PROCESS FOR MAKING SOLID METHYLGLYCINE DIACETATE ALKALI METAL SALTS

Abstract

Process for making solid methylglycine diacetate (MGDA) alkali metal salt (A), said process comprising the steps of (a) providing a 40 to 60% by weight aqueous solution of said salt (A) having a temperature in the range of from 50 to 90° C., (b) crystallizing salt (A), (c) removing said crystalline salt (A) from the mother liquor by filtration, and (d) subjecting the water containing filter cake from step (c) to an extrusion step.

Claims

1. A process for making solid methylglycine diacetate (MGDA) alkali metal salt (A), said process comprising the steps of (a) providing a 40 to 60% by weight aqueous solution of said salt (A) having a temperature in the range of from 50 to 90° C., (b) crystallizing salt (A), (c) removing said crystalline salt (A) from the mother liquor by filtration, and (d) subjecting the water containing filter cake from step (c) to an extrusion step.

2. The process according to claim 1, wherein in step (d), the extrusion step is carried out in a piston press, a twin screw extruder or a single-screw extruder.

3. The process according to claim 1, wherein step (d) is followed by at least one step selected from (e) drying the extrudate, and (f) grinding the extrudate.

4. The process according to claim 1, wherein salt (A) is selected from compounds according to general formula (I)
[CH3-CH(COO)—N(CH2-COO)2]M3-xHx  (I) wherein M is selected from alkali metal cations, same or different, and x is in the range of from zero to 1.0.

5. The process according to claim 1, wherein salt (A) is selected from the racemic mixture and mixtures of the enantiomers with predominantly the L-enantiomer with an ee value in the range of from 0.1 to 30%.

6. The process according to claim 1, wherein the filter cake from step (c) has a water content in the range of from 1 to 40% by weight.

7. The process according to claim 1, wherein such solid salt (A) has a residual moisture content in the range of from 0.5 to 12% by weight.

8. The process according to claim 1, wherein the pressure at the exit of the respective piston press, twin screw extruder or single-screw extruder is in the range of from 0.1 to 200 bar.

9. The process according to claim 1, wherein step (c) includes a diaphragm squeeze subsequently to filtration.

10. The process according to claim 1, wherein 5 to 20% of the product from step (e) or (f) is returned to the filter cake and subjected to step (d).

11. The process according to claim 1, wherein the aqueous solution provided in step (a) further comprises a (co)polymer of (meth)acrylic acid (B).

12. Column-shaped particles of methylglycine diacetate (MGDA) alkali metal salt (A) with an average diameter in the range of from 0.1 to 20 mm and a length of at least 1 mm, said particles comprising (A1) in the range of from 1 to 10% by weight monoclinic alkali metal salt of MGDA, and (A2) in the range of from 90 to 99% by weight orthorhombic alkali metal salt of MGDA, percentages referring to the entire content of the crystalline salt (A), and wherein the crystalline content is 80 to 99% by weight referring to the entire content of the respective salt (A).

13. The column-shaped particles according to claim 12, wherein salt (A) is selected from compounds according to general formula (I)
[CH3-CH(COO)—N(CH2-COO)2]M3-xHx  (I) wherein M is selected from alkali metal cations, same or different, and x is in the range of from zero to 1.0.

14. The column-shaped particles according to claim 12, wherein salt (A) is the trisodium salt.

15. A method for making laundry detergents or cleaners comprising combining the column-shaped particles of claim 12 with at least one bleaching agent.

16. The column-shaped particles according to claim 13, wherein salt (A) is the trisodium salt.

17. The method according to claim 15, wherein the at least one bleaching agent is at least one peroxy compound.

Description

III. EXAMPLE DETERGENT COMPOSITIONS

[0185] From inventive granules, example detergent compositions for automatic dishwashing detergents can be formulated by mixing the respective components according to Table 2.

TABLE-US-00002 TABLE 2 Example detergent compositions for automatic dishwashing All amounts in g/sample ADW.1 ADW.2 ADW.3 either of IP.1 or C-IP.2 30 22.5 15 Protease 2.5 2.5 2.5 Amylase 1 1 1 n-C.sub.18H.sub.37—O(CH.sub.2CH.sub.2O).sub.9H 5 5 5 Sodium percarbonate 10.5 10.5 10.5 TAED 4 4 4 Na.sub.2CO.sub.3 19.5 19.5 19.5 Sodium citrate dihydrate 15 22.5 30 HEDP 0.5 0.5 0.5 ethoxylated optionally: optionally: optionally: polyethylenimine, 20 0.1 0.1 0.1 EO/NH group, M.sub.n: 30,000 g/mol

[0186] The inventive detergent compositions furnish excellent automatic dishwashing results.