| The hydroxyl sulfo betaine type surfactant is a kind of betaine type zwitterionics surfactant with unique within salt structure. It has excellent abilities of temperature and salt resistance, and eminent distribution performance as well. It also shows admirable interfacial activity in wide range of pH So it has a broad application prospect in the field of tertiary oil recovery as surfactant used in oil field.A series of hydroxysulfobetaine surfactants were obtained through synthesizing intermadiates, with epoxy chloropropane, sodium hydrogen sulfite, fatty alcohols, dimethylamine, et al as raw materials. N-(3-alkoxy-2-hydroxyl) propyl-N,N-dimethyl ammonium-(2-hydroxyl) propyl sodium sulfonate was their name, abbreviated CnSZ(n=8,10,12,14,16) according to hydrophobic carbon chain from C8 to C16. First, the ratio of materials in the synthesis of 3-chloro-2 hydroxy propyl sulfonic acid sodium was optimized and the optimum reaction temperature in the synthesis of glycidyl ether was determined by the way of single factor. Then, the conditions for quaternization were studied through orthogonal experiments, and the optimum process conditions were identified. Finally, the intermediate products and the surfactant were characterized by FTIR spectrum,1HNMR spectrum. The results indicated that the products were the desired products.The Krafft points, surface properties, and hard water stability were researched. It was found that Krafft points of all the novel surfactants were less than zero, exhibiting good water solubility. With the increase of the carbon chain length from C8 to C16, the values of CMC and ?cmc were gradually decreased from 9.1×10-4mol/L to 1.5×10-4mol/L and 36.4mN/m to 30.9mN/m, respectively. While the value of ycmc increased slightly when the carbon chain was C16.The values of CMC and ?cmc were all less than traditional cationic and anionic surfactant, namely N,N,N-trimethyl-1-dodecanaminium bromide and 1-dodecane sulfonic acid sodium salt, showed higher surface activity. At the same time, the results of solving other surface active parameters (pC20), ?max, Amin) stated that these surfactants had strong adsorption on gas-liquid interface and high efficiency in reducing surface tension. Surface active properties of these compounds increased with the increasing length of the carbon chain. The average stability classifications in hard water were all in grade 4, displaying excellent hard water resistance. In addition, using Warning-Blender method to test the foam properties of these surfactants, and determine the optimal concentration of foaming. The foaming volume and foam half-life were increased as the length of the carbon chain increasing initially and decreased afterwards, and C14SZ was superior in foam properties to the other four. Besides, emulsifiability was measured by means of recording the time of separating water in emulsion system, it concluded that the best concentration of emulsifying was decreased and the emulsion become more stable owing to the increase of the carbon chain length.Oil-water interface performance of desired products were studied, the results demonstrated that the interfacial tension at the water/oil interface of C12SZ and C14SZ reached 10-3mN/m that met the requirements of surfactant used for oil recovery, and the salt and temperature resistance of them were all better than that of dodecyl propyl sulfo betaine surfactant. Selecting C12SZ and C14SZ to mix with nonionic surfactants, anion surfactants, anion-nonionic surfactants, and the complex system that interfacial tension reached 10-3mN/m was chose for salt and temperature resistance studies. Finally, the C12SZ/AESO (fatty alcohol polyoxyethylene ether sulfonates) was screened out as the best complex system.The effects of temperature, salinity, and pH on the oil-water interface performance of C12SZ/AESO (I 4)were investigated. The results showed that the interfacial tension kept in 10-3mN/m and met the requirements of surfactant used for oil recovery in these conditions that the temperature was between 35? and 85?, the concentration of Na+ was less than 40000mg/L and the concentration of Ca2+ was less than 5000mg/L, and the value of pH was from 2 to 12, respective. In conclusion, the C12SZ/AESO complex system showed notable salt resistance, significant temperature resistance, stability in wide range of pH. The system of C12SZ/AESO could remain stable, had ultra-low oil-water interfacial tension, used in wide range of pH owing to the unique within salt structure and hydroxyl in C12SZ and polyoxyethylene in AESO. |
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