Glycerol Oxidation by Molecular Oxygen in Presence of Novel Supported Platinum Catalysts

Glycerol is a bio-fuel production by-product. This work studies novel supported Pt contained catalyst, prepared by extractive-pyrolytic method [1], activity and selectivity in process of glycerol oxidation in alkaline water solutions. In the process of catalysts preparation the support nature, the time of support dispersion in the precursor solution, drying temperature, temperature and duration of pyrolysis, as well as Pt concentration in the catalyst, were varied. Research revealed that catalysts activity and selectivity depends on catalyst support nature, pyrolysis temperature and duration as well as on Pt concentration in catalyst. The most active catalysts are Pt/AlO(OH), Pt/ZrO2, Pt/Y2O3, Pt/Lu2O3 and Pt/Al2O3. Depending on the catalyst composition and its synthesis conditions main oxidation products obtained were either glyceric or lactic acids The highest selectivity by glyceric acid 55-61% with glycerol conversion 85-90% has been achieved by use of 5%Pt/Al2O3 catalyst prepared from precursor with concentration 0.4 M, support dispersion time 10 min, drying temperature 80-100 ºC and time 10 min, pyrolysis temperature and duration are equal correspondingly 300 ºC and 120 min. Glycerol oxidation conditions: c0(glycerol) = 0.3 M, c0(NaOH) = 0.7- 1.5 M, n(glycerol)/n(Pt) = 210-300, t = 60 ºC, P(O2) = 1 atm, oxidation time is 4-8 hours. The highest selectivity by lactic acid 63% with glycerol conversion 86% has been achieved by use of 1.25%Pt/Y2O3 catalyst prepared from precursor with concentration 0.4 M, support dispersion time 10 min, drying temperature 80-100 ºC and time 3 min, pyrolysis temperature and duration are equal correspondingly 400 ºC and 5 min. Glycerol oxidation conditions: c0(glycerol) = 0.3 M, c0(NaOH) = 1.5 M, n(glycerol)/n(Pt) = 300, t = 60 ºC, P(O2) = 1 atm, oxidation time is 7 hours