2-Hydroxy-2-propyl radical, signal

By varying the amount of chloroformste added per gram dextran different degrees of activation and derivatives of variable carbamate content could be prepared. In the NMR spectrum of the reaction product (IX) the methyl protons of the 2-hydroxy propyl radicals show up as a doublet at 6 = 1,3 ppm. From the integration values of the NMR signals the degree of modification was calculated. 

The data shown in Scheme 12.7 confirm that addition of (substituted) benzoyl radicals is slower than that of counter radicals (Scheme 12.7b), and therefore the benzoyl adducts have weak signals in the TR ESR spectra. A similar conclusion was obtained by FT TR ESR study of the photolysis of IRG2959 in the presence of NBA (Schemes 12.1 and 12.3)." ° ESR signals of two products of photolysis of IRG2959, namely, 2-hydroxy-2-propyl radical and substimted benzoyl radical, demonstrate quite different time dependences in the presence of acrylate. The signal of 2-hydroxy-2-propyl radical disappears faster with an increase in acrylate concentration, whereas benzoyl radical is practically unaffected by the presence of acrylate in concentrations up to 0.1 M." ° However, one can obtain only estimations of kinetic rate constants A add... 

Trifunac et al. measured CIDEP spectra for the photoreduction of benzophenone (Ph2CO) in 2-propanol [7] as shown in fig. 5-5. The spectra are composed of the signals due to the two different radicals, the 2-hydroxy-2-propyl (signals 2 in fig. 5-5) and benzophenone ketyl (signal 1 in this figure) radicals. These radicals are produced by the following reactions ... 

Fig. 10-11. CIDEP spectrum observed at a delay time of 0.25 ps after laser excitation of a 2-propanol solution of PhsP at room temperature. Stick diagrams a and b indicate the signal positions due to the 2-hydroxy-2-propyl and diphenylphosphinyl radicals, respectively. (Reproduced from Ref. [7] by permission from Elsevier Science B. V.)...

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See also in sourсe #XX -- [ ]

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