Compositions – Frost-preventing – ice-thawing – thermostatic – thermophoric,...
Patent
1998-02-10
1999-08-24
Green, Anthony J.
Compositions
Frost-preventing, ice-thawing, thermostatic, thermophoric,...
106 13, 252 71, 252 73, 252 77, 252 79, C09K 318, C09K 500
Patent
active
059421509
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the use of polymers having repeating succinyl units as antifreezing agents and to corresponding antifreezing compositions.
Antifreezing compositions have long been known and act by their lowering of freezing point which is observed in water. Glycol is widely used. However, it is required of substances which are present in metal-clad radiators or other industrial installations which are to be protected against the freezing of water that they have anticorrosive properties and, since they are often released into the environment, that they are biodegradable (Rompp, Thieme, 1993, p. 1502).
The preparation and use of polyaspartic acid (PAA) and its derivatives has long been the subject of numerous publications and patents.
The preparation can be carried out by thermal polycondensation of aspartic acid in accordance with J. Org. Chem. 26, 1084 (1961). An intermediate which appears initially is polysuccinimide (PSI), which is referred to therein as "anhydropolyaspartic acid". PSI can be converted into PAA by hydrolysis.
U.S. Pat. No. 4 839 461 (=EP-A 0 256 366) describes the preparation of polyaspartic acid from maleic anhydride, water and ammonia.
DE-A 2 253 190 describes a process for preparing polyamino acid derivatives, especially polyaspartic acid derivatives. According to that document not only aspartic acid but also maleic acid derivatives (monoammonium salt and monoamide) are thermally polymerized to the intermediate PSI, which can subsequently be reacted, in appropriate solvents, with amines to form the desired polyamino acid derivatives.
U.S. Pat. No. 5,296,578 describes the preparation of PSI from maleic anhydride, water and ammonia. In this case the mass is reacted in a number of hours by way of highly viscous phase states to form the solid PSI, and is subsequently hydrolyzed to PAA.
U.S. Pat. No. 5,288,783 describes the preparation of PAA from maleic acid or fumaric acid, water and ammonia. Maleic anhydride is mixed with water in a stirred vessel and is converted to maleic acid with cooling. By adding concentrated ammonia solution, the maleic acid monoammonium salt is prepared. The water present is subsequently evaporated and the dry monoammonium salt is polymerized at temperatures from 190 to 350.degree. C. Alternatively, it is proposed to process further the monoammonium salt, which is present in aqueous solution, by extrusion at temperatures from 160 to 200.degree. C. to form PSI. The PSI prepared by one of the two procedures is then hydrolyzed under alkaline conditions to form PAA.
EP-A 593 187 describes the preparation of PSI by thermal polymerization of maleamic acid at temperatures from 160 to 330.degree. C. in a reaction period of from 2 minutes to 6 hours. Reference is also made to polycondensation in the solvent using condensation auxiliaries.
DE-A 4 221 875 describes the preparation of modified polyaspartic acids by polycondensation and their use as additives for detergents, cleaning products, water treatment compositions and antideposition agents in the evaporative concentration of sugars.
DE-A 4 300 020 relates to a process for preparing polymers of aspartic acid by reacting maleic anhydride and ammonia or amines and to the use of the polymers as scale inhibitors, as dispersants and as an additive to detergents and cleaning products.
DE-A 4 307 114 relates to a process for preparing reaction products of polyaspartimides and amino acids and for using the reaction products as an additive to detergents and cleaning products, as a scale inhibitor and as a dispersant.
DE-A 4 310 995 relates to the use of polyaspartic acids in cleaning formulations, DE-A 4 311 237 to their use in chain lubricants.
The object of the present invention is to provide improved antifreezing compositions.
The present invention relates to the use of polymers having repeating succinyl units, especially of polyaspartic acids, as antifreezing agent.
The polymers used in accordance with the invention have repeating succinyl units with one of the following structures: ##STR1## preferably ##STR2##
In
REFERENCES:
patent: 4839461 (1989-06-01), Boehmke
patent: 4971724 (1990-11-01), Kalota et al.
patent: 5288783 (1994-02-01), Wood
patent: 5296578 (1994-03-01), Koskan et al.
patent: 5393868 (1995-02-01), Freeman et al.
patent: 5548036 (1996-08-01), Kroner et al.
patent: 5639832 (1997-06-01), Kroner et al.
J. Org. Chem. 26, (1961)--pp. 1084-1091, Kovacs et al, "Chemical Studies of Polyaspartic acids". No month.
Romp, Thieme, 1993, pp. 1502-1503 No month.
Groth Torsten
Heuer Lutz
Joentgen Winfried
Moritz Ralf-Johann
Bayer Aktiengesellschaft
Green Anthony J.
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