Study On The Relationship Between Structure And Performances Of Surfactant Derived From Castor Oil

Castor oil acid methyl ester molecules are rich of reactive groups, including double bond, ester groups and hydroxyl. Its ester and hydroxyl groups could be reacted with ethylene oxide (EO) to synthetize castor oil acid methyl ester ethoxylate (CAMEE). Castor oil acid methyl ester ethoxylate sulfonate (GAMES) could be obtained by the addition reaction of its double bond with sodium bisulfite. What’s more,sodium ricinate branched polyoxyethylene ether (CAMEC) was obtained by CAMEE hydrolyzing under the condition of strong alkali. A series of GAMES and CMAEC with different average ethylene oxide (EO) adduct number was synthesized and structure-activity relationship was studied in this paper. Specific content includes the following four parts.1. The synthesis and identifying of CAMES. Refined castor oil as starting material could be successfully converted to castor oil acid methyl ester by ester exchange, which then reacted with EO to synthesize a series of CAMEE with different average adduct number of EO. CAMES was gained by the reaction of CAMEE and sodium bisulfite. In the experiment,we studied the structure of CAMEE,and then optimized the synthesis technology of CAMES to get optimum reaction condition. CAMES was also purified by extraction. Finally the structural feature of CAMES was characterized by Fourier transform infrared (FT-IR) spectra and Nuclear magnetic resonance spectroscopy (1HNMR). And its molecular structure was confirmed.2. Performance study of CAMEE and CAMES. The surface properties and application properties of CAMEE and CAMES with different average adduct number of EO were studied. These results indicated that CAMES is a kind of novel sulfonate surfactant which shows low foaming, strong emulsifying capacity and good surface activity. And when average adduct number of EO is the same, γcmc of CAMES is lower than that of CAMEE and its wettability, foaming capacity, foam stability, detergency and alkali resistance are all enhanced.3. CAMEC is an isomerous AEC , EO units of CAMEC are situated at the branched chain of its hydrophobic chain. CAMEC with different average adduct number of EO of 2,4 and 6 had been synthesized. The molecular structures were identified and their chemical properties were also studied. Results show that CAMEC is a new non-foaming anionic surfactant and its cmc is lower but γcmc is higher. Meanwhile, its wetting ability decreases with the increase of average adduct number of EO in the branched chain.4. Taking CAMEC4 for example, we studied the aggregation behavior of CAMEC in aqueous solution. We can conclude that vesicles form spontaneously in CAMEC4 aqueous solutions with the increasing of concentration and size of the vesicles decreased with the increasing of the concentration, but the stability of vesicles became poor. The intermolecular hydrogen bond interaction of CAMEC4 molecules is the reason of vesicle formation.