Carbon-Based Solid Acids for the Preparation of Renewable Jet-Fuel- and Diesel-Range Alkanes from 2-Methylfuran and Phenylacetaldehyde

Developing renewable liquid fuels from lignocellulosic biomass is an important strategy for reducing dependence on fossil resources. 2-Methylfuran (2-MF), which can be obtained from biomass-derived furfural, is a promising platform molecule for constructing higher-carbon fuel precursors through hydroxyalkylation/alkylation (HAA) with carbonyl compounds. In this work, waste polycarbonate was converted into a carbon-based solid acid catalyst through alcoholysis, polymerization, calcination, and sulfonation. The resulting catalyst, denoted BPA-G-180, was applied to the HAA reaction of 2-MF with phenylacetaldehyde. It possesses a high titratable acid-site density (2.43 mmol g–1) with sulfonic acid groups supported on a stable carbonaceous framework. Under the tested conditions (2-MF/phenylacetaldehyde molar ratio = 2:1, 0.10 g catalyst, 50 °C, and 1 h), BPA-G-180 afforded a phenylacetaldehyde conversion of 98.4% and a carbon yield of 94.4% for the target product 1A. The catalyst also showed good applicability to HAA reactions involving vanillin, cyclopentanone, and cyclohexanone. Furthermore, the HAA product 1A was subjected to hydrodeoxygenation (HDO) over Pd/H-ZSM-5 at 200 °C and 4 MPa H2 for 24 h, affording a total carbon yield of 92.8% for C9–C18 hydrocarbons, with C18 cycloparaffins as the major fraction. This work integrates waste-polycarbonate valorization with the catalytic upgrading of 2-MF and provides an efficient route toward fuel-range hydrocarbons.