Synthesis And Properties Of Nonadecane Alkyl Aryl Sulfonates

By means of molecular designing, we synthesised the the odd carbon number alkyl aryl sulfonates which the carbon number of long alkyl chain was nineteen.Through acyl chloride and xylene according to Friedel-Crafts reaction, got the alkyl aryl ketone intermediate. The reaction of alkyl xylene ketone and Grignard agent got a series of alkyl aryl tertiary alcohol isomeric compound, alkyl aryl tertiary alcohol had a reaction of reducation respectively, then got the alkyl aryl sulfonic acid by using HSO₃Cl as sulfonate agent to make an sulfonation reaction. Finally we obtained the series of definite structure odd number of carbon alkyl aryl sulfonates by neutralization and purification. The structures of intermediates and final products were confirmed to be correct by IR, ¹H NMR, ¹³C NMR.By using drop-volume method, the surface tension of alkyl aryl sulfonates were measured at different temperatures as well as in the electrolyte solution and the relationship between surface tension and structure, temperature and electrolyte were also obtained. At a given temperature, with the aromatic ring moving to the center of the long alkyl chain, micelle formation became harder, the critical micelle concentration (cmc) increased and the surface tension at cmc (γ_cmc) decreased; And with the addition of electrolyte, the cmc and theγ_cmc all greatly decreased compared with the value in pure water. For one structure-determined alkyl aryl sulfonate, as the temperature rises, micelle formation became more difficult, the cmc increased and theγ_cmc decreased. These phenomena were explained from the view of molecular structure of surfactant and the mechanism of electrolyte. Through the measurement of thermodynamic parameters in the formation of micelle, it can be realized that the process of micellization was mainly driven by the entropy, and the changes of enthalpy (â–³H_m⁰)and entropy (â–³S_m⁰)kept good linear relation, the compensation temperature was 304±2K.By using spinning drop method, the n_min value of alkyl aryl sulfonates were measured under a certain condition, it showed that with the aromatic ring moving to the center of the long alkyl chain, the n_min value increased gradually and the selectivity for alkanes also increased. At the fixed surfactant concentration, the optimum salt concentration, optimum alcohol concentration were obtained by measuring the interfacial tension between sulfonate solution and decane .The dynamic interfacial tension relationships between alkyl aryl sulfonates and the crude oil of 6th plant of Daqing oilfield were measured. Then the impacts of the structure of the sulfonates, the concentration of strong base and weak base on the minimum dynamic interfacial tension (DIFT_min) and the equilibrium dynamic interfacial tension(DIFT_equ) were respectively discussed. The results showed that all the interfacial tension between three kinds of alkyl aryl sulfonates and the crude oil of 6th plant of Daqing oilfield could reach ultra-low interfacial tension (10^-3mN/m) in their own optimum base concentration. Furthermore, with the aromatic ring moving to the center of the long alkyl chain, it could reach DIFT_min and DIFT_equ with lower base concentration and less time.The foam properties of alkyl aryl sulfonates were studied by Ross-Miles method. The results showed that with the aromatic ring moving to the center of the long alkyl chain, the foaming property increased and foam stability decreased. With the concentration of alkyl aryl sulfonates increased, the foaming property increased firstly and then approached equilibrium, but the foam stability increased at first, then decreased and got to a balanced value at last. As the temperature rises, the foaming property increased and the foam stability decreased.The emulsification properties of alkyl aryl sulfonates were studied by the meaning of water separation. The results showed that with the aromatic ring moving to the center of the long alkyl chain, the emulsification properties increased .