1. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols
DOI /cssc
Arundhathi RACHA
Department of Materials Engineering Science,
Graduate School of Engineering Science,
Toyonaka, Osaka University- Osaka , Japan

2. Renewable Chemicals: Dehydroxylation of Glycerol and Polyols
(Jeroen ten Dam and Ulf Hanefeld)
(ChemSusChem 2011,4, ; DOI /cssc )
Renewable chemicals from natural resources e.g, sugars, cellulose and hemicellulose in a sustainable way.
Dehydroxylation, a fundamentally different approach of defunctioanlize of hydroxyl groups to yield renewable chemicals.
Defunctionalizing of biomass vs. functionalizing of oil

3. Selective dehydroxylation of Biomass
Design of catalysts that can selectively remove some of the functionalities .
Selective conversion of polyols, i.e dehydration and hydrogenation.
Selective dehydroxylation of Biomass
Six approaches for deoxgenation
1. Dehydration of vicinal diols and hydrogenation of carbonyl groups
2. Dehydration of alcohols and hydrogenation of carbon–carbon double bonds
3. Condensation of alcohols and hydrogenolysis of the resulting cyclic ethers
4. Hydrogenolysis of ethers
5. Ketonization of carboxylic acids
6. Hydrogenation of carboxylic acids

4. Selective dehydroxylation of polyols
Acid-catalyzed E1 mechanism
Base-catalyzed E2 mechanism
Hydrogenolysis

5. Sequential elimination (dehydration) and hydrogenation process.
Endothermic (dehydration) versus exothermic (hydrogenation) –product selectivity.
Need for design the catalyst which directs the overall process to occur via one specific dehydration pathway.

6. Dehydration -Hydrogenation
Dehydration selectivity determining the value-added chemicals from glycerol
Bronsted acid assist in eliminating secondary hydroxyl group
Lewis acid assist in eliminating primary hydroxyl group

7. Dehydration of alcohols and hydrogenation of carbon–carbon double bonds
Condensation of alcohols and hydrogenolysis of the resulting cyclic ethers
The reaction sequence is not applicable to glycerol, since the condensation of alcohols in order to form cyclic ethers is limited to five-membered (or larger) ring systems.

8. Glycerol to 1,2-propanediol
Under alkaline conditions, 12PD is being formed via glyceraldehyde
Under acidic conditions, acetol is generally is the key intermediate

9. !,2-propanediol from Glycerol

10. Glycerol to 1,3-propanediol
Selective production of 13PD is more challenging than 12PD
Active catalyst for 12PD production, selective catalyst for 13PD production
The factors that are important to influence 13PD formation are slowly being unraveled

11. Effect of impregnated metals and solvent on WO3/ZrO2
support for 13-PD selectivity

12. Additives improving the conversion and selctivity towards 13PD
Protic solvent improves the reaction towards 13PD by facilitating proton transfer from solid acid to secondary alcohol by stabilizing a charged intermediate.
Additives improving the conversion and selctivity towards 13PD
Pt/WO3/ZrO2 facilitates the homolytic cleavage of hydrogen on platinum and
subsequent spillover

13. Fixed bed reactor Pt/WO3/ZrO2 (Quin et al.) Pt/WO3/TiO2 (Gong et al.)
Tungsten additive for the improving Gly Conv and Selc towards 13PD
Fixed bed reactor
Pt/WO3/ZrO2
70% Conv.; 46% Selec.
403 K
(Quin et al.)
Pt/WO3/TiO2
7.5% Conv.; 44% Selec.
(Gong et al.)
Pt/WO3/TiO2/SiO2
15% Conv.; 51% Selec.
(Gong et al.)
Cu-STA/SiO2
70% Conv.; 46% Selec.
(Huang et al.)

14. Rh/SiO2 (Furikado et al.) Rh-ReOx/SiO2 (Furikado et al.) Ir-ReOx/SiO2
Rhenium additive for the improving Gly Conv. and Selc. towards 13PD
Rh/SiO2
14.3% Conv.; 9.8% Selec.
(Furikado et al.)
Rh-ReOx/SiO2
79% Conv.; 14% Selec.
(Furikado et al.)
Ir-ReOx/SiO2
50% Conv.; 49% Selec.
(Furikado et al.)
Pt-Re/C
20% Conv.; 34% Selec.
(Daniel et al.)
Pt-Re/C
45% Conv.; 29% Selec.
(Tomishige et al.)

16. Glycerol to acrolein

17. Glycerol to Lactic acid

18. Glycerol to Acrylonitrile
Glycerol to Epichlorohydrin

19. Glycerol to Ethylene glycol
Longer Chain polyols

20. 5-Hydroxymethylfurfural (HMF formation form D-Glucose)

21. Conclusions
1. The smallest polyol Glycerol can be deoxygenated into a range of useful chemicals .
2. Major deoxygenation products from Glycerol are 12PD, 13PD and acrolein.
3. The catalyst for acrolein formation might be a good lead for new catalyst development for 13Pd, as both share the same intermediate.
4. The process can also be applied for long chain polyols for the production of important derivative like 5-HMF.
References:
Please refer to
Renewable chemicals: Dehydroxylation of Glycerol and Polyols
Jeroen ten Dam and Ulf Hanefeld
ChemSusChem 2011, 4, ; DOI: /cssc

22. Thank you !!