Glycerol as a sustainable C3 platform: contribution of 'heterogeneous' catalysis

During the last decade, glycerol has gained a lot of attention because of the rapid development of the vegetable oil industry especially for the production of biodiesel, lubricants, solvents, among others. Glycerol is the main co-product of the oleochemistry and the growing demand on biodiesel is now creating a significant glut of the glycerol production. In this context, the catalytic conversion of glycerol to higher value added chemicals has become of growing interest.
The recent advances made in the field of heterogeneous catalysis now open very efficient ways to selectively convert glycerol to a wide range of C3-monomers such as acrolein, acrylic and glyceric acids, glycidol, allylic alcohol, acrylonitrile, 1,3-propanediol, propylene glycol, among others. These biomass-based routes offer now suitable alternatives for preparing a diverse array of chemicals with a high content of renewably sourced ingredients. As for propene-based processes, the conversion of glycerol to C3-monomer generally requires harsh conditions such as a high temperature and, in some cases, a high pressure. Moreover, due to the presence of three hydroxyl groups on glycerol, many secondary products can be formed under such reaction conditions. The control of the reaction selectivity determines the viability of these glycerol-based processes. The rapid development of the material chemistry gives now access to a diverse array of sophisticated heterogeneous catalysts which were found particularly efficient for the selective conversion of glycerol.
In this communication, we will present the contribution of heterogeneous catalysis for the conversion of glycerol and glycerin to C-3 chemicals. In particular, we will make a comparative between the existing C-3 propene platform with that of glycerol. Even if it is clear that glycerol will not replace propene in the industrial production of C3-chemicals, we will present successful examples where glycerol has been incorporated into propene-based units.