Chemical conversion of biomass to value-added products provides a sustainable alternative to the current chemical industry that is predominantly dependent on fossil fuels.N-heterocycles, including pyrroles, pyridines and indoles etc., are most abundant and important classes of heterocycles in nature and widely applied as pharmaceuticals, agrochemicals, dyes, and other functional materials. However, all starting compounds for the synthesis of N-heterocycles currently are derived from crude oil through complex multistep-processes and sometimes result in environmental problems. Catalytic fast pyrolysis is a promising technology to directly convert biomass and bio-derived chemicals to green aromatics over the zeolite catalysts.
Here, we develop a new sustainable technique to thermo-catalytically convert biomass with ammonia to a range of N-heterocycles including pyrroles, pyridines and indoles, from various kind of biomass such as cellulose, lignocellulose, sugars, starch, chitosan and so on by introducing ammonia as both active nitrogen source and carrier gas over HZSM-5 zeolite catalysts. The product distribution can be simply tuned to pyrroles, pyridines or indoles by changing the reaction units and conditions. We also outline the chemistry for the conversion of biomass into heterocycle molecules by the addition of ammonia into pyrolysis reactors demonstrating how industrial chemicals could be produced from renewable biomass resources. According to the pathway investigation, by reacting with ammonia, pyrroles were produced from the biomass pyrolytic intermediates, furans; pyridines were produced from the light oxygenated hydrocarbons such as aldyhydes and ketones; indoles converted from pyrroles. Meanwhile, N-containing biochar can be obtained as a valuable by-product. All desired reactions occur in one single-step reactor within seconds. The process can utilize traditional petrochemical industry equipment including fluidized bed reactors, distillation columns, and dryers.
See more of this Group/Topical: Sustainable Engineering Forum