# US 10,370,620 B2 · Method for producing polyaspartic acid under reflux cooling

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- Number: US 10,370,620 B2
- Document ID: US10370620B2
- Status: Granted
- Kind: B2
- Application number: 15/757,469
- Filed: 2016-09-05
- Published: 2018-09-06
- Granted: 2019-08-06
- Earliest claimed: 2015-09-08
- Assignees: BASF SE
- Applicants: BASF SE
- Inventors: Gazi Tuerkoglu; Juergen Detering; Dietrich Fehringer; Christian Benz
- Web page: https://patentgrep.com/patent/US10370620B2

## CPC

- C11D 3/3719: {Polyamides or polyimides}
- C08G 69/04: Preparatory processes
- C08G 69/10: Alpha-amino-carboxylic acids {(polysuccinimides C08G73/1092)}
- C08G 73/1092: {Polysuccinimides}
- C11D: DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

Provided herein is a method for producing polyaspartic acid under reflux cooling. Further provided herein are compositions including polyaspartic acid obtainable through the method. Also provided herein is a use of polyaspartic acids obtainable through the method in dishwashing agents, detergents, and cleaning agents.

## Claims

### Claim 1

A method for producing polyaspartic acid, the method comprising:
(a) contacting a mixture of:
(i) aspartic acid, and
(ii) 1 to 25 mol % of an acidic catalyst;
in a reactor;
(b) heating the mixture according to (a) under reflux cooling without distillative removal of water at a reaction temperature of 100 to 220° C. up to a degree of conversion of the aspartic acid of at least 1%;
(c) polycondensing the reaction mixture according to (b) with simultaneous distillative removal of water at 170 to 250° C. to produce polycondensates; and
(d) hydrolyzing the polycondensates according to (c) with addition of a base.

### Claim 2 (depends on 1)

The method according to claim 1, wherein contacting the mixture according to (a) comprises adding 3 to 15 mol % of the acidic catalyst.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the acidic catalyst is methanesulfonic acid.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the polycondensing (c) is carried out at 200 to 250° C.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the base is selected from the group consisting of aqueous sodium hydroxide solution, aqueous potassium hydroxide solution, calcium hydroxide, barium hydroxide, sodium carbonate, potassium carbonate, ammonia, and ammonium hydroxide.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the degree of conversion of the aspartic acid during the heating (b) is at least 5%.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the temperature of the heating (b) is 160 to 180° C.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the contacting (a) further comprises adding water to the mixture.

### Claim 9 (depends on 1)

The method according to claim 1 further comprising:
(e) acidifying salts of polyaspartic acid obtained by the hydrolyzing (d).

### Claim 10 (depends on 9)

The method according to claim 9, wherein the acidifying (e) is carried out with a mineral acid or an acidic ion exchanger.