# Sulfonic Resins as Catalysts for the Oxidation of Alcohols with H\({}_{2}\)O\({}_{2}\)/KBr
## 3 Materials and Methods
Nuclear magnetic resonance (NMR) spectroscopy was carried out with a Bruker Avance 400 (\({}^{1}\)H NMR 400 MHz, \({}^{13}\)C NMR 100 MHz) and the chemical shifts were expressed in ppm. Deuterated chloroform (CDCl\({}_{3}\)) was used as both the solvent and reference (7.26 ppm for \({}^{1}\)H, 77.0 ppm for \({}^{13}\)C). Methyl 9(10)-hydroxysterate (**1a + 1b**) was prepared via sequential epoxidation-hydrogenolysis [7]: methyl oleate was epoxidized with _tert_-butyl hydroperoxide (TBHP) in trifluorotoluene (TFT) at 120 \({}^{\circ}\)C using a Ti-SiO\({}_{2}\) catalyst (prepared from Merck silica and CP\({}_{2}\)TiCl\({}_{2}\) as previously described [6]). The catalyst was filtered and washed with CH\({}_{2}\)Cl\({}_{2}\), and the filtrate was evaporated under reduced pressure. The methyl _cis_-9,10-epoxystearate was used without further purification. A 10 mL Buchi reactor was charged with 500 mg of methyl _cis_-9,10-epoxystearate (1.6 mmol), 5 mL of 2,2-trifluoroethanol and 120 mg of Pd/C (wet with 50 wt% water, 10 wt% Pd of dry solid, 0.056 mmol Pd, 3.5 mol%). The reactor was filled with H\({}_{2}\) (5 bar) and the mixture was stirred at 65 \({}^{\circ}\)C for 6 h. The catalyst was filtered off and washed with CH\({}_{2}\)Cl\({}_{2}\). Methyl 9(10)-hydroxysterate was purified via column chromatography on silica with AcOEt/hexanes (1:9) as the eluent. Methyl 9(10)-hydroxysterate (**1a + 1b**): \({}^{1}\)H NMR (8 ppm, CDCl\({}_{3}\), 400 MHz): 3.65 (s, 3H), 3.62-3.54 (m, 1H), 2.29 (t, 2H, \(J\) = 7.6 Hz), 1.64-1.57 (m, 2H), 1.45-1.27 (m, 2H), 0.87 (t, 3H, \(J\) = 7.6 Hz); \({}^{13}\)C NMR (8 ppm, CDCl\({}_{3}\), 100 MHz): 17.4, 71.11, 71.09, 51.5, 37.64, 37.59, 37.56, 34.23, 34.21, 32.02, 29.85, 29.77, 29.75, 29.73, 29.71, 29.61, 29.53, 29.45, 29.41, 29.34, 29.31, 29.24, 29.20, 25.79, 25.74, 25.69, 25.06, 25.04, 24.0, 22.8, 14.2. General procedure of oxidation: KBr (12 mg, 0.1 mmol), Dowex 50W\(\times\)8 (22.2 mg, 0.1 mmol of sulfonic groups) and H\({}_{2}\)O\({}_{2}\) (60%, 34 mL, 0.75 mmol) were added to a solution of methyl 9(10)-hydroxysterate (**1a + 1b**), 157.3 mg, 0.5 mmol) in 1 mL of CH\({}_{2}\)Cl\({}_{2}\)/H\({}_{2}\)O (9:1 \(v/v\)). The mixture was stirred at room temperature and monitored via GC. After 24 or 48 h, the catalyst was filtered and washed with CH\({}_{2}\)Cl\({}_{2}\). The filtrate was washed with distilled water (3 \(\times\) 10 mL) and dried with anhydrous MgSO\({}_{4}\); then, the solvent was evaporated under vacuum and the methyl 9(10)-oxostearate was identified via NMR. In the recycling \begin{table}
\begin{tabular}{l l c c c c c} \hline \hline
**Sulfonic Solid** & **Physical Form** & \multicolumn{4}{c}{**Particle Size (mm)**} & \multicolumn{2}{c}{**Acid Functionalization 1**} \\  & **Supplier** & **Dry 2** & **Swellen 2** & **Supplier** & **Experim. 3** \\ \hline Aquivion PW79S [33] & Powder & n.r. & n.d. & n.d. & 1.23 to 1.30 & 1.26 \\ Nafion NR50 [34] & Pellets & 3 \(\times\) 4 & \(\approx\)3 & \(\approx\)4 & \(>\)0.92 & 0.89 \\ Aquivion P98 [35] & Pellets & n.r. & \(\approx\)2 & \(\approx\)3.5 to 4 & 0.98 to 1.06 & 0.98 \\ Amberlyst 15 [36] & Beads & \(<\)0.3 & \(\approx\)0.5 & \(\approx\)0.8 & 4.7 & 4.40 \\ Dowex 50W\(\times\)8 [37] & Beads & & & (1.7) 4  & 4.46 \\ Dowex 50W\(\times\)2 [38] & Beads & 0.075 to 0.15 & n.d. & n.d. & (0.6) 5  & 4.45 \\ \hline \hline \end{tabular}  
* Functionalization in mmol of sulfonic groups per gram. 2 From pictures in Supporting Material. Resins were swollen in CH\({}_{2}\)Cl\({}_{2}\)/H\({}_{2}\)O (9:1 \(v/v\)). 3 Titration of the resulting acidic solution obtained after passing 2.0 M NaCl through a resin bed. 4 Wet resin at 1.7 mmol per mL (50–58 wt% water). 5 Wet resin at 0.6 mmol per mL (74–82 wt% water).  
\end{table} 
Table 5: Properties of the sulfonic resins used in this work 1.  
experiments, the resin was left to decant, the uppernadant was separated using a pipette, and the catalyst was washed with distilled water and then dried under vacuum at 120 \({}^{\circ}\)C overnight prior to reuse.