Hydrogenolysis of Sorbitol over Ni and Pt loaded on NaY M.Banu 4thAnnual Day 01.08.2010

Biodegradable plastics Introduction Cellulosic biomass is abundant on earth, and is an ideal feedstock for the production of bio-based chemicals. In a simple processing scheme, cellulose is hydrolyzed into simple sugars, then hydrogenated to the sugar alcohols that are further transformed into valuable chemicals. Cellulose glucose Bioethanol PG, EG Antifreeze Sorbitol Glycerol Plastics L-Sorbose Vitamins Lactic acid Biodegradable plastics

Continued... Hydrogenolysis of sorbitol (obtained from glucose) can be used to produce valuable chemicals like ethylene glycol, which are generally produced by multi-step transformations from non-renewable petroleum based feed-stocks. The transformation of carbohydrates from renewable sources into value added chemicals has assumed significance at present owing to the decreasing petroleum reserves and increasing carbon accumulation in the atmosphere. We report our studies on the use of Ni and Pt loaded on NaY as catalysts for the hydrogenolysis of sorbitol.

Contents of the presentation Experimental Preparation of catalysts Wet impregnation Ion exchange Characterization X-ray diffraction Textural analysis Results and discussions Effect of Ni(2, 4, 6 wt%) loading on NaY Effect of Ni(2, 4, 6 wt%) and Pt (1 wt%) loading on NaY Effect of catalyst amount Effect of Temperature Glycerol hydrogenolysis over Ni and Pt-NaY Effect of Ca(OH)2 Conclusions

Experimental

Catalyst Preparation Catalysts prepared by wet impregnation method 2 wt%Ni/NaY 4 wt%Ni/NaY 6 wt%Ni/NaY Catalysts prepared by ion exchange method 8 wt%Ni/NaY 1 wt%Pt/NaY

Catalyst Preparation 1wt% of Pt2+(0.025M Pt(NH3)4Cl2+1.98g NaY Zeolite+25 ml water Refluxed at 80 °C/12h. Filtered and washed with water Dried at 110 °C/12 h Calcined at 400 °C / 4h 2, 4, 6 % Ni from Ni(NO)3.6H2O Dried at 110 °C/12 h Calcined at 400 °C / 4h Reduced at 400 °C with H2 Flow/ 3h Ni(2, 4, 6 wt%)- Pt(1 wt%)/NaY Zeolite Catalyst

Catalyst Preparation ( Ion Exchange) 8 wt% of Ni2+(0.05M of Ni(NO)3.6H2O) + 5g NaY Zeolite+100 ml water Refluxed at 80°C/ 12h. Filtered and washed with water Dried at 110 °C/12 h Calcined at 400 °C / 4h Reduced at 400 °C with H2 Flow/ 3h 8 wt%Ni/NaY Zeolite Catalyst

X-ray diffraction patterns of NaY and Ni-NaY Characterization X-ray diffraction patterns of NaY and Ni-NaY

X-ray diffraction patterns of NaY and Ni-Pt-NaY Characterization X-ray diffraction patterns of NaY and Ni-Pt-NaY

Surface areas of samples Characterization Sample BET Surface area (m2/g) NaY 548 6%Ni1%Pt/NaY 502 6%Ni/NaY 536 2%Ni1%Pt/NaY 482 2%Ni/NaY Surface areas of samples

Analytical procedures Products analysed by GC and Sorbitol analysed by making Trimethylsilyl derivative Preparation of Trimethylsilyl Sorbitol Derivative 5 ml of 15wt% Sorbitol + 1.5 ml DMF(As internal Standard) TMS Mixture(1ml Hexamethyldisilazane + 0.1ml trifluoroacetic acid) 0.5 ml of Internal standard + 0.5 ml of TMS Mixture TMS derivative of sorbitol

Results and Discussions

Important Products from Sorbitol Hydrogenolysis

Effect of Ni loading on Ni-NaY catalysts Conditions: 15 % sorbitol in water; temperature: 220 °C; catalyst amount: 0.5g; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm.

Effect of Ni loading on Pt(1 wt%)-NaY Conditions: 15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; catalyst amount: 0.5g; stirring speed: 300 rpm.

Effect of catalyst amount # Catalyst [amount, g] Sorbitol conversion (%) Product selectivity (%) Glycerol Dihydric alcohols Monohydric alcoholsa Polyolsb Othersc 1,2-PD EG 1 6%Ni-NaY [0.2] 24 12 53 10 5 16 4 2 6%Ni-NaY [0.5] 66 14 62 7 - 3 6%Ni-NaY [1.0] 68 15 60 11 15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm; a: methanol and ethanol; b: Trihydric (except glycerol) and higher alcohols; c: light products (some unidentified).

Effect of Temperature Conditions: 15 % sorbitol in water; catalyst: 6%Ni/NaY; catalyst amount: 0.5g; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm.

Effect of catalyst preparation method # Catalyst [amount, g] Sorbitol conversion (%) Selectivity (%) Glycerol Dihydric alcohols Monohydric alcoholsa Polyolsb Othersc 1,2-PD EG 1 NaY [0.5] 15 17 8 4 41 29 2 8%Ni-NaY (IE) [0.5] 54 20 9 14 33 16 3 6%Ni-NaY [0.5] 66 62 7 10 - 15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm; a: methanol and ethanol; b: Trihydric (except glycerol) and higher alcohols; c: light products (some unidentified).

X-ray diffraction Powder XRD patterns of (a) NaY, (b) reduced 8 wt% Ni-NaY (ion-exchanged) and (c) reduced 6 wt% Ni-NaY (impregnated).

Temperature programmed reduction profile H2 consumption of a) 6 wt% Ni/NaY 1.018 mmol/g ; b) 8 wt% Ni/NaY 0.254 mmol/g . Note: baseline correction was done to calculate H2 consumption for ‘b’

Glycerol hydrogenolysis over Ni & Pt-NaY # Catalyst [amount, g] Glycerol conversion (%) Selectivity (%) 1,2-PD EG Methanol Ethanol Others 3 1%Pt-NaY [0.5] 1 - 100 2 6%Ni-NaY [0.5] 32 56 4 38 15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm

Effect of Ca(OH)2 NO Catalyst [amount, g] Sorbitol conversion (%) Selectivity (%) Glycerol Dihydric alchols Monohydric alcholsa Polyolsb Othersc 1,2-PD EG 1 6%Ni-NaY [0.5] 66 14 62 7 10 - 2 6%Ni-NaY [0.5] +Ca(OH)2 [0.5] 75 4 69 5 8 3 1%Pt-NaY [0.5] 43 6 24 1%Pt-NaY [0.5] + Ca(OH)2 [0.5] 60 70 11 Ca(OH)2­ [0.5] 9 23 45 18 15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm; a: methanol and ethanol; b: Trihydric (except glycerol) and higher alcohols; c: light products (some unidentified).

Conclusions

Conclusions The hydrogenolysis of an aqueous solution of sorbitol takes place in the presence of H2 over Pt and Ni loaded on NaY. 1,2-PD is the major product; over the Ni-NaY, while glycerol is the major product over the Pt-NaY.

Continued… The addition of Pt to the Ni catalysts does not influence their activity or selectivity significantly. Ca(OH)2 promotes the performance of both Ni and Pt catalysts without affecting product selectivity. The catalyst 6%Ni/NaY (with Ca(OH)2) exhibited high conversion (75%) and good selectivity towards 1,2-PD (69%) at 220 °C.

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