Propane-1,3-diphosphonic acids for conditioning water
Abstract
Abstract Water is conditioned by adding thereto a corrosion-inhibiting, concretion inhibiting, precipitation retarding, deflocculating, dispersing or fluidifying amount of an acid of the formula ##STR1## in which R 1 and R 2 , independently of one another, represent hydrogen where a or b=1, or where a or b=0 represent an optionally substituted alkyl radical with 1-8 carbon atoms or an optionally substituted phenyl radical, R 3 represents hydrogen, an optionally substituted alkyl radical with 1 to 4 carbon atoms, an optionally substituted phenyl radical, a halogen atom from the group comprising fluorine, chlorine and bromine, a hydroxyl group, an alkoxy group containing 1 to 8 carbon atoms, a carboxyl group or a group --P(O)--(O) a --R 1 OH, R 4 represents hydrogen, an alkyl radical with 1 to 4 carbon atoms, an alkenyl radical with up to 3 carbon atoms, an optionally substituted phenyl radical, a carboxyl group, a fluorine or chlorine atom or a group --P(O)--(O) a --R 1 OH, or R 3 and R 4 together form a ring bridge with 3 to 5 methylene groups, R 5 represents hydrogen, an optionally substituted alkyl radical with 1 to 4 carbon atoms, a carboxymethyl or carboxyethyl group optionally substituted by a methyl group, a succinyl group or a group having the structure--CHR 4 --CHR 3 --P(O)--(O) a --R 1 OH or the structure--CH 2 --P(O)--(O) a --R 1 OH, R 6 represents an optionally substituted phenyl radical, a carboxyl group or a group having the structure --P(O)--(O) b --R 2 OH, and a and b independently of one another represent the numbers 0 or 1, or a salt thereof.
Inventors
- 👤 Hans-Dieter Block
- 👤 Herbert Kallfass
- 👤 Roland Kleinstuck
Bibliographic Details
Claims Analysis
Total Claims: 4References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |