Selective Synthesis of Bio-based Benzaldehyde Using Magnetic CoFe₂O₄@Biochar(HTR) Catalyst^†

Developing green and efficient methods to acquire lignocellulose-based chemicals with high added value is beneficial for facilitating green chemistry and sustainable development. The goal of this study is to demonstrate that bio-based benzaldehyde, a noteworthy high-value chemical, is able to be directionally prepared from lignocellulosic biomass. This new controllable transformation was materialized by uniting catalytic-pyrolysis of lignocellulose to toluene intermediate and catalytic oxidation of toluene intermediate to bio-based benzaldehyde. This work also developed a highly active magnetic catalyst (CoFe₂O₄@Biochar(HTR)), achieving 77.1% benzaldehyde selectivity and 46.7% benzaldehyde yield using this catalyst. It was found that introducing the biochar carrier into the cobalt iron composite metal oxide catalyst enhanced hydroxyl radical formation and bio-based benzaldehyde synthesis. Based on catalyst characterizations and hydroxyl radical analysis, potential reaction mechanism for bio-based benzaldehyde synthesis was proposed. This strategy may provide a beneficial pathway for developing high-value bio-based chemical (benzaldehyde) using renewable lignocellulosic biomass.