Study On The Relationship Between Structure And Performances Of Surfactant With Two Functional Groups Derived From Oleic Acid

The oleic acid is a natural renewable material,in this thesis,the methyl oleate was derived from oleic acid through methyl esterication reaction,and then it was ethoxylated to obtain oleic acid methyl ester ethoxylate(OMEE).Ethoxylated methyl oleate sulfonate(OMEES)was obtained by sulfonation with sodium bisulfite.In addition,α-sulfo carboxylic disodium salt(SCDS)was synthesized via saponification reaction of fatty acid methyl ester sulfonate sodium(MES).Take OMEE,OMEES and SCDS which all contain double active functional groups as the research objects,the physicochemical properties such as surface tension(static/dynamic),contact angle,steady state fluorescence,etc.and the usage properties including wetting,emulsification,foaming and decontamination were measured.The relationship between the molecular structure and performance was explored on the base of these researches.The specific content of this paper includes the following four parts:1.Preparation and performances study of OMEE.The methyl oleate was got by the methyl esterification of oleic acid,and then it was directly reacted with ethylene oxide(EO)in the presence of the catalyst to obtain the OMEE.The chemical analysis method and infrared spectroscopy were used to identify the molecular structure of OMEE,and its performances were compared with the saturated fatty acid methyl ester ethoxylate(FMEE).The results show that the cmc and γcmc of OMEE are slightly higher than those of FMEE,and its foam and decontamination ability are weakened,but the wetting and emulsifying ability were enhanced compared with FMEE.2.Preparation and performances study of OMEES.OMEES was synthesized by sulfonation of OMEE with Na HSO3,and tert-butyl peroxybenzoate and ferric chloride are the catalyst and cocatalyst respectively.The structure of the target product was confirmed by chemical and physical analysis.Besides,the results show that the introduction of the sulfo group can improve the hydrophilicity of OMEE and decrease the γcmc,but the adsorption rate and the adsorption capacity at the gas/liquid interface are decreased.Wetting,emulsification,and decontamination capabilities of OMEES are deteriorated,however,the foaming ability is enhanced.3.Study on the acid and alkali resistance of OMEE and OMEES.The hydrolysis rates of OMEE,FMEE and OMEES were quantified and accurately measured by the extraction method and the liquid chromatography method.The results show that FMEE has the best acid and alkali resistance and OMEE has the worst,while OMEES hydrolyzed very fast in the strong alkaline condition(p H=13).It is apparent that the introduction of the sulfo group enhances the acid and alkali resistance of the OMEE effectively,from p H 2 to p H 11.4.Preparation and properties research of α-sulfo carboxylic disodium salt.It was producted by saponification of α-sulfo fatty acid methyl ester with excess sodium hydroxide.Through the comparison of the two surfactants’ activity parameters,the efficiency of SCDS in reducing the surface tension of the solution is lower than MES,but its ability is stronger than that of MES.In addition,due to the increase of the number of hydrophilic head,the Krafft point of SCDS increases significantly and the number of micelle aggregates increases.With the increase of temperature,the wetting performance of the disodium salt is greatly improved,and the emulsifying ability of the soybean oil is also superior to the MES.In particular,the SCDS exhibits very excellent foam capacity.