(548m) The Valorization of Sprayed Lignins with Ozone
Advanced biorefineries will be designed with the capability to process a diverse array of feedstocks. In addition, products should be easy to isolate and meet quality standards. Lignin biomass, the most abundant source of renewable aromatics, is as varied as its many plant sources. Constructed of globular units, alkene linkers within lignin differ between plant type. Oxidative scission of these lignin alkenes can partially depolymerize the material to afford valuable aromatic aldehyde products such as vanillin and deconstructed lignin. Here we discuss the ozonation of acid-solubilized lignins in an ambient temperature and pressure continuous spray reactor. Reaction products include vanillin, and 4-hydroxybenzaldehyde (>4.5 wt. % lignin) with an absence of overoxidized acid byproducts. Scanning electron microscopy reveals spherical lignin structures with a diameter of 10 nm which correlate with ~100k Dalton polymer species detected with gel phase chromatography. Spectroscopy of samples before and after reaction indicate that ozonized lignins is effectively treated for downstream globule depolymerization. This versatile process does depend on the lignin feedstock, but may be used to treat both grass and hardwood lignins.