Frémy's salt

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Frémy's salt
Potassium-nitrosodisulfonate-2D.png
Potassium-nitrosodisulfonate-unit-cell-3D-balls.png
Identifiers
CAS number 14293-70-0
PubChem 3032624
Properties
Molecular formula K2NO(SO3)2
Molar mass 268.33 g/mol (potassium salt)
Hazards
R-phrases R14 R20/21/22
S-phrases S36
Main hazards Harmful (Xn)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Frémy's salt, discovered in 1845 by Edmond Frémy (1814–1894), is a chemical compound and a strong oxidizing agent. The formal name is disodium nitrosodisulfonate or Na2NO(SO3)2, but the expression "Frémy's salt" refers equally well to potassium nitrosodisulfonate, also known as potassium peroxylamine disulfonate. Frémy’s salt (chemical formula: (K4[ON(SO3)2]2) is commonly known as potassium nitrodisulfonate radical dianion (NDS) and potassium peroxylamine disulfonate (K2[NO(SO3)2]). NDS, a product of disassociation of Frémy’s salt, is commonly used to examine the mechanism of oxidation and hydroxylation.[1] Frémy’s salt is a commercially accessible dimer of NDS, it is also a relatively stable source of water-soluble nitroxyl radical that is used as an electronic spin resonance (ESR) standard for g-value determination and radical quantization it is also mainly used in oxidation reactions.[2][3] Great care must be taken to exclude oxygen from vials or glassware where Frémy's salt is stored, as a rapid and highly exothermic decomposition occurs spontaneously in air.

Applications[edit]

The nitroso compound is a persistent radical like TEMPO. It is especially useful in oxidations of anilines and phenols to quinones.[4][5]

Fremy's salt, being a long-lived free radical, is a useful reagent for electron paramagnetic resonance (EPR) work. The molecule gives an intense EPR spectrum dominated by three lines of equal intensity with a spacing of about 13 G (= 1.3 mT). For more details, see Wertz and Bolton (1972).[6]

Fremy’s salt is commonly used in oxidation of aromatic amine and phenol structures.[7][8] It can also be used as a model for peroxyl radicals in studies that examine the antioxidant mechanism of action in a wide range of natural products.[9][10] Also are used in the synthesis of metabolites which are found to later bind with DNA.[11] One of its few biological applications involves evaluation of radical scavenging activity and EPR kinetic studies.[12] It is also a useful tool in understanding the reduction mechanism by ascorbic acid (AscH2).[11]

Preparation[edit]

Fremy's salt is commercially available. It can be prepared by the addition of sodium nitrite, sodium bicarbonate, and sulfur dioxide to disodium hydroxylaminedisulfonate and carbon dioxide followed by one-electron oxidation by electrolysis in a basic solution.[13] This reaction must be carried at 5˚C or lower with constant stirring.[14]

Other Reactions:

HNO2 + 2 HSO3 → HON(SO3)22− + H2O
3 HON(SO3)22− + MnO4 + H+ → 3 ON(SO3)22− + MnO2(s) + 2 H2O
2 ON(SO3)22− + 4 K+ → K4[ON(SO3)2]2(s)

In the solid phase, potassium nitrodisulfonate has a bright yellowish-brown color, but it is bright violet in aqueous solutions.[14] EPR measurements can be made to ensure the purity and paramagnetism of the compound.

