Abstract: Mannich base detergents with different structures were synthesized and their detergency properties for gasoline and diesel fuel were evaluated. The relationship between the molecular structure, thermal stability, solubilization and bond energy of Mannich base with detergency property was discussed. The results showed that Mono and Bis Mannich base had better detergencies, but Diamine had worse detergency. Increasing the number of nitrogen atom in Mannich base amines could not further improve its cleaning performance. The higher the thermal stability of Mannich base, the better the cleaning performance. When the thermal stability was equal, the stronger the solubility, the better the cleanliness. The carbon-nitrogen bond energy generated by secondary amine in Mannich base molecule was less than that generated by primary amine, and it is easy to break at high temperature, resulting in poor cleaning performance of mannich base.

Key words: Mannich base, fuel detergent, molecular structure, performance study