Patent US3864323A successfully refreshed from Google Patents.
US3864323A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing polycoagulants
Assignee: Czech Academy of Sciences
•
Filing: 1971-06-29
•
Granted: 1975-02-04
•
Expires: 1991-06-29
Abstract
Abstract Method of manufacturing polycoagulants for water purification is provided comprising polymerizing acrylonitrile in a 50 to 65 percent nitric acid solution at a concentration of between 10 and 20 percent of acrylonitrile by weight. The viscous solution thus obtained is maintained at temperatures between 20* and 45*C until a sample of the polymer, precipitated in water, is soluble in an aqueous alkaline solution at increased temperature. Thereafter, the partly hydrolyzed polymer, containing still a substantial amount of nitrilic groups in addition to the amidic and carboxylic groups, is precipitated in water in diluted nitric acid or in a lower aliphatic alcohol. The isolated copolymer is dissolved in an aqueous alkaline solution.
Inventors
- 👤 Artur Stoy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:56
CPC Classifications
C; C02; C02F; C02F1/00; C02F1/52; C02F1/54; C08; C08F; C08F8/00; C08F8/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
110 words
A METHOD OF MANUFACTURING A POLYCOAGULANT COMPRISING POLYMERIZING 10 TO 20 PERCENT BY WEIGHT OF ACRYLONITRILE IN A NITRIC ACID SOLUTION OF ABOUT 50 TO 65 PERCENT CONCENTRATION, SAID POLYMERIZATION BEING CARRIED OUT AT A TEMPERATURE BETWEEN 10* AND 20*C IN THE PRESENCE OF AN INORGANIC FREE RADICAL CATALYST, AND THEREAFTER SUBJECTING THE RESULTANT POLYMER SOLUTION TO AN INCREASED TEMPERATURE FOR A PERIOD OF TIME RANGING BETWEEN ABOUT 4 - 10 HOURS AT 41* - 50*C AND 5 - 12 DAYS AT 22* - 25*C SUFFICIENT TO EFFECT PARTIAL ACID HYDROLYSIS OF SAID POLYMER UNTIL SAID POLYMER FORMS A POLYCOAGULANT COMPLETELY SOLUBLE IN AN AQUEOUS SOLUTION OF A WEAK ALKALI.
Claim 2
Independent Claim
110 words
A METHOD OF MANUFACTURING A POLYCOAGULANT COMPRISING POLYMERIZING 10 TO 20 PERCENT BY WEIGHT OF ACRYLONITRILE IN A NITRIC ACID SOLUTION OF ABOUT 50 TO 65 PERCENT CONCENTRATION, SAID POLYMERIZATION BEING CARRIED OUT AT A TEMPERATURE BETWEEN 10* AND 20*C IN THE PRESENCE OF AN INORGANIC FREE RADICAL CATALYST, AND THEREAFTER SUBJECTING THE RESULTANT POLYMER SOLUTION TO AN INCREASED TEMPERATURE FOR A PERIOD OF TIME RANGING BETWEEN ABOUT 4 - 10 HOURS AT 41* - 50*C AND 5 - 12 DAYS AT 22* - 25*C SUFFICIENT TO EFFECT PARTIAL ACID HYDROLYSIS OF SAID POLYMER UNTIL SAID POLYMER FORMS A POLYCOAGULANT COMPLETELY SOLUBLE IN AN AQUEOUS SOLUTION OF A WEAK ALKALI.
Claim 3
Dependent Claim
48 words
The method as set forth in claim 1, wherein the nitric acid solution initially contains 15 to 20 percent of said acrylonitrile by weight together with a small amount of a chain transfer agent sufficient to avoid cross-linking but insufficient to avoid macromolecular branching of the resultant polymer.
Claim 4
Dependent Claim
24 words
The method as set forth in claim 2, wherein less than 1 percent by weight of urea is used as said chain transfer agent.
Claim 5
Dependent Claim
39 words
The method as set forth in claim 1, wherein the nitric acid solution initially contains 15 to 20 percent of said acrylonitrile by weight together with a small amount of an organic polymerization initiator capable of causing chain transfer.
Claim 6
Dependent Claim
34 words
The method as set forth in claim 1, wherein said partially hydrolyzed polycoagulant is precipitated from said nitric acid solution only after an aliquot portion thereof is soluble in a hot aqueous alkaline solution.
Claim 7
Dependent Claim
35 words
The method as set forth in claim 5, wherein said partially hydrolyzed polycoagulant is precipitated by pouring said nitric acid solution into water, dilute nitric acid or an aqueous solution of a lower aliphatic alcohol.
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) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |