The SnCl4-bentonite-7 catalyst, loaded with SnCl4 on bentonite, was prepared for the catalytic aldol condensation reaction between 1,3,5-trioxane (TOX) and diethylene glycol butyl ether (DEGB) to synthesize diethylene glycol butyl ether formaldehyde (DBF).The catalyst"s structure and morphology were characterized by FTIR, SEM, and XRD. The effects of reaction temperature, the molar ratio of TOX to DEGB, and the percentage of cyclohexane as a hydrotrope (based on the total mass of TOX and DEGB) on the selectivity and yield of DBF were examined. DBF was used as a plasticizer for nitrile butadiene rubber (NBR), with its performance compared to the imported plasticizer TP-90B through mechanical tests and thermal aging experiments.The results show that the highest selectivity (98.2%) and yield (94.7%) of DBF were achieved at 110°C, with a TOX to DEGB molar ratio of 1:6.6, and a cyclohexane content of 30%, using 3% of the SnCl4-bentonite-7 catalyst. Compared to TP-90B, DBF/NBR demonstrated superior vulcanization characteristics, mechanical properties, and aging resistance. Specifically, the maximum torque of DBF/NBR (13.01 dN·m) was higher than that of TP-90B/NBR (12.85 dN·m), with shorter scorch time and optimum vulcanization time of 0.53 min and 1.42 min, respectively, compared to 0.55 min and 1.47 min for TP-90B/NBR. Additionally, DBF/NBR showed higher hardness, tensile stress at 100% elongation, elongation at break, tensile strength, and tear strength. During thermal aging tests, DBF/NBR exhibited significantly less variation in tensile and tear strength compared to TP-90B/NBR.