9140. TEMPO

Nomenclature

CAS number: 2564-83-2
2,2,6,6-Tetramethyl-1-piperidinyloxy; 2,2,6,6-tetramethylpentamethylene nitroxide.
C9H18NO; mol wt 156.25.
C 69.18%, H 11.61%, N 8.96%, O 10.24%.

Description and references

Stable nitroxide free radical used as reversible capping agent in “living” free radical polymerizations and as catalyst for selective oxidation of alcohols. Prepn: E. G. Ruzantsev et al., Bull. Acad. Sci. USSR Div. Chem. Sci. 1962, 2152. Crystal structure: Z. Ciunik, J. Mol. Struct. 412, 27 (1997). Thermal stability: M. V. Ciriano et al., J. Am. Chem. Soc. 121, 6375 (1999). Effect of acids on reaction rates: M. V. Baldovi et al., Macromolecules 29, 5497 (1996). Use in oxidation of alcohols: M. Zhao et al., J. Org. Chem. 64, 2564 (1999); in production of aminyl radicals: W. Huang et al., J. Am. Chem. Soc. 121, 3939 (1999); in polymerization: L. I. Gabaston et al., Polymer 40, 4505 (1999).

Chemical structure

Properties

Monoclinic dark red crystals, mp 36-40°. Flash pt: 67°C (Acros Organics Data Sheet).

Use

In organic chemistry as a radical trap, a catalyst and in polymerization mediation.