Figure 4.

EPR fast-flow spectra of the 3,4-dimethoxytoluene radical cation produced in a system of 3,4-dimethoxytoluene, 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 3,4-dimethoxytoluene and Ce(IV) solutions were mixed milliseconds before entering the flat cell at a total flow rate of 20 mL/min. The final solution also contained 10% v/v ethanol. (A) Complete system with 3,4-dimethoxytoluene 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 microwave power, 0.025 mT field modulation, 6.0 mT field sweep width, 1.3 s time constant, 655 ms conversion time, and 36 scans of 1024 data points.