skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Hydrogen-transfer and charge-transfer in photochemical and radiation induced reactions. Progress report, November 1, 1975--October 31, 1976

Abstract

The relative importance of light absorption, quenching of triplet, and hydrogen transfer repair has been examined in retardation by mercaptans of photoreduction of aromatic ketones by alcohols. In the reduction of benzophenone by 2-propanol, retardation is efficient and, after correction for the first two effects, is due entirely to hydrogen-transfer repair, as indicated by deuterium labeling. In reduction of acetophenone by ..cap alpha..-methylbenzyl alcohol, repair by hydrogen transfer is also operative. In reduction of benzophenone by benzhydrol, retardation is less efficient and is due to quenching, as the ketyl radical does not abstract hydrogen from mercaptan rapidly in competition with coupling. Deuterium isotope effects are discussed in terms of competitive reactions. Photoreduction of benzophenone by 2-butylamine and by triethylamine is retarded by aromatic mercaptans and disulfides. Of the retardation not due to light absorption and triplet quenching by the sulfur compounds, half is due to hydrogen-transfer repair, as indicated by racemization and deuterium labeling. The remainder is attributed to quenching by the sulfur compound of the charge-transfer-complex intermediate. Photoreduction by primary and secondary amines, but not by tertiary amines, is accelerated by aliphatic mercaptans. The acceleration is attributed to catalysis of hydrogen transfer by the mercaptan in the charge-transfer complex.more » The effect is large in hydrocarbon solvent, less in polar organic solvents and absent in water.« less

Authors:
Publication Date:
Research Org.:
Brandeis Univ., Waltham, Mass. (USA)
OSTI Identifier:
7248980
Report Number(s):
COO-3118-11
TRN: 77-001304
DOE Contract Number:  
EY-76-S-02-3118
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BENZOPHENONE; CHEMICAL RADIATION EFFECTS; PHOTOLYSIS; DEUTERIUM; ISOTOPE EFFECTS; AMINES; CHEMICAL REACTION KINETICS; THIOLS; CHEMICAL REACTIONS; CHEMISTRY; DECOMPOSITION; HYDROGEN ISOTOPES; ISOTOPES; KETONES; KINETICS; LIGHT NUCLEI; NUCLEI; ODD-ODD NUCLEI; ORGANIC COMPOUNDS; ORGANIC SULFUR COMPOUNDS; PHOTOCHEMICAL REACTIONS; RADIATION CHEMISTRY; RADIATION EFFECTS; REACTION KINETICS; STABLE ISOTOPES; 400600* - Radiation Chemistry; 400500 - Photochemistry; 400302 - Organic Chemistry- Isotope Effects- (-1987)

Citation Formats

Cohen, S.G. Hydrogen-transfer and charge-transfer in photochemical and radiation induced reactions. Progress report, November 1, 1975--October 31, 1976. United States: N. p., 1976. Web. doi:10.2172/7248980.
Cohen, S.G. Hydrogen-transfer and charge-transfer in photochemical and radiation induced reactions. Progress report, November 1, 1975--October 31, 1976. United States. doi:10.2172/7248980.
Cohen, S.G. Fri . "Hydrogen-transfer and charge-transfer in photochemical and radiation induced reactions. Progress report, November 1, 1975--October 31, 1976". United States. doi:10.2172/7248980. https://www.osti.gov/servlets/purl/7248980.
@article{osti_7248980,
title = {Hydrogen-transfer and charge-transfer in photochemical and radiation induced reactions. Progress report, November 1, 1975--October 31, 1976},
author = {Cohen, S.G.},
abstractNote = {The relative importance of light absorption, quenching of triplet, and hydrogen transfer repair has been examined in retardation by mercaptans of photoreduction of aromatic ketones by alcohols. In the reduction of benzophenone by 2-propanol, retardation is efficient and, after correction for the first two effects, is due entirely to hydrogen-transfer repair, as indicated by deuterium labeling. In reduction of acetophenone by ..cap alpha..-methylbenzyl alcohol, repair by hydrogen transfer is also operative. In reduction of benzophenone by benzhydrol, retardation is less efficient and is due to quenching, as the ketyl radical does not abstract hydrogen from mercaptan rapidly in competition with coupling. Deuterium isotope effects are discussed in terms of competitive reactions. Photoreduction of benzophenone by 2-butylamine and by triethylamine is retarded by aromatic mercaptans and disulfides. Of the retardation not due to light absorption and triplet quenching by the sulfur compounds, half is due to hydrogen-transfer repair, as indicated by racemization and deuterium labeling. The remainder is attributed to quenching by the sulfur compound of the charge-transfer-complex intermediate. Photoreduction by primary and secondary amines, but not by tertiary amines, is accelerated by aliphatic mercaptans. The acceleration is attributed to catalysis of hydrogen transfer by the mercaptan in the charge-transfer complex. The effect is large in hydrocarbon solvent, less in polar organic solvents and absent in water.},
doi = {10.2172/7248980},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1976},
month = {10}
}