Original Pt-Sn/Al2O3 catalyst for selective hydrodeoxygenation of vegetable oils

Highlights: • Hydrodeoxygenation of rapeseed oil to alkanes selectivity reaches up to 90%. • Original precursor (PPh4)3[Pt(SnCl3)5] was used for catalyst synthesis. • Intermetallic alloy PtSn3 clusters formation causes high selectivity of the catalyst. • Different active sites for hydrodeoxygenation and decarboxylation/decarbonylation. -- Abstract: The preparation of biodiesel from fatty materials HDO provides a very constructive idea to solve the global clean energy problem. The application of catalytic technology to convert oils into green liquid hydrocarbon fuel has great potential for industrial application. The main problem with the development of green diesel technology is the limited number of available non-food sources of fatty acid triglycerides. Also the researchers have made remarkable achievements in the field of catalyst, the stability of the catalyst is insufficient and the selectivity of large molecules of direct alkanes is low. These defects hinder the large-scale resource development of biodiesel. In current paper the potential of hydrodeoxygenation (HDO) of fatty materials and model esters was explored by enhancing the synergy of platinum and tin by using heterometallic (PPh₄)₃ [Pt (SnCl₃)₅ complex. Heterometallic (PPh₄)₃ [Pt (SnCl₃)₅] complex provides in its structure platinum and tin atoms linked by a metal–metal bond that causes the originality of catalytic performance. The performance of bimetallic Pt-Sn/Al₂O₃ catalyst, which is characterized by the Sn/Pt molar ratio of 5/1, has been studied at hydrogen pressure 50 atm and temperature 400–480 °C. HDO reaction of a number of fatty materials has been shown to proceed with the highest ever yield of direct hydrocarbons derived from alkoxy and acyl groups of the initial ester. Also it was investigated a performance in HDO reaction of mixture containing rapeseed oil oleic acid and water that simulate cooked oil that may be a prospective soure for green hydrocarbons in megalopolises. A structural studies of the catalyst showed that its high selectivity in HDO reaction of fatty materials provided by two important factors: impregnated particles size and formation of intermettallic species of PtSn_3±σ. Finally, catalysts sustained activity and stability were tested during five turns of 24 h each.