Photochemistry in a heterogeneous system: chlorophyll-sensitized reduction of p-dinitrobenzene by hydrazobenzene

Journal Article · Thu Jan 15 00:00:00 EST 1987 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100286a037· OSTI ID:7100911

Seely, G R; Haggy, G A

The photoreduction of p-dinitrobenzene, sensitized by aqueous suspensions of chlorophyll a with other amphiphiles adsorbed onto polyethylene-tetradecane particles, differs in some respects from the photoreduction in solution. The reaction proceeds in two stages. The products of the first stage, N-(p-nitrophenyl)hydroxylamine and azobenzene, are separated into the aqueous and hydrocarbon particle phases, respectively. The nature of the second stage of reaction is uncertain, but observations are best explained by a reduction of N-(p-nitrophenyl)hydroxylamine to 4,4'-dinitrohydrazobenzene. The quantum yield of photoreduction to the hydroxylamine does not seem to correlate at all with quantum yield of fluorescence of the sensitizing particles. This and the relative magnitudes of the yields suggest that the principal photochemical reaction is reduction of dinitrobenzene not by the excited singlet state of chlorophyll or by the triplet state formed directly by intersystem crossing but by high-energy ion pair states or perhaps triplets formed from them by decay. Absorption spectrometry in the heterogeneous system is complicated by superposition of the so-called sieve effect on the path-length enhancement effect of the highly scattering system. The role of the interface between the particle and aqueous phases on the course of the reaction is discussed.

• Research Organization: Battelle-Kettering Lab., Yellow Springs, OH
• DOE Contract Number: FG02-84ER13187
• OSTI ID: 7100911
• Journal Information: J. Phys. Chem.; (United States), Vol. 91:2
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
BENZENE
PHOTOCHEMICAL REACTIONS
CHLOROPHYLL
CATALYTIC EFFECTS
KETONES
ORGANIC NITROGEN COMPOUNDS
ABSORPTION SPECTROSCOPY
EXPERIMENTAL DATA
FLUORESCENCE
PHOTOCHEMISTRY
REDUCTION
VISIBLE SPECTRA
AROMATICS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHEMISTRY
DATA
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
LUMINESCENCE
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
SPECTRA
SPECTROSCOPY
400500* - Photochemistry