Dihydroxyacetone Production: From Glycerol Catalytic Oxidation with Commercial Catalysts to Chromatographic Separation

Abstract

A process for catalytic production of dihydroxyacetone through glycerol oxidation and dihydroxyacetone purification by chromatographic processes is herein presented. Glycerol oxidation over commercial Pt/AC and Pt–Bi/AC catalysts was performed on a batch reactor operating under base-free conditions, using water as a solvent and oxygen as the oxidant agent. The highest dihydroxyacetone yield obtained was 36%, using the Pt5%-Bi1.5%/AC catalyst, whereas the monometallic Pt/AC catalyst was selective to glyceric acid. It is herein reported for the first time dihydroxyacetone separation from unreacted glycerol and reaction byproducts (organic acids). Two commercial polystyrene-divinylbenzene ion-exchange resins were used as a stationary phase, one in the hydrogen form and the other in the calcium form, and water was used as the mobile phase. Adsorption equilibrium data for the species present in the reaction mixture were determined in both resins through single-component adsorption breakthrough experiments. A continuous chromatographic separation process was designed based on the simulated moving bed (SMB) technology and simulated using the gPROMS model builder software. A two SMB cascade was then considered, performing the pseudobinary mixture separation on the first SMB. The extract stream from the first SMB containing dihydroxyacetone and glycerol was fed to the second SMB, obtaining dihydroxyacetone with a purity of 97%. Considering the overall unit, a dihydroxyacetone productivity of 64 kgDHA (LAds day)−1 was obtained with an eluent consumption of 1218 LDes kgDHA–1.