Oxidation Kinetics of Carbon Deposited on Cerium‐Doped FePO₄ during Dehydration of Glycerol to Acrolein

Abstract

A cerium‐doped FePO4 catalyst dehydrates glycerol to acrolein in the gas phase but carbon accumulation reduces the reaction rate with time. Reaction rates may be maintained for longer times by co‐feeding low concentrations of oxygen together with the glycerol, but the acrolein yield drops proportionally to the oxygen concentration. The catalyst is easily regenerated by air and the reaction rate is proportional to both the oxygen concentration and quantity of carbon. The carbonaceous deposits may be due to both glycerol and acrolein: when either is fed to the catalyst, the CO2/CO ratio is close to 1; during the regeneration step, the CO2/CO ratio is near 4. A kinetic model of first order in both oxygen concentration and adsorbed sites characterizes the transient data very well.

Fluidized bed hydrodynamic modeling of CO2 in syngas: Distorted RTD curves due to adsorption on FCC

“…Consequently, this phase is neglected in the new model. 25 We consider catalyst as a distinct phase-solid phase. The third phase is the catalyst surface in its pores on which gas species adsorb.…”

Influence of Reaction Parameters on the Catalytic Performance of Alkaline-Treated Zeolites in the Novel Synthesis of Pyridine Bases from Glycerol and Ammonia

“…Compared to those for the single-stage reactor mode, the optimized conditions for the two-stage reactor mode are somewhat different. First, the temperature for the first-stage reactor is lower than that for the second-stage reactor, and both the temperatures have fallen in the normal ranges for the dehydration of glycerol to acrolein (250−350 °C) 7,8,[10][11][12][13][14][15][16]28,29 and for the condensation of acrolein and ammonia to pyridine bases (400−450 °C) 23 reported in the literature. Therefore, the employment of relatively low temperature in the first-stage reactor favors the generation of acrolein from glycerol and that of high temperature in the second-stage reactor promotes the generation of pyridine bases from acrolein.…”

“…Biomass, as an efficient substitute for traditional fossil fuel resources (coal, oil, and natural gas), is cheap, abundant, renewable, and environmentally friendly, and its application in the production of useful chemicals is of extremely great interest. − A representative biomassed compound is glycerol, which is currently manufactured on a large scale as the byproduct of biodiesel process. In recent years, the output of glycerol has exceeded greatly its consumptive market capacity; in fact, the overstock of glycerol has also caused a bottleneck, greatly hindering the further development of the biodiesel industry. − Therefore, the efficient utilization of glycerol is receiving more and more attention from both academic and industrial researchers.…”

Gas‐Phase Hydrogenolysis of Glycerol Catalyzed by Cu/MOx Catalysts

“…Conversion of glycerol into valueadded chemicals, such as propanediol, acrolein, hydroxyacetone, and glyceric acid by hydrogenolysis, dehydration, oxidation, and fermentation processes, is of great importance in view of biomass utilization [1][2][3][4][5]. Conversion of glycerol into valueadded chemicals, such as propanediol, acrolein, hydroxyacetone, and glyceric acid by hydrogenolysis, dehydration, oxidation, and fermentation processes, is of great importance in view of biomass utilization [1][2][3][4][5].…”

“…The rapid expansion of the biodiesel market has caused an oversupply of glycerol. Conversion of glycerol into valueadded chemicals, such as propanediol, acrolein, hydroxyacetone, and glyceric acid by hydrogenolysis, dehydration, oxidation, and fermentation processes, is of great importance in view of biomass utilization [1][2][3][4][5]. Among these processes, catalytic hydrogenolysis of glycerol provides a facile route for the production of propanediols, which are conventionally produced from propylene or ethylene via processes involving selective oxidation or chlorohydrin and subsequent hydration at considerable cost [6,7].…”