2-Methyl-2-nitrosopropane (MNP or t-nitrosobutane) is the organic compound with the formula (CH3)3CNO. It is a blue liquid that is used in chemical research as a spin trap, i.e. it binds to radicals.
It is prepared by oxidation of (CH3)3CNH2 using hydrogen peroxide in the presence of sodium tungstate as a catalyst. The freshly distilled compound is a blue volatile liquid. Like other nitroso compounds, it features a bent C-N=O linkage. Upon standing at room temperature, the blue liquid converts to the colourless solid that is the dimer (m.p. 74-75 °C). In solution, this dimer quickly reverts to the blue monomer.
It can be used as a spin trap. This molecule traps unstable free radicals to form stable paramagnetic nitroxide radicals that can be detected and analyzed by electron spin resonance spectroscopy. It is particularly useful for trapping carbon-centered tyrosyl radicals.
MNP is also an efficient regulator of the radical polymerization of methyl methacrylate through the 'pseudoliving' chain mechanism.