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Acetonitrile (CH 3 CN), methanol (CH 3 OH), trichloroethylene (C 2 HCl 3 , TCE), and methylene chloride (CH 2 -Cl 2 ) were degraded in stirred batch reactors in the presence of O 2 at room temperature over films of pristine P-25 TiO 2 under irradiation centered at 360 nm. Molarities of organics, activities of O 2 , irradiation flux, deployment of catalyst, and reactor configuration were matched for vaporized and aqueous organics. The dependence of initial rates and the photoefficiencies of removal on concentrations of reactants and photon flux were measured. Identities and rates of formation and decay of some intermediates were determined. Langmuir coefficients were determined for dark adsorption of the organic vapors on films of P-25 in the presence of dry and water-saturated air. Surface concentrations in equilibrium with aqueous solutions in the dark were calculated with the aid of Henry's law constants from the Langmuir coefficients of the water-saturated vapors. Initial rates of removal of all four compounds from the vapor phase were much higher than from aqueous solution. Initial photoefficiencies of g1 molecule removed per incident photon were observed with vaporized CH 3 OH and TCE in dry air. Water vapor strongly inhibited the conversion of CH 3 OH and CH 2 Cl 2 . CH 3 CN, TCE, and CH 2 Cl 2 vapors appeared to react with both electrons and holes, and homolytic dissociation of the C-C and C-Cl bonds of CH 3 CN and CH 2 Cl 2 appeared to occur.

The reactivity and sites of attack of hydroxyl radicals on simple amides in aqueous solution were studied. The following amides were examined: formamide (F), N-methylformamide (NMF), N,N-dimethylformamide (DMF), acetamide (A), N-methylacetamide (NMA), and , -dimethylacetamide (DMA). The rate constants for reaction of OH radical with NMF, DMF, NMA, and DMA fall in the range (1.0-3.5) X 109 M~l sec-1, but the reactivity with F and A is significantly lower. The absorption spectra in the wavelength range 225-600 nm and the specific rates of decay of the transient species produced by the reaction of OH radicals with amides were determined and their structures assigned. With F and A, OH radicals attack at both sites on the molecule to give HCOÑH, CONH2, CH3COÑH, and CH2CONH2 radicals. With the N-methylated amides, abstraction by OH radicals takes place mainly from the N-methyl group, e.g., OH + CH3CON(CH3)2 -CH3CON(CH2)(CH3) + H20. The implications of these results with respect to the radiolysis of peptides are discussed.

H2 and NH3 were produced when a suspension of Fe203 catalyst particles or sintered pellets in water were illuminated with light of energy greater than 2.3 eV. Catalytic action was demonstrated by detecting H2 yields many times the stoichiometric equivalent of the measured (by X-ray diffraction, Móssbauer spectroscopy, and oxidimetry) Fe(II) content of the catalyst, up to 80X for H2 and 20X for NH3. The initial rate of formation of H2 was 40 µ /h-g of catalyst and of NH3 was 10 µ /h-g of catalyst. The formation

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