Synthesis And Properties Of Alkylphenol Gemini Surfactant

Five intermediates for preparing long chain n-alkylphenol Gemini surfactants, bis-(2-hydroxy-5-n-alkylphenyl)-methanes, were synthesized from fatty acid, phenol, and paraformaldehyde through Friedel-Crafts acylation, esterification, Fries rearrangement, Huang Minlon reduction, and condensation, and their molecular structures were confirmed by NMR and FTIR. According to this synthesis route of bis-(2-hydroxy-5-n-alkylphenyl)- methane, the bis-(2-hydroxy-5-nonylphenyl)-methane has also been synthesized by using isononylphenol (industrial product) and paraformaldehyde successfully. It was showed that when n-alkylphenol and paraformaldehyde in molar ratio 2:1 reacted at 130℃for 4 hours, the product yield could be reached 60.1% and the alkylphenol conversion and selectivity of product were 63.1% and 95.3% respectively.A series of novel nonionic Gemini surfactants (m = 4, 7, 10, 15, 20, 30) were synthesized from bis-(2-hydroxy-5-alkylphenyl)-methanes and ethylene oxide. Critical micelle concentrations (CMC) and surface tensions of the monomer and dimer surfactant in aqueous solution were tested by Wilhelmy-Plate method. The CMC of Gemini isononylphenol polyethoxylate-10 (GNP-10) and isononylphenol polyethoxylate-10 (NP-10) were 0.0242 mmol·L-1 and 0.0775 mmol·L-1. Their surface tensions at CMC were 38.3 mN·m-1 and 40.2 mN·m-1. Their HLB values were both 13.6. And their cloud points were 60℃and 53℃, respectively. The result showed that this kind of Gemini surfactant exhibited much better surface activity. GNP-10 showed shear-thinning behavior, while Newtonian behavior was found on NP-10. The viscosity of GNP-10 was higher than NP-10 at the same shear-rate.