Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1997-03-27
1998-01-20
Shippen, Michael L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
528328, C07D22900
Patent
active
057103275
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for preparing modified polyaspartic acids by condensing aspartic acid with cocondensable compounds without diluent at temperatures of at least 140.degree. C. and, where appropriate, hydrolyzing the condensates with alkali metal and/or alkaline earth metal bases in aqueous medium.
2. Discussion of the Background
WO-A-94/011486 discloses modified polyaspartic acids obtainable by polycondensation of 1-99.9 mol% aspartic acid with 99-0.1 mol% cocondensable compounds. Examples of suitable cocondensable compounds are fatty acids, polybasic carboxylic acids, anhydrides of polybasic carboxylic acids, alcohols, amines, alkoxylated alcohols and alkoxylated amines. The condensation is preferably carried out in the presence of phosphoric acid as catalyst. Salts of aspartic acid and salts of polybasic carboxylic acids or fatty acids can, according to the statements in this reference, be cocondensed only if inorganic acids are additionally used in the cocondensation. The acids have to be removed from the condensates after the polycondensation.
SUMMARY OF THE INVENTION PREFERRED EMBODIMENTS
It is an object of the present invention to provide a process for preparing modified polyaspartic acids in which the condensation takes place in the absence of inorganic acids.
We have found that this object is achieved by a process for preparing modified polyaspartic acids by condensing aspartic acid with cocondensable compounds without diluent at temperatures of at least 140.degree. C. and, where appropriate, hydrolyzing the condensates with alkali metal and/or alkaline earth metal bases in aqueous medium, employing as cocondensable compounds and
L-, DL- or D-aspartic acid can be employed as aspartic acid. The aspartic acid may contain water. The particle size of the aspartic acid crystals has no effect on the polycondensation.
Suitable group (a) cocondensable compounds are polybasic carboxylic acids or anhydrides of polybasic carboxylic acids.
Examples of polybasic carboxylic acids are oxalic acid, adipic acid, fumaric acid, maleic acid, itaconic acid, aconitic acid, succinic acid, malonic acid, suberic acid, azelaic acid, pyridinedicarboxylic acid, furandicarboxylic acid, phthalic acid, terephthalic acid, diglycolic acid, glutaric acid, substituted C.sub.4 -dicarboxylic acids, for example mercaptosuccinic acid, sulfosuccinic acid, C.sub.1 -C.sub.26 -alkylsuccinic acids (eg. octylsuccinic acid or dodecylsuccinic acid), C.sub.2 -C.sub.26 -alkenylsuccinic acids (eg. octenylsuccinic acid or dodecenylsuccinic acid), 1,2,3-propanetricarboxylic acid, 1,1,3,3-propanetetracarboxylic acid, 1,1,2,2-ethanetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,2,3-propanetetracarboxylic acid, 1,3,3,5-pentanetetracarboxylic acid, 1,2,4-benzenetricarboxylic acid and 1,2,4,5-benzenetetracarboxylic acid.
Where the abovementioned polybasic carboxylic acids are able to form anhydrides, these can also be employed as component (a) in the preparation of the polycocondensates, eg. succinic anhydride, the dianhydride of butanetetracarboxylic acid, phthalic anhydride, acetylcitric anhydride, maleic anhydride, itaconic anhydride and aconitic anhydride.
The compounds of component (a) which are preferably used are citric acid, maleic anhydride and maleic acid. Citric acid is very particularly preferably employed. 0.01-2, preferably 0.1-1.1, mol of polybasic carboxylic acids or their anhydrides are used per mole of aspartic acid.
Ammonia is employed as component (b). Ammonia can be used in gaseous form or in the form of an aqueous solution. 0.01-2, preferably 0.1-1.1, mol of ammonia are employed for 1 mol of aspartic acid.
The reaction components can be mixed before the condensation or else under the condensation conditions. In order to achieve maximally homogeneous mixing of the reactants before the start of the condensation, it is possible, for example, to dissolve aspartic acid and polybasic carboxylic acids in water and add the required amount of ammonia in
REFERENCES:
patent: 5408028 (1995-04-01), Wood
patent: 5478919 (1995-12-01), Koshan
patent: 5548036 (1996-08-01), Kroner
patent: 5574113 (1996-11-01), Kroner
patent: 5639723 (1997-06-01), Kroner
Kroner Matthias
Schornick Gunnar
BASF - Aktiengesellschaft
Shippen Michael L.
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