Production of precursors for sustainable aviation fuels through furfural/ cyclopentanone aldol condensation boosted by TiO2-loaded dendritic ZSM-5 catalysts

This study reports the catalytic performance of dendritic ZSM-5 (d-ZSM-5) catalysts in the aldol condensation ofcyclopentanone (CPO) and furfural (FFL), two biomass-derived molecules used to produce sustainable aviationfuel precursors. The dendritic architecture of ZSM-5 provides it with enhanced accessibility and textural features,including a large external surface area, high pore volume, and interconnected porosity. These are key parametersin the CPO/FFL aldol condensation due to the large molecular size of the products (FC and F2C) regarding theMFI micropore dimensions. In this way, and compared with a reference nanocrystalline ZSM-5 sample, thedendritic zeolite exhibited quite superior conversion and better selectivity towards the targeted condensationproducts across a wide range of CPO/FFL molar ratios (1/2 to 10/1). Likewise, the rational modification ofdendritic ZSM-5 with TiO2 is explored for the first time, showing how this strategy significantly enhances thecatalytic activity by providing an optimal balance of Brønsted and Lewis acidity and achieving a high dispersionof this metal oxide. Thus, the best catalyst (5 wt% TiO2/d-ZSM-5) reaches 93 % FFL conversion and 92 %selectivity to FC + F2C. These findings highlight TiO2-modified dendritic zeolites as promising, reusable catalystsfor upgrading biomass platform molecules into advanced aviation biofuel precursors.本研究报道了树枝状ZSM-5（d-ZSM-5）催化剂在环戊酮（cyclopentanone, CPO）与糠醛（furfural, FFL）的羟醛缩合反应中的催化性能，这两种生物质衍生分子均可用于制备可持续航空燃料前驱体。ZSM-5的树枝状结构赋予其优异的可接触性与织构特性，包括超大的外表面积、高孔体积以及相互连通的孔隙结构。由于产物（FC和F2C）的分子尺寸远大于MFI微孔的孔径，上述参数在CPO/FFL羟醛缩合反应中属于关键影响因素。与参比纳米晶ZSM-5样品相比，该树枝状沸石在宽泛的CPO/FFL摩尔比范围（1/2至10/1）内均展现出更优异的转化率与对目标缩合产物的选择性。本研究首次探索了采用TiO₂对树枝状ZSM-5进行理性改性的策略，结果表明该策略可通过调控布朗斯特（Brønsted）酸与路易斯（Lewis）酸的最优平衡，实现该金属氧化物的高分散性，从而显著提升催化活性。其中最优催化剂（5 wt% TiO₂/d-ZSM-5）的糠醛转化率可达93%，对FC+F2C的选择性为92%。上述研究结果凸显了TiO₂改性树枝状沸石作为极具潜力的可重复使用催化剂，可将生物质平台分子升级为先进航空生物燃料前驱体。