Impact of synthesis conditions on Mg-Al mixed oxides for sustainable jet fuel intermediate synthesis

Magnesium-aluminum composite oxides (MgAlO) have attracted considerable attention in the field of fine chemical synthesis due to their unique layered precursor structures, tunable acid-base properties, and excellent thermal stability, particularly in forming carbon-carbon bonds via aldol condensation reactions. However, traditional methods for preparing MgAlO are relatively complex, and their catalytic performance is highly sensitive to synthesis conditions, which limits research on structure-activity relationships and the rational design of efficient catalysts. In this work, a bubble-assisted co-precipitation method was used to synthesize a series of MgAlO catalysts with tunable pore structures and surface properties. The synthesis conditions such as the Mg/Al molar ratio, pH, aging temperature, aging time, and calcination temperature were systematically adjusted to regulate the catalytic activity of the MgAlO materials. The self-condensation of cyclohexanone was used as a model system to investigate the effects of different synthesis conditions on catalytic performance. The physicochemical properties of the catalysts were characterized using XRD, FT-IR, and SEM. The results indicate that synthesis conditions significantly affect the crystal structure, specific surface area, pore size distribution, as well as the final catalytic activity and product selectivity. An optimized catalyst, MgAlO-3, featuring abundant mesoporous structure and active sites, achieved a total conversion of 98.8%. This work not only provides new insights into the green synthesis and structural regulation of MgAlO catalysts but also establishes an efficient heterogeneous catalytic system for the directional conversion of biomass platform molecules into sustainable aviation fuel.