Converting polyisoprene rubbers into bio-jet fuels via a cascade hydropyrolysis and vapor-phase hydrogenation process

Producing alternative drop-in bio-jet fuels from biomass provides a promising approach to achieve carbon neutrality. To upcycle biomass-based polyisoprene rubbers into jet-fuel range C10 cycloalkane, we proposed a cascade hydropyrolysis and vapor-phase hydrogenation process in a flow-through two-stage pressurized fixed -bed reactor. The hydropyrolysis temperature in the first stage is of vital importance for the formation of pri-mary limonene intermediate in the non-catalytic degradation of polyisoprene rubbers, and a reaction tempera-ture of 460 degrees C maximized limonene yield to 588.6 mg/g for natural rubber and 546.2 mg/g for Eucommia rubber. Over a Pt/C catalyst loaded in the second stage, the limonene intermediate produced from the first-stage reactor can be completely hydrogenated, giving a 642.7 mg/g yield of jet-fuel range C10 cycloalkane with 83.6% selectivity. The depolymerization mechanism of polyisoprene rubbers was thoroughly studied, and a competitive reaction between limonene hydrogenation and limonene dehydrogenation was observed. This is the first report on producing C10 cycloalkane from natural rubbers via a cascade hydropyrolysis and hydrogenation process, providing a promising strategy to upcycle polyisoprene rubbers into bio-jet fuels.

Automated summary

By using a cascade hydropyrolysis and hydrogenation process, polyisoprene rubbers can be upgraded to C10 cycloalkane for jet fuel, providing a promising strategy for bio-jet fuel production. The production of jet-fuel range C10 cycloalkane from natural rubbers via this process marks a significant advancement in biofuel technology.