Influence of added water on pathways and efficiency of photocatalytic reactions in ethanol solutions of titanium tetrachloride

Journal Article · Tue Jul 01 04:00:00 EDT 1986 · Theor. Exp. Chem. (Engl. Transl.); (United States)

DOI:https://doi.org/10.1007/BF00525304· OSTI ID:6214078

Kryukov, A I; Kuchmii, S Ya; Korzhak, A V; Korol', A N

Electronic spectroscopy, ESR, and gas-liquid chromatography have been used in studying the action of light with lambda = 254 nm on ethanol-water solutions of titanium tetrachloride. It has been established that, in the course of irradiation, a photocatalytic process develops with the participation of coordination compounds of titanium(IV) and (III), resulting in oxidation and breakdown of the ethanol to form acetaldehyde, methane, ethane, ethyl chloride, and molecular hydrogen. In the presence of small amounts of added water (up to 0.5 M), the efficiency of CH/sub 4/ and C/sub 2/H/sub 6/ formation is much lower but the yield of H/sub 2/ is higher, in comparison with the yields of these products in absolute ethanol. With further increases in the water concentration, the rates of formation of methane, ethane, and acetaldehyde increase. The maximum quantum yields (..sigma..) are as follows: ..sigma..(CH/sub 4/) = 1.8 x 10/sup -4/ and ..sigma..(C/sub 2/H/sub 6/) = 1 x 10/sup -3/ in absolute ethanol; ..sigma..(CH/sub 3/CHO) = 1.6 x 10/sup -2/ in ethanol with the addition of 6.0 M H/sub 2/O; ..sigma..(H/sub 2/) = 6.7 x 10/sup -3/ in solutions containing 0.5 M H/sub 2/O. The observed differences in the product yields are explained by a change in the composition and structure of the titanium compounds that act as the photocatalyst, a change that takes place when the water concentration is varied. A mechanism is proposed for these reactions.

• Research Organization: L. V. Pisarzhevskii Institute of Physical Chemistry, Kiev, USSR
• OSTI ID: 6214078
• Journal Information: Theor. Exp. Chem. (Engl. Transl.); (United States), Journal Name: Theor. Exp. Chem. (Engl. Transl.); (United States) Vol. 22:1; ISSN TEXCA
• Country of Publication: United States
• Language: Russian

Related Subjects

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10 SYNTHETIC FUELS
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
ACETALDEHYDE
ACTIVATION ENERGY
ALCOHOLS
ALDEHYDES
ALKANES
AQUEOUS SOLUTIONS
CATALYSIS
CATALYTIC EFFECTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTION YIELD
CHEMICAL REACTIONS
CHLORIDES
CHLORINE COMPOUNDS
COMPLEXES
DECOMPOSITION
DISPERSIONS
EFFICIENCY
ELECTRON TRANSFER
ELEMENTS
ENERGY
ENERGY EFFICIENCY
ETHANE
ETHANOL
HALIDES
HALOGEN COMPOUNDS
HOMOGENEOUS CATALYSIS
HYDROCARBONS
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN PRODUCTION
HYDROXY COMPOUNDS
KINETICS
METHANE
MIXTURES
NONMETALS
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PRODUCTION
REACTION KINETICS
SOLUTIONS
TITANIUM CHLORIDES
TITANIUM COMPLEXES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
WATER
YIELDS