On the role of Zr to facilitate the synthesis of diesel and jet fuel range intermediates from biomass-derived carbonyl compounds over aluminum phosphate

Heterogeneous zeolite/zeotype catalysts are attractive for converting renewable biomass-derived chemicals into transportation fuels by aldol condensation reactions, which provide a simple strategy to improve carbon numbers. Herein, Zr-doped aluminum phosphate (ZrAPO-5) were applied for efficient syntheses of diesel and jet fuel range C₁₁, C₁₂ and C₁₆ intermediates from biomass-derived furfural (FF) and cyclohexanone (CH). Incorporation of Zr in the APO-5 framework facilitated the adsorption of the C=O groups of FF and CH and created more and stronger acid and base sites, which co-catalyzed the aldol condensation and facilitated the product yields. ZrAPO-5 (Zr/Al = 0.20) yielded up to 79.3% single aldol condensation product C₁₁ or 80.7% double aldol condensation product C₁₆ in the cross-aldol condensation of FF and CH under appropriate reaction conditions, and also realized 83.3% C₁₂ yield in the self-aldol condensation of CH. In addition, the catalytic system displayed good to excellent yields of other value-added chemicals in aldol condensations of alternative carbonyl compounds.