US4493771A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scale inhibiting with compounds containing quaternary ammonium and methylenephosphonic acid groups
Assignee: Dow Chemical Co
•
Filing: 1984-03-06
•
Granted: 1985-01-15
•
Expires: 2004-03-06
Abstract
Abstract Compounds having improved properties of inhibiting the precipitation of metal ions when used in threshold amounts have been made which are derivatives of ammonia or di- or polyamines in which the amine hydrogens have been substituted with both methylenephosphonic acid groups or their salts and hydroxypropyl quaternaryammonium halide groups. Thus, ammonia can have two hydrogens replaced with methylenephosphonic groups while the third is replaced with a hydroxypropyltrimethylammonium chloride group; and three hydrogens of ethylenediamine can be replaced with methylenephosphonic groups, the fourth being replaced with a hydroxypropyltrimethylammonium chloride group.
Inventors
- 👤 David A. Wilson
- 👤 Wilfred W. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:23
CPC Classifications
C; C07; C07F; C07F9/00; C07F9/02; C07F9/28; C07F9/38; C07F9/3804; C07F9/3808; C07F9/3817; C02; C02F; C02F5/00; C02F5/08; C02F5/10; C02F5/14
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
A process for inhibiting scale formation in an aqueous solution containing alkaline earth metal ions which comprises adding to said aqueous solution a threshold amount of a compound having the formula ##STR3## wherein the A, B, C and D substituents are independently selected from the group consisting of hydrogen, methylenephosphonic acid or salt thereof and 2-hydroxy-3 (trialkylammonium halide) propyl wherein each alkyl has from 1 to 5 carbon atoms, n is 0 to 15, and wherein said substituents include at least one methylenephosphonic acid group, or salt thereof, and at least one 2-hydroxy-3 (trialkylammonium halide) propyl group.
Claim 2
Dependent Claim
97 words
A process for inhibiting scale formation in an aqueous solution containing alkaline earth metal ions which comprises adding to said aqueous solution a threshold amount of a compound having the formula ##STR3## wherein the A, B, C and D substituents are independently selected from the group consisting of hydrogen, methylenephosphonic acid or salt thereof and 2-hydroxy-3 (trialkylammonium halide) propyl wherein each alkyl has from 1 to 5 carbon atoms, n is 0 to 15, and wherein said substituents include at least one methylenephosphonic acid group, or salt thereof, and at least one 2-hydroxy-3 (trialkylammonium halide) propyl group.
Claim 3
Dependent Claim
39 words
The process of claim 1 wherein the compound employed has the formula wherein n is 1 and one of A, B, C or D is a 2-hydroxy-3 (trialkylammonium halide) propyl group and the remaining substituents are methylenephosphonic acid groups.
Claim 4
Dependent Claim
21 words
The process of claim 2 wherein the methylenephosphonic acid groups are present in the form of a salt of the acid.
Claim 5
Dependent Claim
12 words
The process of claim 3 wherein the salt is a sodium salt.
Claim 6
Dependent Claim
41 words
The process of claim 1 wherein the compound employed has the formula wherein n is 0 and one of A, B, or D is a 2-hydroxy-3 (trialkylammonium halide) propyl and the remaining two substituents are methylenephosphonic acid groups or salts thereof.
Claim 7
Dependent Claim
21 words
The process of claim 5 wherein the methylenephosphonic acid groups are present in the form of a salt of the acid.
Claim 8
Dependent Claim
12 words
The process of claim 6 wherein the salt is a sodium salt.
References Cited (Backward Citations)
US2847442A
Cited
US3336221A
Cited
US3434969A
Cited
US3859211A
Cited
US3867286A
Cited
US4075243A
Cited
US4234511A
Cited
US4330487A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-01-15 | 1988-07-16 | 1989-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-15 | 1992-07-16 | 1993-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-15 | 1996-07-16 | 1997-01-15 | $7700.00 | Window Closed / Lapsed |