Synthesis And Properties Of Long Chain Fatty Alcohol Polyoxyethylene Ether Deirvatives

This thesis work focuses on long fatty alcohol polyoxyethylene ether propionate andsulfate, a sort of anionic-nonionic mixed surfactants with mildness, low toxicity and otherexcellent performances, which are widely used in various industries.Fatty alcohol polyoxyethylene ether propionate(symbolized as C₁₂AEnP, n=3,4,7,9;C₁₈AE₂P) was synthesized with fatty alcohol polyoxyethylene ether(C₁₂AEOnand C₁₈AEO₂)and methyl acrylate as raw materials. Optimum reaction conditions were explored byorthogonal experiment in order to maximize the conversion rate. The optimum reactionconditions were determined as following: molar ratio of methyl acrylate to fatty alcoholpolyoxyethylene ether was3:1; amount of catalyst was0.75%（based on the mass of fattyalcohol polyoxyethylene ether）; reaction time was₁₂ h; reaction temperature was80℃. Theconversion rate of fatty alcohol polyoxyethylene ether under the condition above was86.5%.Octadecanol polyoxyethylene ether sulfate (symbolized as C₁₈AES and C₁₈AESA) wassynthesized using C₁₈AEO₂and chlorosulfonic acid by sulfonation reaction. The reactionconditions were determined as following: molar ratio of C₁₈AEO₂to chlorosulfonic acid was1:1.1; reaction temperature was50℃; reaction time was eighty minutes; taget product wasneutralized with sodium hydroxide （triethanolamine） solution. The yields of C₁₈AES andC₁₈AESA were93.6%and90.2%respectively.The surface tension and counterion binding degree of target products at differenttemperatures and concentrations of NaCl were determined by drop volume method andelectric conductivity method. Subsequently we calculated the corresponding surface chemicalparameters: Γmax, Amin, C20and pC20. The results show that with the increase of temperature,γcmcand maximum surface adsorption capacity（Γmax） decrease and critical micelleconcentration（cmc） increases a little. Under certain concentration of sodium chloride andtemperature, γcmcand cmc increase with the increase of EO number. Under certaintemperature, γcmcincreases and cmc decreases with the increase of alkyl carbon chain length.Under certain temperature, γcmcand cmc gradually decrease with the increase of theconcentration of sodium chloride. The thermodynamic parameters of surface adsorption andmicellization of C₁₂AEnP at different temperatures were calculated. The results show that theprocesses of surface adsorption and micellization of this kind of surfactants are allspontaneous processes driven by entropy.The aggregation number and micropolarity of surfactants’ micelles were determined bysteady-state fluorescence probe method. The results show that the micelle aggregation numberincreases and micropolarity of micellar core becomes weak with increasing concentration offatty alcohol polyoxyethylene ether propionate. The properties of the final products were determined, including thermal stability, hydrophilicity and lipophilicity, foaming,emulsification, wetting and so on. The results show that the products have good thermalstability, wetting, foam stability, calcium soap dispersion, good detergency for dirty fabric ofprotein and carbon black, good stability in different electrolyte solutions. The surface tensionsof binary surfactant mixtures of C₁₂AE3P and alkylbetaines were measured by drop volumemethod, and βσand βMof interaction parameters between molecules were calculated. Theresults show that the binary mixed systems have good synergistic effect.The oil/water interfacial tensions of the binary mixed systems of C₁₂AE3P, C₁₈AE₂P,C₁₈AES, C₁₈AESA and alkylbetaines（CAB-1and CAB-2） were measured without adding anyalkaline agent at different temperatures, salinity, hardness and the mixed proportion. Theresults show that the binary mixed systems can reduce interfacial tension of Shengli crudeoil/water to ultralow（an order of10-3mN/m） with the total surfactant concentration in therange of0.05%⁰.3%. The mixed systems have good resistance to salt and heat, but theyhaven’t good resistance to divalent metal ions. The binary mixed systems of C₁₈AESA andCAB-2can reduce interfacial tension of Daqing crude oil/water to ultralow under theconditions of the total surfactant concentration of0.3%, temperature of45℃.