Process of bleaching

• US 20090205143A1
• Filed: 04/26/2006
• Published: 08/20/2009
• Est. Priority Date: 05/27/2005
• Status: Abandoned Application

• Current Assignee: Conopco, Inc. (Unilever PLC)
• Original Assignee: Conopco, Inc. (Unilever PLC)
• Inventors: Hage, Ronald, Warmoeskerken, Marinus Maria Cornelis Gerardus, Koek, Jean Hypolites
• Application Number:
  US11/920,787
• Publication Number:
  US 20090205143A1
• Time in Patent Office: Days
• US Class Current: 8/111
• CPC Class Codes: B01J 2231/70 Oxidation reactions, e.g. epoxidation, (di)hydroxylation, dehydrogenation and analogues
• CPC Class Codes: B01J 2531/72 Manganese
• CPC Class Codes: B01J 31/182 comprising aliphatic or saturated rings
• CPC Class Codes: B01J 31/22 Organic complexes
• CPC Class Codes: C11D 3/3932 Inorganic compounds or complexes
• CPC Class Codes: D06L 4/12 combined with specific additives
• CPC Class Codes: D21C 9/1036 Use of compounds accelerating or improving the efficiency of the processes
• CPC Class Codes: D21C 9/163 with peroxides

Abstract

The present invention concerns bleaching of substrates with an aqueous solution of a water soluble salt of a preformed transition metal catalyst together with hydrogen peroxide.

Claims

1. A method of catalytically treating a substrate, the substrate being a cellulose-containing substrate or starch containing substrate, with a preformed transition metal catalyst salt, the preformed transition metal catalyst salt having a non-coordinating counter ion, the method comprising the following steps:

(i) optionally dissolving a concentrate or solid form of a preformed transition metal catalyst salt in an aqueous medium to yield an aqueous solution of the preformed transition metal catalyst salt;

(ii) adding the aqueous solution of the preformed transition metal catalyst salt to a reaction vessel; and

,

(iii) adding hydrogen peroxide to the reaction vessel,

wherein the preformed transition metal catalyst salt is a mononuclear or dinuclear complex of a Mn(III) or Mn(IV) transition metal catalyst for catalytically treating the substrate with hydrogen peroxide, the non-coordinating counter ion of said transition metal selected to provide a preformed transition metal catalyst salt that has a water solubility of at least 30 g/l at 20°

C. and wherein the ligand of the transition metal catalyst is of formula (I);

wherein;

p is 3;

R is independently selected from;

hydrogen, C1-C6-alkyl, CH2CH2OH, and CH2COOH, or one of R is linked to the N of another Q via an ethylene bridge;

R1, R2, R3, and R4 are independently selected from;

H, C1-C4-alkyl, and C1-C4-alkylhydroxy, and the substrate is brought into contact with a mixture of the aqueous solution of the preformed transition metal catalyst salt and the hydrogen peroxide.

2. A method according to claim 1, wherein R is independently selected from:

CH₃, C₂H₅, CH₂CH₂OH and CH₂COOH.

3. A method according to claim 1, wherein R1, R2, R3, and R4 are independently selected from:

H and Me.

4. A method according to claim 1, wherein the catalyst is derived from a ligand selected from the group consisting 1,4,7-Trimethyl-1,4,7-triazacyclononane (Me₃-TACN) and 1,2,-bis-(4,7,-dimethyl-1,4,7,-triazacyclonon-1-yl)-ethane (Me₄-DTNE).

5. A method according to claim 1, wherein the preformed transition metal catalyst salt is a dinuclear Mn(III) or Mn(IV) complex with at least one O²⁻

bridge.

6. A method according to claim 1, wherein the preformed transition metal catalyst salt has a water solubility of at least 50 g/l at 20°

C.

7. A method according to claim 6, wherein the salt is that selected from the group consisting of chloride, acetate, sulphate, and nitrate.

8. A method according to claim 7, wherein the salt is acetate.

9. A method according to claim 1, wherein the aqueous solution of the preformed transition metal catalyst salt is in a buffer system that maintains the solution in the pH range 2 to 7.

10. A method according to claim 1, wherein the preformed transition metal catalyst salt is present at a concentration in the range from 0.1 to 10 wt % in the aqueous solution in step (ii).

11. A method according to claim 9, wherein the concentration is in the range from 0.5 to 8 wt %.

12. A method according to claim 1, wherein during treatment of the substrate the aqueous solution comprises at least 80 wt % water.

13. A method according to claim 12, the aqueous solution comprises at least 90 wt % water.

14. A method according to claim 13, wherein the aqueous solution comprises at least 95 wt % water.

15. A method according to claim 1, wherein the pH of the aqueous solution of the preformed transition metal catalyst salt aqueous solution in step (ii) in the range from 2 to 7.

16. A method according to claim 15, wherein the pH is in the range from 4 to 6.

17. A method according to claim 16, wherein the pH is in the range from 4.5 to 5.5.

18. A method according to claim 1, wherein the substrate is selected from the group consisting of woven or knitted cotton cloths, industrial laundering and wood pulp.

19. A method according to claim 1, wherein the substrate is wood pulp.

20. A method according to claim 1, wherein the preformed transition metal catalyst salt has been formed by a contact and oxidation step that is carried out at least 24 hours before use.

25. A cellulose-containing substrate or a starch containing substrate, wherein the cellulose-containing substrate or the starch containing substrate has been treated by the method defined in claim 1.

21. Use of a preformed transition metal catalyst salt in an aqueous medium to bleach a substrate, the substrate being a cellulose-containing substrate or starch containing substrate, with hydrogen peroxide, wherein the preformed transition metal catalyst salt is a dinuclear Mn(III) or Mn(IV) complex with at least two O²⁻

bridges for catalytically treating the substrate with hydrogen peroxide, said transition metal catalyst a salt, wherein the preformed transition metal catalyst salt has a water solubility of at least 30 g/l at 20°

C. and wherein the ligand of the transition metal catalyst is of formula (I);

wherein;

p is 3;

R is independently selected from;

hydrogen, C1-C6-alkyl, CH₂CH₂OH, and CH₂COOH, or one of R is linked to the N of another Q via an ethylene bridge;

R1, R2, R3, and R4 are independently selected from;

H, C1-C4-alkyl, and C1-C4-alkylhydroxy.

22. Use according to claim 21, wherein R is independently selected from:

CH₃, C₂H₅, CH₂CH₂OH and CH₂COOH.

23. Use according to claim 21, wherein R1, R2, R3, and R4 are independently selected from:

H and Me.

24. Use according to claim 23, wherein the catalyst is derived from a ligand selected from the group consisting 1,4,7-Trimethyl-1,4,7-triazacyclononane (Me3-TACN) and 1,2,-bis-(4,7,-dimethyl-1,4,7,-triazacyclonon-1-yl)-ethane (Me4-DTNE).