Green Chemistry
Paper
with the photovoltage controlled by a regulator. The reaction
lasted 2–6 hours, and the (constant photopotential) electrolysis
was terminated and as the electrolysis reaction progresses and
toluene is consumed the photocurrent decreases tenfold. After
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Product analysis
Subsequent to STEP electrolysis the products were identified
by UV/Vis and FTIR and the content of product and inter-
mediates (benzyl alcohol, benzaldehyde) determined quanti-
tatively by Gas Chromatograph. IR-spectra were measured in
KBr pellets from 4000–400 cm−1 using a Tensor 27 FTIR
Spectrometer.43 UV-Vis Spectra samples were measured in
sulfuric acid using a 1 cm path length quartz cell at room
temperature with a UV-1700 Shimadzu Spectrophotometer
using Cary Win UV Scan software. The reaction yield (in
percent) was calculated by comparing the initial moles of
toluene to the measured moles of either benzoic acid or inter-
mediates produced in the electrolysis. After a stabilization
period of 2 h, liquid products were collected and analyzed
using a gas chromatograph (GC-14C Shimadzu) installed with
a flame ionization detector and a 30 m × 0.25 mm × 0.33 μm
FFAP capillary column. The selectivity of benzoic acid (in
percent) was determined by comparing the moles of benzoic
acid produced to total moles (of intermediates and benzoic
acid) produced.
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Acknowledgements
The research is financially supported by National Science
Foundation of China (grant no. 21376049, 21306022) and the
United States National Science Foundation (grant no. 123072).
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