| With the fast development of society and economy and the increasing deterioration of environment, it is urgent to research and develop the high efficient and environment-friendly surfactants. Gemini surfactants are honored as "nouveau surfactant",because of its superior performance of physics and chemistry, and the value of commercial development. This dissertation studies on the synthesis and properties of a serious of carboxylated bis-lauryl-polyoxyethene (n) maleate Gemini surfactants.The bis-easters (intermediate) were prepared by a series of lauryl-alcohol polyoxy- ethylene (n) ethers and maleic anhydride as the main reactants; and then react with fumaric acid to form carboxylated bis-laurylpolyoxyethene(n) maleate (end products). The synthetic condition of intermediate reaction was investigated by single factor analysis method in the course of the type and amount of catalyst, reactant molar ratio and reaction temperature. The optimum synthetic conditions were identified as follows: LEn : MAH=2.0:1.0; LE3,LE5: 0.1030mmol, reaction temperature 200℃; LE7,LE9: 0.1545mmol, reaction temperature 210℃. The final esterification ratios were 95.47%, 91.23%, 90.75%, 88.95%. The structures of these compounds were confirmed through IR and 1H NMR.The surface tension was determined by the Du.Nouy ring method. It was found that the critical micelle concentration(CMC) and the corresponding surface tension at such concentration(γCMC) were determined from theirγ-lgc curves, which were 34.17mN·m-1,33.26mN·m-1, 31.03mN·m-1, 29.98mN·m-1, CMC were 1.46mmol·L-1, 1.35 mmol·L-1, 1.26 mmol·L-1, 1.12 mmol·L-1. With the polyoxyethylene chain growth above, the CMC decreased and the surface tension (γCMC) also decreased.The surfactants also showed good properties of wetting, foaming, emulsification and decontamination. The results of wetting times were 8.56s, 16.32s, 14.21s, 13.67s; The foaming property tested by airflow method, Rv were 0.75, 0.65, 0.56, 0.47, and the t1/2 were 82min, 96min, 105min, 121min; emulsification times by mixed water and soybean oil were 14.08min, 15.81min, 17.69min, 18.46min, and the times by mixed water and hexane were 0.71min, 0.95min, 1.20min, 1.48min; decontamination ratio were 99.96%, 101.73%, 100.94%, 101.06%. The average particle size of TiO2 dispersion: 242.6nm, 228nm, 243.5nm, 256.6nm; the average Zeta potential: -79.37 mV, -75.02 mV, -71.68 mV, -63.67 mV.The test results show that the cleaning ability of the surfactants was better than the standard detergents. The detergency ratios were 51.8%, 49.8%, 51.3%, and 50.1%. Of Disperse Red 60 dispersion average particle size: 307.9nm, 322nm, 303.3nm, 311.5nm, the average Zeta potential: -107.6mV, -101.1mV, -72.16mV, -89.59mV; of Disperse Yellow 54 dispersion average particle size: 242.6nm, 228nm, 243.5nm, 256.6nm, the average Zeta potential: -79.37mV, -75.02mV, -71.68mV, -63.67mV. Looking over the results, it was found that Gemini surfactants dispersed Disperse Red FG very well, but not dispersion of Disperse Yellow E-3G changed inconspicuously.
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