The current global struggles are largely focused on sourcing alternate fuels that can be reliably produced, easily distributed and environmentally benign. The solution is to adopt sustainably produced chemicals and fuels in a rapid and widespread manner.
Glycerol, a low value waste product accounts for 10% of the total products from the transesterification process to produce biodiesel.^1-2 This glycerol is heavily contaminated, therefore it is considered a waste of resources to purify and utilize this glycerol because of its low value and abundance.
Glycerol has the potential to be a versatile platform as it has applications in the food, pharmaceutical and cosmetic industries as well as it can be catalytically upgraded to form countless valuable drop-in chemicals. Propanediols production via hydrogenolysis of glycerol are of specific interest since they are traditionally obtained via fermentation processes. ³Glycerol can also produce hydrogen, thermocatalytically (via aqueous phase reforming, APR) and photocatalytically, leading to the formation of renewable hydrogen, as well as act as a hydrogen donor in catalytic transfer hydrogenation reactions.^2-4
This study evaluated the use of heterogeneous catalysts that were loaded at 1 wt% or less to self-upgrade glycerol to propanediols without external hydrogen present in the system. The employment of glycerol as a green hydrogen donor in the upgrade of another platform molecule, levulinic acid, to a fuel was done to evaluate its performance and suitability as a hydrogen donor.
Finally, the specific mode of hydrogen transfer (as hydrogen gas vs. hydride transfer) was probed using a combination of gas analysis and data comparisons and calculations to give insight into the mechanism of hydrogenation using glycerol as a hydrogen source.

Michael Forde

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