Kinetic modeling of gas phase sugar cracking to glycolaldehyde and other oxygenates

Sugars can be cracked in a fluidized bed of glass beads to glycolaldehyde and various other oxygenate products that are valuable molecules on their own or as platform molecules for conversion into other chemicals. In this work, cracking of sugars was investigated experimentally and a kinetic model was developed. The model is based on calculated reaction rate parameters for isomerization and retro-aldol reactions available in the literature. The set of parameters was expanded with empirical reaction rate parameters obtained from fitting the kinetic model to experiments feeding glycolaldehyde and 1,3-dihydroxyacetone. The kinetic model was validated against experiments of glucose, fructose, and xylose cracking in the temperature range 440−600 °C. The experimental total carbon balance varied with the type of sugar and operating temperature in the range 77−97 wt % C. The temperature optimum for glycolaldehyde production was generally captured well by the kinetic model; however, the yield was overpredicted by the model (5−15 wt % C) for all sugars.