Synthesis And Properties Of Alkylphenol Polyoxyethylenne Ethers Oligomer Surfactant

Five intermediates for preparing long chain n-alkylphenol polyoxyethylene ethers gemini surfactants(Bis(NP)), N,N'-Bis(2-hydroxy-5-alkylphenylmethyl)piperazine, were synthesized from fatty acyl chloride, phenol, paraformaldehyde, anhydrous piperazine through Friedel-Crafts acylation, Huang Minlon reduction and Mannich reaction. The molecular structures of intermediates were charactered by NMR, FTIR and elemental analysis. According to this synthesis route of N,N-Bis(2-hydroxy-5-alkylphenylmethyl)piperazine, the N,N'-Bis(2-hydroxy-5-nonylphenylmethyl)-piperazine has also been synthesized by using isononylphenol (industrial product) and paraformaldehyde successfully. Some factors affecting the N,N'-Bis(2-hydroxy-5-nonylphenylmethyl)-piperazine yield such as reaction temperature, solvent dosages, reaction time, were discussed. It was showed that when n-alkylphenol, paraformaldehyde and anhydrous piperazine at a molar ratio of 2∶2∶1, and reacted with reflux for 4 h., the product N,N-Bis(2-hydroxy-5-alkylphenylmethyl)piperazine yield could be reach to 75.6%.A series of novel nonionic Gemini surfactants ( hydrophilic groups oxyethylene (EO) chain numbers m=4, 7, 10, 15, 20, 30) were synthesized from N,N'-Bis(2-hydroxy-5-nonylphenylmethyl)-piperazine 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 and steady-state fluorescence probe method, respectively. The experimental results showed that critical micelle concentration (cmc) of the Bis(NP) was 3-7 times smaller than that of nonylphenol polyoxyethylene (NP), which has exhibited predominant surface activity of the Bis(NP). The micelle aggregation numbers (N) were increased linearly with the increase of the Bis(NP) concentration in the range of 5～9 times of cmc; both of cmc values and N values of the Bis(NP) were decreased with increasing the oxyethylene (EO) unit amount. The cmc values of gemini isononylphenol polyethoxylate-15 (Bis(NP)-15) and isononylphenol polyethoxylate-15 (NP-15) were 0.033 mmol·L-1 and 0.107 mmol·L-1. Their surface tensions at cmc were 46.8 mN·m-1 and 41.2 mN·m-1. And their cloud points were 94℃and 96℃, respectively.