Catalytic Dehydration of Glycerol to Acrolein over a Catalyst of Pd/LaY Zeolite and Comparison with the Chemical Equilibrium

Abstract

Glycerol dehydration to acrolein was studied with three catalysts using zeolite-Y. This zeolite in its protonic form (HY), with La (LaY) and Pd with La (Pd/LaY), was characterized by X-ray diffraction (XRD), Fourier-transform-infrared spectroscopy (FTIR) with pyridine, BET, Scanning Electron Microscope (SEM)-Energy-Dispersive Spectroscopy X-ray (EDS) and the catalytic activity tests were carried out under H 2 atmosphere. It was found that La ions exchanged in the zeolite-Y resulted in the improvement of both glycerol conversion and yield to acrolein, also a relatively constant glycerol conversion was achieved up to three hours, due to the presence of Pd on the catalyst and H 2 in the feed. The comparison of the calculated and experimental yields obtained from the catalytic tests of the Pd/LaY catalyst indicates a greater activity for the reaction to acrolein than for the reaction to acetol. The calculated equilibrium yields of the dehydration reaction from glycerol to acrolein, acetol, ethanal, methanol, and water and the experimental yields of a Pd/LaY catalyst were compared. Thermodynamically, a complete conversion of glycerol can be achieved since the general system remains exothermic and promotes the path to acetol below 480 K. Above this temperature the system consumes energy and favors the production of acrolein, reaching its maximum concentration at 600 K.

Recent Development of Heterogeneous Catalysis in the Transesterification of Glycerol to Glycerol Carbonate

“…Catalysts 2019, 9, 581 2 of 23 direct oxidation [9][10][11], hydrogenolysis [12,13], dehydration [14], acetalization [15], transesterification [16][17][18][19], etc. Amongst these products, glycerol carbonate is considered to be the most valuable product [20][21][22][23][24][25].…”

Nanosheet MFI Zeolites for Gas Phase Glycerol Dehydration to Acrolein

“…With the depletion of petroleum resources and growing concerns about environmental issues, increasing attention has been paid to the utilization of renewable resources, such as plant biomass [1,2]. As a main co-product in biodiesel production, glycerol is an important renewable resource derived from biomass [3][4][5][6]. Despite many applications in cosmetics, pharmaceuticals, and the tobacco industry, after expensive purification processes, glycerol production surplus is still a big problem [7,8].…”

Hydrogenolysis of glycerol to 1,2‐propanediol in a continuous flow trickle bed reactor

“…These are estimated values calculated with Joback's method . Values for acrolein were taken from the report of Lewars and Liebman and values for Gly from Tapia et al Reactions were classified with attention to their value of Gibbs free energy, or equilibrium constant ( K eq ), as being completely irreversible ( K eq > 10, Δ G° r < –10 kJ mol ‐1 ), unfeasible ( K eq < 1/10, Δ G° r > 10 kJ mol ‐1 ) and reversible (1/10 < K eq < 10, –10 kJ mol ‐1 < Δ G° r < 10 kJ mol ‐1 ).…”