. In addition, sulfur was also determined in the aqueous
phase by ICP OES. For experiments with model compounds,
aqueous phase was washed with toluene for characterization of obtained
products. Sulfur conversion efficiency was calculated taking
into account the sulfur concentration remaining in oil phase. Finally,
using all the optimized conditions, it was studied the possibility to
reuse the aqueous phase (H2O2 and acetic acid) to treat fresh
amounts of the feedstock. For comparison, experiments were carried
using the optimized conditions for UAOD process but mechanical
stirring (7000 rpm) was used instead of ultrasound. In this case, reagents
addition, separation of oil and aqueous phase and extraction
were carried as previously optimized for UAOD process. Fig. 1 shows
the overall procedure and the sequence of optimizations performed.