Application of hydrophobic catalyst in formaldehyde–ethylene condensation reaction.

This article focuses on the synthesis and evaluation of hydrophobic p-toluene sulfonic acid (p-TSA) catalysts supported on aerogel (AGL) carriers for the formaldehyde–ethylene condensation reaction to produce 1,3-propanediol (1,3-PDO). The study demonstrates that catalysts using hydrophobic AGL supports exhibit higher selectivity for 1,3-dioxane (1,3-DX) and better retention of active sites compared to hydrophilic SiO2-supported catalysts, with the highest 1,3-PDO selectivity reaching 80.5% when acetic acid is used as the solvent. Characterization techniques including XRD, IR, water contact angle, thermogravimetric, and elemental analyses reveal that catalyst hydrophobicity and particle size significantly influence catalytic performance by limiting active site loss and suppressing side reactions. Optimal reaction conditions were identified as 7.5 MPa pressure, a molar ratio of ethylene to formaldehyde of 3.11, catalyst to formaldehyde mass ratio of 0.32, temperature of 110 °C, and reaction time of 1.5 hours. The findings suggest that hydrophobic p-TSA/AGL catalysts are promising for industrial applications in producing 1,3-PDO via a pollution-free formaldehyde–ethylene condensation process.