Study On Synthesis And Property Of A Series Of Mono-isomeric P-xylene-alkyl Benzene Sodium Sulfonates

In this paper,fatty acid chloride,?-bromoalkane and p-xylene were used as raw materials from the point of view of molecular design.to synthesize seven isomers of the mixture of dimethyl 18 alkyl benzene sulfonate.According to the position of the alkyl chain in the benzene ring were named as p-S18-2,p-S18-3,p-S18-4,p-S18-5,p-S18-6,p-S18-8,p-S18-9.It was proved by the high resolution chromatography mass spectrometry and 1H NMR that the synthetic material was the target product.The surface tension of the synthesized product was measured under the condition of the temperature of 45?and the mineralization degree of 4000mg/L NaCl solution,andthrough the drawing to calculate the corresponding cmc,?max?Am and a series of parameter values.The relationship between the structure and surface properties of alkyl benzene sulfonates was discussed.The results show that as the degree of branching increases,The corresponding cmc concentration is increasing,The surface tension of cmc decreases gradually.The saturated adsorption capacity of the solution increases,However,the area occupied by the molecules on the surface of the solution decreases gradually.Under the same test conditions,the dynamic interfacial tension(DIFT)of the synthesized product was measured using a rotating drop surface tension meter.The change of the interfacial tension with time is explored;At the same time,the steady-state interfacial tension values of n-alkanes with different chain lengths were measured,and the minimum alkane number of the surfactant nmin was obtained.It was found that as the benzene ring moved toward the center of the alkyl chain,it showed a tendency to decrease first and then increase.The interfacial tension with dodecane was also determined when the alkyl benzene sulfonate concentration was 0.1 wt%,0.2 wt%,and 0.3 wt%.The IFT changes of alkyl benzene sulfonates were investigated,indicating that the IFT of alkyl benzene sulfonates was controlled by both interfacial concentration and structure.At the same time,all the experimental results and the rules are explained in detail.