Synthesis And Properties Of Acetal Cation Surfactants Containing Nitrogen Heterocyclic

Surfactants are widely used in industry, agriculture, textile, daily chemical, medicine and other fields as an important functional material. The annual worldwide demand for it is more than 15 million tons. However, like a double-edged sword, surfactants can not only bring a lot of convenience to people but also deeply endanger the environment we live in. Every year the amount of residual surfactants poured into rivers and lakes is not less than a few hundred tons to bring seriously pollution for the natural environment. Today, with the continuous improvement of living standards, the requirements of the quality of life are constantly improving. In terms of surfactant, people not only request good surface properties but also pay more attention to whether it is environmentally friendly. For these reasons, the study to designe and synthesize the cleavable surfactants is interested in the world.The main research contents:(1) Two kinds of single cationic surfactants containing pyridine or imidazole ring and a double cationic surfactant containing imidazole ring were separately synthesized, using aldehyde, epoxy bromopropane, pyridine, benzimidazole and 1,ωdibromide alkane as raw materials. By optimizing synthesis conditions, such as material ratio, amount of catalyst, solvent, reaction temperature and time, the optimum synthesis conditions of 2-ethylhexy-1-4- chloromethyl-1,3-dioxa cyclopentane (1a),1-[(2-hexyl-1,3-Dioxane-4) Methyl]-1 benzimidazole(3a) and the product 2a were selected. (2) The critical micelle concentration, Krafft point, emulsification, foaming and foam stability of synthesized surfactants were determined. The critical micelle concentration of surfactant 2 (a～c) and 3 (d～f) were increasing with the decreasing of hydrophobic chain. The critical micelleconcentration of 2c,3f (2.2x10-3mol/L,1.2×10-3 mol/L) were far less than traditional surfactant dodecyltrimethylammoniumbromide (1.5×10-2 mol/L) and sodium dodecyl sulfate (8.6x10-3Mol/L), so their surface activity was significantly stronger than traditional surfactants. The single cationic surfactant 2 (a～c) and 3 (d～f) can be dissolved in water very well at room temperature, but the water solubility of 4 (e～f) is poor. Results showed that 2 (a～c) and 3 (d～f) have well the emulsifying and foaming properties.