Radiation Induced Incorporation of CO in Pure and Aqueous Methanol

Pure and aqueous methanol were used for radiation induced incorporation of CO at elevated pressure (up to 15 bar). The initial yields (G_i) of the main products in pure methanol under 15 bar CO and 1 bar N₂O were found to be: G_i(formaldehyde) = 3.80 and G_i(glycolic aldehyde) = 2.0. For aqueous (10^-2 mol · dm^-3) methanol under 15 bar CO (dose: 0.557 kGy, pH = 2): the yields were G(formaldehyde) = 5.44, G(glycolic aldehyde) = 4.0 and G(oxalic acid) = 7.7. At pH = 7 the yields were essentially lower, namely: G(formaldehyde) = 3.2, G(glycolic aldehyde) = 2.0, G(formate) = 3.8 and G(oxalate) = 5.0. Probable reaction-mechanisms for the product formation are discussed.