Catalysis of Organic..

200 Fructose HydrogenationTable 1. The affect of temperature on the percentages of fructose’s tautomers (5).°C%α-Pyr%β-Pyr%α-Fur%β -Fur%OpenKeto%FurFur/PyrFurβ / αOverallβ / α0 0 85 4 11 0 15 0.18 2.75 24.030 2 70 5 23 0 28 0.39 4.6 13.380 2 53 10 32 3 42 0.76 3.2 7.08Pyr => Pyranose. Fur => FuranoseMax Act., mol/(min·mol metal)1,81,61,41,210,80,60,40,20Figure 2NiMo doped NiCu FT at 25°CCu FT at 80°CPt doped CuFe doped Cu0 25 50 75 100 125 150mmol Formaldehyde / mol Active MetalFigure 2. The effects of the FT level on the catalysts’ activity.Figure 3. The effects of the FT level on the catalysts’ % mannitol selectivity.Mannitol Selectivity%66625854Figure 4NiMo doped NiCuPt doped CuFe doped CuNi - FTMo doped Ni - FTCu - FT at 25°CCu - FT at 80°C50Only for the not FT46 y = -10,71x + 64,643R 2 = 0,9623420 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8Max Activity, mol/(min·mol metal)Figure 4. The relationship between maximum activity and % mannitol.Figure 5. The relationship between activation energy and % mannitol.of the Ni catalyst as it went through an optimum at ~48.2 mmol of formaldehyde permol of Ni implying that there is an optimal ensemble size for this polyol. The initialFT of the Mo doped Ni had the largest mannitol selectivity increase of all of thetreated catalysts and it was just as selective as the not FT Ni catalyst. This suggeststhat formaldehyde selectively decomposes on Mo to give a surface with a similarfructose activity and selectivity profile as one without Mo. There could also be anoptimum FT level for the Mo doped Ni and this behavior mirrors that of the Nicatalysts. The trend seen in Figure 4 for the not FT catalysts shows that mannitolselectivity increases with lower activity and this is also true for the lower levels of%Mannitol Selectivity%Mannitol Selectivity6864605652484466625854504642Figure 3NiMo doped NiCu FT at 25°CCu FT at 80°CPt doped CuFe doped Cu0 25 50 75 100 125 150mmol Formaldehyde / mol Active MetalFor only the not FTy = 0,1928x + 37.571R 2 = 0,978Figure 5NiMo doped NiCuPt doped CuFe doped CuNi - FTMo doped Ni - FTCu - FT at 25°CCu - FT at 80°C0 50 100 150 200 250 300 350 400 450Activation Energy, KJ/mol