References[edit]

  1. ^ Zielonka, Jacek, et al. (2005). "Mechanistic similarities between oxidation of hydroethidine by Fremy’s salt and superoxide: Stopped-flow optical and EPR studies". Free Radical Biology & Medicine 39 (7): 853–863;. doi:10.1016/j.freeradbiomed.2005.05.001. PMID 16140206. 
  2. ^ Weil, J. A.; Bolton, J. R.; Wertz, J. E. (1994), "Electron paramagnetic resonance: elementary theory and practical applications", Org. Synth. 
  3. ^ Zielonka, Jacek, et al. (2005). "Mechanistic similarities between oxidation of hydroethidine by Fremy’s salt and superoxide: Stopped-flow optical and EPR studies". Free Radical Biology & Medicine 39 (7): 853–863;. doi:10.1016/j.freeradbiomed.2005.05.001. PMID 16140206. 
  4. ^ See, for example, Islam, Imadul Islam; Skibo, Edward B.; Dorr, Robert T.; Alberts, David S. (1991). "Structure-activity studies of antitumor agents based on pyrrolo[1,2-a]benzimidazoles: new reductive alkylating DNA cleaving agents". Journal of Medicinal Chemistry 34 (10): 2954–2961. doi:10.1021/jm00114a003. PMID 1920349. 
  5. ^ Teuber, Hans-J.; Benz, Siegfried (1967). "Reaktionen mit Nitrosodisulfonat, XXXVI. Chinolin-chinone-(5.6) aus 5-Hydroxy-chinolinen". Chem. Ber. 100 (9): 2918–29. doi:10.1002/cber.19671000916.  Abstract (in German).
    Teuber, Hans-J. (1972), "Use of dipotassium nitrosodisulfonate (Fremy's salt): 4,5-dimethyl-o-benzoquinone", Org. Synth. 52: 88 ; Coll. Vol. 6: 480 
  6. ^ Wertz, J. E.; Bolton, J. R. (1972). Electron Spin Resonance: Elementary Theory and Practical Applications. New York: McGraw-Hill. ISBN 0-07-069454-0.  - See page 463 for information on intensity measurements and page 86 for an EPR spectrum of Fremy's salt.
  7. ^ Zielonka, Jacek, et al. (2005). "Mechanistic similarities between oxidation of hydroethidine by Fremy’s salt and superoxide: Stopped-flow optical and EPR studies". Free Radical Biology & Medicine 39 (7): 853–863;. doi:10.1016/j.freeradbiomed.2005.05.001. PMID 16140206. 
  8. ^ W. Xue et al. (2002), "A metabolic activation mechanism of 7H-dibenzo[C,G]carbozole via 0-quinon. Part 1: synthesis of 7H-dibenzo[C,G]carbozole-3,4-dione and reactions with nucleophiles", Org. Synth. 22: 295–300 
  9. ^ Liu, Z.-L.; Han, Z.-X.; Chen, P.; Liu, Y.-C (1990). "Stopped-flow ESR study on the reactivity of vitamin E, vitamin C and its lipophilic derivatives towards Fremy’s salt in miceller systems". Chem. Phys. Lipids 56 (1): 73–80. doi:10.1016/0009-3084(90)90090-E. PMID 1965427. 
  10. ^ Z.L., Liu, Z.X. Han, P. Chen and Y.C. Liu (1990). "Chem. Phys. Lipid" 56. p. 73. 
  11. ^ a b W. Xue et al. (2002). "A metabolic activation mechanism of 7H-dibenzo[C,G]carbozole via 0-quinon. Part 1: synthesis of 7H-dibenzo[C,G]carbozole-3,4-dione and reactions with nucleophiles". Polycyclic Aromatic Compounds 22 (3): 295–300. doi:10.1080/10406630213597. 
  12. ^ Di Giulio et al. (2000). "EPR study of Fremy’s salt nitroxide reduction by ascorbic acid; influence of bulk pH values". Res. Chem. Intermed 26 (9): 885–896. doi:10.1163/156856700X00372. 
  13. ^ Wehrli, Pius A.; Pigott, Foster (1972), "Oxidation with the nitrosodisulfonate radical. I. Preparation and use of sodium nitrosodisulfonate: trimethyl-p-benzoquinone", Org. Synth. 52: 83 ; Coll. Vol. 6: 1010 
  14. ^ a b http://chemistris.tripod.com/science/synthesis_of_fremys_salt.pdf

Further reading[edit]