Hydrogenolysis of Sorbitol over Ni and Pt loaded on NaY

M.Banu4thAnnual Day

01.08.2010

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.

Introduction

CelluloseCellulose

glucoseglucose

SorbitolSorbitol

PG, EG Antifreeze

PG, EG Antifreeze

Glycerol Plastics

Glycerol Plastics

Lactic acidBiodegradable

plastics

Lactic acidBiodegradable

plastics

L-SorboseVitamins

L-SorboseVitamins

BioethanolBioethanol

• 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.

Continued...

ExperimentalPreparation of catalysts

Wet impregnation Ion exchange

CharacterizationX-ray diffractionTextural analysis

Results and discussions

Effect of Ni(2, 4, 6 wt%) loading on NaYEffect of Ni(2, 4, 6 wt%) and Pt (1 wt%) loading on NaYEffect of catalyst amountEffect of TemperatureGlycerol hydrogenolysis over Ni and Pt-NaYEffect of Ca(OH)2

Conclusions

Contents of the presentation

Experimental

Catalysts prepared by wet impregnation method

2 wt%Ni/NaY4 wt%Ni/NaY6 wt%Ni/NaY

Catalysts prepared by ion exchange method

8 wt%Ni/NaY1 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.

2, 4, 6 % Ni from Ni(NO)3.6H2O

Filtered and washed with water

Dried at 110 °C/12 h

Ni(2, 4, 6 wt%)- Pt(1 wt%)/NaY Zeolite Catalyst

Calcined at 400 °C / 4h

Dried at 110 °C/12 h

Catalyst Preparation

Calcined at 400 °C / 4h

Reduced at 400 °C with H2 Flow/

3h

8 wt% of Ni2+(0.05M of Ni(NO)3.6H2O)+

5g NaY Zeolite+100 ml water

Refluxed at 80°C/ 12h.

Reduced at 400 °C with H2

Flow/ 3h

Filtered and washed with water

Dried at 110 °C/12 h

8 wt%Ni/NaY Zeolite Catalyst

Catalyst Preparation ( Ion Exchange)

Calcined at 400 °C / 4h

X-ray diffraction patterns of NaY and Ni-NaY

Characterization

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

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 536

Surface areas of samples

Characterization

Analytical procedures

Products analysed by GC and Sorbitol analysed by making Trimethylsilyl derivative

5 ml of 15wt% Sorbitol + 1.5 ml DMF(As internal Standard)

TMS Mixture(1ml Hexamethyldisilazane + 0.1ml trifluoroacetic acid)

TMS derivative of sorbitol

0.5 ml of Internal standard + 0.5 ml of TMS Mixture

Preparation of Trimethylsilyl Sorbitol Derivative

Results and Discussions

OH

OH

OH

OH

OH

HOOH

OH

HO

HO

OH

OH

OH

OH

OH

OH

HOOH

EG

OH

Methanol

OH

Ethanol

CH4

Methane

H2

Sorbitol

Xylitol

Glycerol 1,2-PD

HO OH

1,3-PD

(I)

(II) (III)

,

,,

(IV) (V)

(VI)

HO

OH

OH

OH

Erythritol

,

Important Products from Sorbitol Hydrogenolysis

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 Ni-NaY catalysts

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.

#

Catalyst

[amount,

g]

Sorbitol

conversi

on (%)

Product selectivity (%)

Glycer

ol

Dihydric

alcohols Monohydr

ic

alcoholsa

Polyol

sb

Others

c

1,2-PD EG

16%Ni-NaY

[0.2]24 12 53 10 5 16 4

26%Ni-NaY

[0.5]66 14 62 7 7 10 -

36%Ni-NaY

[1.0]68 15 60 7 7 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 catalyst amount

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 Temperature

# Catalyst[amount, g]

Sorbitol conversion (%)

Selectivity (%)

Glycerol

Dihydric alcohols

Monohydric alcoholsa

Polyolsb

Othersc

1,2-PD

EG

1 NaY [0.5] 15 17 8 1 4 41 29

28%Ni-NaY (IE) [0.5]

54 8 20 9 14 33 16

36%Ni-NaY

[0.5]66 14 62 7 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).

Effect of catalyst preparation method

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’

# Catalyst[amount, g]

Glycerol conversion (%)

Selectivity (%)

1,2-PD EG Methanol Ethanol

Others

31%Pt-NaY

[0.5]1 - - 100 - -

26%Ni-NaY

[0.5] 32 1 1 56 4 38

15 % sorbitol in water; temperature: 220 °C; pressure: 60 bar; time: 6 h; stirring speed: 300 rpm

Glycerol hydrogenolysis over Ni & Pt-NaY

NO Catalyst[amount, g]

Sorbitol conversion (%)

Selectivity (%)

Glycerol

Dihydric alchols

Monohydric alcholsa

Polyolsb

Othersc

1,2-PD

EG

16%Ni-NaY

[0.5]66 14 62 7 7 10 -

2

6%Ni-NaY [0.5]

+Ca(OH)2 [0.5]

75 4 69 7 5 8 7

31%Pt-NaY

[0.5]43 62 6 3 24 1 4

4

1%Pt-NaY [0.5] +Ca(OH)2

[0.5]

60 70 6 3 11 2 8

5Ca(OH)2

[0.5]24 3 9 2 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).

Effect of Ca(OH)2

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.

OHOH

OH

OH

OH

HO

OH

OH

HO

OH

OH

H2

Sorbitol

Glycerol

1,2-PD

Ni-NaYH2

Pt-NaY

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.

Continued…