The Synthesis Of Quaternary Ammonium Salt-type Tetrameric Surfactants And Their Properties

Compared with the traditional single-chain surfactants,oligomeric surfactants have higher surface activity and lower critical micelle concentration because of their special molecular structure,and broader application prospects.So far,there are many researches on the quaternary ammonium salt type Gemini(dimerization)surfactants,but there are few reports on surfactants of trimeric,tetraameric and even higher degree of polymerization.Based on the previous experience in synthesizing Gemini surfactants and the structural characteristics of Gemini surfactants,we used pentaerythritol as the core to synthesize dendritic quaternary ammonium salt type tetraameric surfactants firstly(4Cntetra Q,n=12,14,16),and study its physicochemical properties and application performance.The main contents and research results are as follows:1.A series of quaternary ammonium tetraamer surfactants were synthesized from pentaerythritol,epichlorohydrin and tertiary amine.Purity was determined by the melting point,and its molecular structure was characterized by FT-IR and1 H NMR,and the analytical results were consistent with the theoretical structure of the molecule;2.The solubility and krafft points of 4Cntetra Q were determined.The results show that 4C12 tetra Q and 4C14 tetra Q have better solubility and lower krraft points than 4C16 tetra Q,which indicates that they have a wider range of applications;3.The surface tension and critical micelle concentration(cmc)of 4C12 tetra Q,4C14 tetra Q and 4C16 tetra Q surfactants were measured using a QBZY-2 automatic surface tensiometer by platinum plate method at 25°C,where the values of cmc were 0.37 mmol/L,0.046 mmol/L and 0.00547 mmol/Lrespectively,which are higher than that of the single-chain surfactant DTAB(15.7 mmol/L);4.The emulsifying effect of 4Cntetra Q for liquid paraffin was determined by the waterdivision time method.The results showed that 4Cntetra Q has stronger emulsifying power than that of the traditional single-chain surfactant(DTAB).In addition,4C16 tetra Q have the best emulsification performance;5.The foamperformance of 4Cntetra Q were measured by Ross-miles method,and compared with the emulsifying properties of the single-chain surfactant DTAB,the foam performance of 4Cntetra Q was better than that of DTAB;6.The conductivity of 4Cntetra Q was measured at different temperatures,and the degree of reverse ion binding(?)and the critical micelle concentration(cmc)were obtained from the relation curves of conductivity vs.concentration.The values of cmc measured at 25°C were corresponding with those by platinum plate method.The relationships between cmc and surfactant molecular structure and temperature were studied,the results showed that the values of cmc derease with the increment of the experimental temputatures and length of carbon chain from 12 to 16;the micellization behaviors of 4Cntetra Q in aqueous solution werealso investigated.The results show that the micellization of 4C12 tetra Q,4C14 tetra Q and 4C16 tetra Q surfactants in aqueous solution was spontaneous,and the values of ?Go mic gradually decreased with the increase of the length of hydrophobic alkyl chain;7.At room temperature,the values of cmc and micellar aggregation number of the quaternary ammonium salt tetraameric surfactant were determined by steady-state fluorescence probe method,where the cmc value was consistent with that determined by the platinum plate method and the conductivity method;8.The extinction dilution method was used to study the bactericidal performance of 4C12 tetra Q againstthe sulfate-reducing bacteria(SRB)in oil field sewage.The results show that when the concentration was 15 mg/L,the bactericidal ration of 4C12 tetra Q is much higher than traditional fungicides(1227),up to 95.1%;9.The corrosion inhibition performance of 4C12 tetra Q was investigated by weight-loss method and electrochemical method.The results showed thpat the adsorption of 4C12 tetra Q on A3 carbon steel surface conforms to the Langmuir adsorption model,and when the concentration of 4C12 tetra Q was 45mg/L,the inhibition efficiency reached 95.8%.Scanning electron microscope(SEM)was used to prove the high corrosion inhibition performance of 4C12 tetra Q microscopically;...