Environmentally benign oxidations of Alkenes and Alcohols to corresponding aldehydes over Anchored Phosphotungstates: Effect of supports as well as oxidants
Sukriti Singh, Anjali Patel*
*Polyoxometalates and Catalysis Laboratory, Department of Chemistry, Faculty of Science, The M. S. University of Baroda, Vadodara-390002, Gujarat, India.
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SUPPLEMENTARY FIGURES:
Supplementary Fig.S1. Oxidation of benzyl alcohol over (PW11)3/MCM-48 using H2O2, a) Effect of mole ratio, b) Effect of Time, and c) Effect of amount of catalyst.
Supplementary Fig.S2. Styrene oxidation with O2 (a, c, e) Optimisation of reaction parameters with (PW11)3/MCM-41 and (b, d, f) Optimisation of reaction parameters with (PW11)3/MCM-48. (a, b) Effect of amount of catalyst: substrate= 100 mmol, 0.2 mmol TBHP, time= 8 h, temp.= 80 oC, (c, d) Effect of time: substrate= 100 mmol, 0.2 mmol TBHP, amount of catalyst= 20 mg, temp.= 80 oC, (e, f) Effect of temperature: substrate= 100 mmol, 0.2 mmol TBHP, amount of catalyst= 20 mg, time= 8 h.
Supplementary Fig.S3.Benzyl alcohol oxidation with O2 (a, c, e) Optimisation of reaction parameters with (PW11)3/MCM-41 and (b, d, f) Optimisation of reaction parameters with (PW11)3/MCM-48. (a, b) Effect of amount of catalyst: substrate= 100 mmol, TBHP= 0.2 mmol, time= 24 h, temp.= 90 oC, (c, d) Effect of time: substrate= 100 mmol, TBHP= 0.2 mmol, amount of catalyst= 25 mg, temp.= 90 oC, (e, f) Effect of temperature: substrate= 100 mmol, TBHP= 0.2 mmol, amount of catalyst= 25 mg, time= 24 h.
Supplementary Fig.S4. Oxidation of styrene/ benzyl alcohol in presence of O2 + Catalyst (red line) and O2 + TBHP + Catalyst (black line) with respect to time.
Supplementary Fig. S5. FT-IR spectra of fresh and recycled catalysts, a)(PW12)3/MCM-41 and b) (PW11)3/MCM-41, c)(PW12)3/MCM-48 and d) (PW11)3/MCM-48.
Supplementary Fig.S6.FT-Raman spectra of fresh and recycled catalysts, a)(PW12)3/MCM-41, b) (PW11)3/MCM-41, c)(PW12)3/MCM-48 and d) (PW11)3/MCM-48.
SUPPLEMENTARY TABLES:
Supplementary Table 1. Optimized conditions for all the reactions.
Conditions / Reactions with different substrates and oxidantsBenzyl alcohol reaction / Styrene reaction
H2O2 / O2 / H2O2 / O2
Mole ratio of substrate to H2O2 / 1:3 / - / 1:3 / -
Substrate Concentration / 10 mmol / 100 mmol / 10 mmol / 100 mmol
Reaction time / 20 h / 24 h / 18 h / 8 h
Catalyst amount / 25 mg / 25 mg / 20 mg / 20 mg
Reaction temperature / 90 oC / 90 oC / 80 oC / 80 oC
Recycling and regeneration study
The catalysts were recycled (Supplementary Table 2) in order to test its activity as well as stability. The catalysts were separated from the reaction mixture only by simple filtration, first washed with (unreacted substrates if any), dichloromethane, followed by distilled water, and then dried at 100 °C, and the recovered catalyst was charged for the further run. As seen in the table, there was no appreciable change observed in conversion and selectivity up to fourth cycle, which shows that the catalysts are stable and can be regenerated for repeated use.
Supplementary Table 2. Recycling study for oxidation of styrene a(PW11)3/MCM-41 and b(PW11)3/MCM-48 under optimized conditions with H2O2.
Catalyst / % Conversion a/b / % SelectivityFresh / 95/98 / 89/88
1st Run / 94/98 / 88/88
2nd Run / 92/97 / 88/87
3rd Run / 92/97 / 85/87
4th Run / 91/95 / 85/87
Styrene: H2O2 1:3, catalyst amount-20 mg, time-18 h, temp. 80 oC.
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