The first ESR observation of radical species in subcritical water

Tetrahedron

Volumn 65, Issue 4, 2009, Pages 807-810

  Kobiro, Kazuya ^a   Matsura, Masahiko ^a   Kojima, Hiroyuki ^a   Nakahara, Koichi ^b  

^a KOCHI UNIVERSITY OF TECHNOLOGY   (Japan)

^b SUNTORY LTD   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

BENZYL ALCOHOL DERIVATIVE; HYDROGEN; TRITYL DERIVATIVE; WATER;

ARTICLE; ELECTRON SPIN RESONANCE; HIGH TEMPERATURE; PRESSURE MEASUREMENT; PRIORITY JOURNAL;

EID: 57649096929     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tet.2008.11.074     Document Type: Article

References (31)

1. For review, see:. Akiya N., and Savage P.E. Chem. Rev. 102 (2002) 2725-2750 and references cited therein
2. Yao J., and Evilia F. J. Am. Chem. Soc. 116 (1994) 11229-11233
3. Ikushima Y., Hatakeda K., Sato O., Yokoyama T., and Arai M. J. Am. Chem. Soc. 122 (2000) 1908-1918
4. Tsujino Y., Wakai C., Matsubayashi N., and Nakahara M. Chem. Lett. 28 (1999) 287-288
5. Ikushima Y., Hatakeda K., Sato O., Yokoyama T., and Arai M. Angew. Chem., Int. Ed. 40 (2001) 210-213
6. Zhang R., Zhao F., Sato M., and Ikushima Y. Chem. Commun. (2003) 1548-1549
7. Itami K., Terakawa K., Yoshida J.-i., and Kajimoto O. J. Am. Chem. Soc. 125 (2003) 6058-6059
8. Comisar C.M., and Savage P.E. Green Chem. 7 (2005) 800-806
9. Nolen S.A., Liotta C.L., Eckert C.A., and Gläser R. Green Chem. 5 (2003) 663-669
10. Arita T., Nakahara K., Nagami K., and Kajimoto O. Tetrahedron Lett. 44 (2003) 1083-1086
11. Wang P., Kojima H., Kobiro K., Nakahara K., Arita T., and Kajimoto O. Bull. Chem. Soc. Jpn. 80 (2007) 1828-1832
12. Takahashi H., Hisaoka S., and Nitta T. Chem. Phys. Lett. 363 (2002) 80-86
13. Takahashi H., Hashimoto H., and Nitta T. J. Chem. Phys. 119 (2003) 7964-7971
14. Bühler W., Dinjus E., Ederer H.J., Kruse A., and Mas C. J. Supercrit. Fluids 22 (2002) 37-53
15. Rice S.F., and Steeper R.R. J. Hazard. Mater. 59 (1998) 261-278
16. Lee G., Nunoura T., Matsumura Y., and Yamamoto K. Ind. Eng. Chem. Res. 41 (2002) 5427-5431
17. Feng J., Aki S.N.V.K., Chateauneuf J.E., and Brennecke J.F. J. Am. Chem. Soc. 124 (2002) 6304-6311
18. Yim B., and Maeda Y. Chem. Lett. 31 (2002) 452-453
19. Schneider G.M. Ber. Bunsen-Ges. Phys. Chem. 76 (1972) 325-331
20. Dewar M.J.S., Zoebisch E.G., Healy E.F., and Stewart J.J.P. J. Am. Chem. Soc. 107 (1985) 3902-3909
21. Klamt A., and Schüürmann G.Z. J. Chem. Soc., Perkin Trans. 2 (1993) 799-805
22. Maki A.H., Allendoerfer R.D., Danner J.C., and Keys R.T. J. Am. Chem. Soc. 90 (1968) 4225-4231
23. Same products, 2, 3, and 4, were obtained in both sub-CW and SCW as shown in Table 2. Taking into account that physical properties of sub-CW and SCW, such as density, polarity, and ion product, change continuously between sub-CW and SCW in accordance with the temperature, we think it would be possible to discuss the reaction mechanism in sub-CW and SCW conditions in the same manner.
24. Asher S.E., Browne S.E., Cornwall E.H., Frisoli J.K., Salot E.A., Sauter E.A., Trecoske M.A., and Veale Jr. P.S. J. Am. Chem. Soc. 106 (1984) 1432-1440
25. Two electron transfer followed by proton shift from hydrogen donor, 5 or 6, to 1 could be possible to afford the reduction product, however the calculated energies (AM1) necessary for the first electron transfer processes from 5 and 6 to 1 are quite larger (183 and 165 kcal/mol, respectively) than the bond dissociation energy for the homolytic fission of 1 (46 kcal/mol, Scheme 1).
26. When alcohol 4 was treated in SCW (420 °C, 30 min, 0.35 g/mL water density), 41% of 3 along with 48% recovery of 4 were obtained. Although the reaction pathway to give 4 from 1 is not clear yet, 4 could be derived from 3 by attack of the generated hydroxyl radical two times.
27. Formation of benzopinacol could be possible, if the reaction proceeds via the radical species. When benzopinacol was exposed to high-temperature (250 °C, GC measurement), disproportionation occurred to give almost equal amounts of benzophenone (7) and benzhydrol. Judging from this result, benzopinacol cannot be stable under the reaction conditions even if it is formed by coupling of two diphenylhydroxymethyl radicals in the reaction.
28. Tucker S.C., and Maddox M.W. J. Phys. Chem. B 102 (1998) 2437-2453
29. Coupling products of radicals such as biphenyl and tetraphenylmethane were not detected. The water cage could prevent the two radical species from meeting together to give the coupling products.
30. Miyagawa N., Karatsu T., Futami Y., Kunihiro T., Kiyota A., and Kitamura A. Bull. Chem. Soc. Jpn. 69 (1996) 3325-3329
31. Shi M., Okamoto Y., and Takamuku S. J. Chem. Res., Synop. (1990) 346-347