated from the reaction medium, after the heating, by a second heating of from about 85° to 100° C. for a period not exceeding about 2 hours.
Claim 6
Dependent Claim
17 words
A process according to claim 3, wherein the second heating is between about 15 and 75 minutes.
Claim 7
Dependent Claim
27 words
A process according to claim 3, wherein said proportion is between about 0.35 and 0.65 mols of hydroxylamine salt for each amide group of the polyacrylamide used.
Claim 8
Dependent Claim
19 words
A process according to claim 3, wherein the pH of the aqueous solution is between about 6.2 and 6.8.
Claim 9
Dependent Claim
56 words
A process according to claim 1, wherein a part of the acrylamide moieties in the polyacrylamide is replaced by moieties originating from monomers copolymerizable with the acrylamide, the monomers being selected from the group consisting of acrylic or methacrylic acid, an ester or salt thereof, maleic anhydride, vinyl ester, vinyl pyrrolidone, butadiene, styrene, acrylonitrile and alkanolacrylamide.
Claim 10
Dependent Claim
34 words
A process according to claim 1, wherein a part of the acrylamide moieties of the polymer used is replaced by moieties of a member selected from the group consisting of thioacrylates, thiomethacrylates and thioacrylamide.
Claim 11
Dependent Claim
31 words
A process according to claim 1, wherein the molecular weight of the polymer subjected to the action of the hydroxylamine salt has a molecular weight of from about 1,000 to 20,000.
Claim 12
Dependent Claim
16 words
A process according to claim 9, wherein the molecular weight is between about 1,200 and 6,000.
Claim 13
Dependent Claim
37 words
A process according to claim 1, wherein the hydroxylamine salt is a hydrochloride or sulphate of an R--NH--OR' substituted hydroxylamine wherein R and R' are organic substituents and either R or R' may be a hydrogen atom.
Claim 14
Dependent Claim
14 words
A process according to claim 1, wherein the hydroxylamine salt is that of thiohydroxylamine.
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) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |