Chemical composition and method
The invention relates to a novel composition useful as a feed at production of chlorine dioxide, said composition being an aqueous solution comprising from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and at least one of a protective colloid, a radical scavenger or a phosphonic acid based complexing agent, wherein the pH of the aqueous solution is from about 1 to about 4. The invention also concerns a process for producing chlorine dioxide using the novel composition.
1. Composition useful as a feed at production of chlorine dioxide, said composition being an aqueous solution comprising from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and at least one of a protective colloid, a radical scavenger or a phosphonic acid based complexing agent, wherein the pH of the aqueous solution is from about 1 to about 4.
2. Composition as claimed in claim 1 , wherein the aqueous solution comprises at least one phosphonic acid based complexing agent.
3. Composition as claimed in claim 1 , wherein the aqueous solution comprises at least one protective colloid.
4. Composition as claimed in claim 1 , wherein the aqueous solution comprises at least one radical scavenger.
5. Composition as claimed in claim 2 , wherein the aqueous solution comprises from about 0.1 to about 5 mmoles/liter of at least one phosphonic acid based complexing agent.
6. Composition as claimed claim 2 , wherein the at least one phosphonic acid based complexing agent is selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, 1-aminoethane-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylene diamine tetra (methylenephosphonic acid), hexamethylene diamine tetra (methylenephosphonic acid), diethylenetriamine penta (methylenephosphonic acid), diethylenetriamine hexa (methylenephosphonic acid), morpholinomethane diphosphonic acid, N,N-dimethyl aminodimethyl diphosphonic acid, aminomethyl diphosphonic acid, and salts thereof.
7. Composition as claimed claim 5 , wherein the at least one phosphonic acid based complexing agent is selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, 1-aminoethane-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylene diamine tetra (methylenephosphonic acid), hexamethylene diamine tetra (methylenephosphonic acid), diethylenetriamine penta (methylenephosphonic acid), diethylenetriamine hexa (methylenephosphonic add), morpholinomethane diphosphonic acid, N,N-dimethyl aminodimethyl diphosphonic acid, aminomethyl diphosphonic acid, and salts thereof.
8. Composition as claimed in claim 1 , wherein the water content is from about 20 to about 70 wt %.
9. Composition as claimed in claim 8 , wherein the water content is from about 30 to about 60 wt %.
10. Composition as claimed in claim 1 , wherein the aqueous solution comprises from about 1 to about 10 mmoles/liter of alkali metal nitrate.
11. Composition as claimed claim 1 , wherein the content of chloride ions in the aqueous solution is less than 0.5 mmoles/liter.
12. Composition as claimed claim 1 , wherein the molar ratio of H 2 O 2 to ClO 3 in the aqueous solution is from about 0.2:1 to about 2:1.
13. Composition as claimed claim 1 , wherein the aqueous solution comprises from about 3 to about 6 moles/liter of alkali metal chlorate, from about 3 to about 5 moles/liter of hydrogen peroxide and from about 0.5 to about 3 mmoles/liter of at least one phosphonic acid based complexing agent.
14. Composition as claimed claim 1 , wherein the pH of the aqueous solution is from about 1.5 to about 3.5.
15. Composition as claimed in claim 3 , wherein the at least one protective colloid is a tin compound.
16. Composition as claimed in claim 15 , wherein the tin compound is alkali metal stannate.
17. Composition as claimed in claim 4 , wherein the at least one radical scavenger is a pyridine carboxylic acid.
18. Composition as claimed in claim 17 , wherein the pyridine carboxylic acid is 2,6-pyridine carboxylic acid.
19. Composition as claimed in claim 5 , wherein the aqueous solution comprises from about 0.5 to about 3 mmoles/liter of at least one phosphonic acid based complexing agent.
20. Composition as claimed in claim 3 comprising from about 0.001 to about 0.5 moles/liter of at least one protective colloid.
21. Composition as claimed in claim 4 comprising from about 0.01 to about 1 mole/liter of at least one radical scavenger.
22. Composition as claimed in claim 6 , wherein the at least one phosphonic acid based complexing agent comprises diethylene triamine penta(methylene phosphonic acid) or a salt thereof.
23. Composition as claimed in claim 6 , wherein the at least one phosphonic acid based complexing agent comprises aminotri(methylenephosphonic acid) or a salt thereof.
24. Composition as claimed in claim 6 , wherein the at least one phosphonic acid based complexing agent comprises 1-hydroxyethylidene-1,1-diphosphonic acid or a salt thereof.
25. Composition as claimed in claim 1 , wherein the composition is storage stable for at least fourteen days.
26. Composition useful as a feed for production of chlorine dioxide, said composition being an aqueous solution comprising from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and at least one of from about 0.001 to about 0.5 moles/liter alkali metal stannate, from about 0.01 to about 1 mole/liter of a pyridine carboxylic acid or from about 0.1 to about 5 mmoles/liter of a phosphonic acid based complexing agent, wherein the pH of the aqueous solution is from about 1 to about 4 and the molar ratio of H 2 O 2 to ClO 3 − is from about 0.2:1 to about 2:1.
27. Composition useful as a feed for production of chlorine dioxide, said composition being an aqueous solution comprising from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and from about 0.1 to about 5 mmoles/liter of at least one phosphonic acid based complexing agent, wherein the pH of the aqueous solution is from about 1 to about 3.5 and the molar ratio of H 2 O 2 to ClO 3 − is from about 0.2:1 to about 2:1.
28. A storage vessel containing a composition useful as a feed for production of chlorine dioxide, said composition being an aqueous solution comprising from about 1 to about 6.5 moles/liter of alkali metal chlorate, from about 1 to about 7 moles/liter of hydrogen peroxide and from about 0.1 to about 5 mmoles/liter of at least one phosphonic acid based complexing agent, wherein the pH of the aqueous solution is from about 1 to about 3.5 and the molar ratio of H 2 O 2 to ClO 3 − is from about 0.2:1 to about 2:1, and wherein said composition has a rate of H 2 O 2 decomposition, measured from the time of forming said composition, of no more than 5% in fourteen days.
29. Composition as claimed in claim 1 , wherein the content of alkali metal chloride in the composition is less than 0.5 wt % calculated as NaCl in NaClO 3 .
30. Composition as claimed in claim 26 , wherein the content of alkali metal chloride in the composition is less than 0.5 wt % calculated as NaCl in NaClO 3 .
31. Composition as claimed in claim 27 , wherein the content of alkali metal chloride in the composition is less than 0.5 wt % calculated as NaCl in NaClO 3 .
32. Composition as claimed in claim 9 , wherein the water content is from about 40 to about 55 wt %.