Synthesis of high-density bio-jet fuel by one-pot Mannich-Michael reaction and subsequent hydrodeoxygenation over alkali-treated zeolite catalysts

Cycloalkanes jet fuel with high-density derived from biomass are the ideal alternative to fossil fuel. The one-pot Mannich-Michael reaction of cyclopentanone and formaldehyde followed by hydrodeoxygenation (HDO) is a prospective route for the synthesis of cyclic high-density jet fuel. The synergistic interaction of pyrrolidine with acetic acid exhibited high catalytic activity in the one-pot Mannich-Michael reaction under mild conditions (50 celcius, 6 h). Additionally, solvents with appropriate polarity promote proton transfer to form Mannich bases, which are subsequently decomposed to produce 2-methylenecyclopentanone as the substrate for Michael addition. Thus, a high yield of condensed products (92.3%) with 93.3% conversion of cyclopentanone was obtained via an enamine catalytic pathway. The alkali-treated H beta 25-1 combined with Pd/C effectively catalyze the HDO of condensate products. The alkali-treated H beta 25-1 with larger mesoporous volume and sufficient acid sites lead to a high yield of dicyclopentylmethane (73.6%). The density and heating value of the HDO liquid products were 0.906 g/cm3 and 40.5 MJ/L, respectively. This work provided a novel route for high-density jet-fuel from lignocellulosic platform compounds.

Automated summary

Cycloalkanes jet fuel derived from biomass is the perfect alternative to fossil fuel. The Mannich-Michael reaction of cyclopentanone and formaldehyde followed by hydrodeoxygenation (HDO) is a promising method for producing high-density jet fuel. The combination of pyrrolidine and acetic acid showed high catalytic activity in the one-pot Mannich-Michael reaction under mild conditions. By using the enamine catalytic pathway, a high yield of condensed products and conversion of cyclopentanone was achieved. The alkali-treated H beta 25-1 catalyst combined with Pd/C effectively catalyzed the hydrodeoxygenation of the condensed products, resulting in a high yield of dicyclopentylmethane with desirable density and heating value. This work provides a new route for producing high-density jet fuel from lignocellulosic compounds.