Matrix isolation infrared spectroscopic and density functional study of the mechanism of the oxidation of CH3OH by CrCl2O2

The matrix isolation technique has been employed to isolate several intermediates, in sequence, in the oxidation of CH3OH by CrCl2O2. Consistent with previous theoretical calculations, a hydrogen-bonded complex formed initially after twin jet deposition and was enhanced by matrix annealing to 33 K. This complex was photodestroyed by Hg are irradiation with lambda < 500 nm, and led to the production of HCl and ClCrO2OCH3. These species were also produced by room temperature reaction of the two precursors in a flow system followed by rapid matrix trapping. Heating the flow reaction zone above 150 degrees C led to destruction of ClCrO2OCH3, and production of CH2O and HCl. Above 250 degrees C bands due to CH2O were destroyed and bands due to CO and CO2 grew in. High-level density functional calculations (B3LYP/6-311G*) were carried out to identify potential intermediates in this system and to provide theoretical vibrational spectra for comparison to experiment.