Figure 6.

EPR fast-flow spectra of the 2-methoxy-4-methylphenol radical cation produced in a system of 2-methoxy-4-methylphenol, cerium(IV) sulfate, and H₂SO₄ at concentrations in the flat cell of 1.0 mM, 0.9 mM, and 0.225 M, respectively. Oxygen was removed from the reagent solutions by bubbling 99.9999% pure nitrogen gas through them. Equal volumes of 2-methoxy-4-methylphenol and Ce(IV) solutions were mixed milliseconds before they entered the flat cell at a total flow rate of 40 mL/min. The final solution also contained 10% v/v ethanol. (A) Complete system with 2-methoxy-4-methylphenol and Ce(IV). (B) Simulated EPR spectrum with the coupling constants given in Table 1. (C) Residual plot produced when simulated spectrum B is subtracted from experimental spectrum A. EPR spectra were recorded at 20 mW of microwave power, 0.050 mT of field modulation, 6.0 mT of field sweep width, 164 ms time constant, 82 ms conversion time, and 33 scans of 1024 points.