Gas-Phase Fructose Conversion to Furfural in a Microfluidized Bed Reactor

Specialty chemicals from sugars are destined to displace fermentation to alcohols due to their superior economic value and atom efficiency. Compared to bioethanol, retention of oxygen functional groups increases by 2−5 times the market value of specialty chemicals like furfural, 2,5-furan dicarboxylic acid, 2,5-dimethyl furan, and γ-valerolactone. For the first time, we report a gas-phase process that converts C-6 monosaccharides to furfural in a microfluidized bed reactor. A spray nozzle inserted directly into the catalytic bed atomizes a fructose−water solution to micron-sized droplets; water evaporates, and WO3/TiO2 converts fructose to furfural. Furfural yield reached 22% after 3 h time-on-stream with 15% diformyl furan as coproduct. Acetic acid yield was mostly below 10% but was as high as 27%. During the initial tests, coke and catalyst agglomerates blocked the sparger tip, and run time varied between 1 and 3 h. Insulating the nozzle leading into the bed reduced the injector wall temperature and improved reactor operability; the 15 mm i.d. reactor ran continuously for 19 h after this modification.