(511f) Reactive Adsorption for the Selective Production of Furans From Carbohydrates
5-hydroxymethylfurfural (HMF) can be produced from the acid-catalyzed dehydration of fructose but its yield is limited due to subsequent HMF degradation to side products. We propose a reactive adsorption process to improve HMF yield1 by selectively removing it from the aqueous solvent as it is formed using an HCl catalyst in aqueous solution. Experimental isotherms of fructose, HMF, formic acid, and levulinic acid are obtained at relevant temperatures between 25-150ºC. Ideal adsorbed solution theory is used to approximate the adsorption of mixtures observed in the fructose dehydration reactor, based on separate experimental single-component isotherms. Reaction kinetics for fructose dehydration are specified using a recently-developed model based on experimental data under similar conditions. Both reaction and adsorption models are combined in a single unit to estimate the enhancement in HMF production that may be expected in such a process.
Experiments verified that reactive adsorption can enhance the HMF yield from fructose dehydration. The adsorbent can significantly improve HMF yield (from ~24% in a single-phase reactor to ~37% in a reactive adsorber at 100 ºC). The improvement is more pronounced at lower temperatures. Under certain conditions both reactive adsorption and the commonly used reactive extraction2 can result in a similar improvement in HMF yield. HMF recovery from the solid adsorbent can be achieved through adsorbent and solvent selection. This novel approach to the selective production of a reactive intermediate can be extended to other processes where the desired product is an intermediate in a reaction cascade.
(1) Swift, T. D.; Bagia, C.; Nikolakis, V.; Vlachos, D. G.; Peklaris, G.; Dornath, P.; Fan, W. AIChE J. 2013, In press.
(2) Roman-Leshkov, Y.; Chheda, J. N.; Dumesic, J. A. Science 2006, 312, 1933.