Synthesis And Application Performance Of Quaternary Ammonium Gemini Surfactants

Sulfur compounds are present in the fuel oil like gasoline and diesel etc,they will generate Sulfur oxides (SOX),which is the main source of pollution through the atmosphere. SOX will corrupt the combustion chambers and exhaust system of the engine, accelerate the deterioration of motor vehicle engine, lubricating oil. Therefore, many countries have enacted strict sulfur standard on fuel oil, China has gradually implemented50μg/g sulfur content standard on vehicle fuel oil, So the research of desulfurization technology on fuel oil will be more and more concern and attention.To remove sulfur components in diesel fuel, which is one of factors that causes the formation of acid rain, deep desulfurization technology for sulfides removal is investigated. Oxidative desulfurization reaction is a heterogeneous reaction, its rate is slow and causes the poor desulfurization effect, so quaternary ammonium surfactant as the phase transfer catalyst is added to the reaction system, which can bring peroxy acid to the oil phase, On the other hand, can reduce the interfacial tension which can let the oil phase and the aqueous phase contact more fully, to accelerate the reaction rate and improve the desulfurization rate.Gemini surfactant with special structure has many excellent features, therefore,author synthesized double-quaternary ammonium surfactants DAEQ9-CI as a phase transfer catalyst, made the research on desulfurization rate evaluation for hydrogen peroxide/acetic acid oxidation system, screened the suitable reaction conditions for system of desulfurization of diesel oxidation, main contents are as follows:1. Gemini Surfactants (DAEQn-Cl) containing polyoxyethylene ether quaternary ammonium is synthesized with AEOn, Thionyl chloride, tetramethylethyIenediamine as raw material, through nucleophilic substitution reaction and quaternization.2. The optimal reactive conditions for intermediate AEQ9-CI is screened by single factor and orthogonal experiments:DMF as solvent is100mI, the molar ratio of SOCI2and AEO9is1.8:1, reaction time is6h, reaction temperature is85℃; suitable reaction conditions for synthesis of DAEQ9-C1is selected by the single factor:the molar ratio of chlorinated lauryl alcohol and N, N-four methyl ethylenediamine is2.4:1, reaction temperature is70℃, reaction time is2d, the ethanol is60mL.3. Gemini surfactant for DAEQ9-CI is characterized by infrared spectroscopy and nuclear magnetic resonance spectra.4. At room temperature, the surface activity for DAEQn-CI is determined by JZhy-180interfacial tension Instrument, critical micelle concentration for DAEQ9-CI is0.0187x 10-3mol/L, Ycmc is28.2mN/m.5. The oil-water interfacial tension of DAEQ9-C1is measured by Spinning drop TX-500interfacial tension instrument, the oil-water interfacial tension for DAEQ9-CI between certain concentration for Nanchong refinery straight-run diesel can be decreased to10"2mN/m orders of magnitude.6. The compound properties of DAEQ9-CI is measured through conventional surfactants SDS, CTAB, OP-10, experiment shows the mixture ratio for DAEQ9-CI and SDS is3:7, CMC is0.0079x10-3mol/L, y cmc is26.8mN/m; the mixture ratio for DAEQ9-C1and CTAB is4:6, CMC is0.0063x10-3mol/L, y cMc is28.1mN/m; mixture ratio for DAEQ9-CI and OP-10is4:6, CMC is0.0071x10-3mol/L, γ cMc is26.6mN/m.7. Emulsifying properties resistance to salt and wettability for DAEQ9-CI solution in a hydrophilic (or hydrophobic) on the slides are studied. results show that DAEQ9-C1has the best emulsification capability when the ratio of oil to water is7:3, and stability of emulsion is very good, Interfacial tension of DAEQ9-CI solution for Zhongyuan crude oil during the temperature range of30~80℃are maintained at10"2mN/m magnitude, and the addition of NaCl and CaCI2can reduce the oil-water interfacial tension.8.The optimum conditions and the desulfurization rate of H2O2/CH3COOH, H2O2/CH3COOH/CTAB, H2O2/CH3COOH/DAEQ9-CI for oxidative desulfurization of diesel are determined, the best effect of oxidation desulfurization for diesel by H2O2/CH3COOH/DAEQ9-CI catalytic system is determined when V (diesel) is25mL, the speeding condition is300r/min, V (H2O2)/V (CH3COOH) is0.5, quantity for DAEQ9-CI is0.06%, reaction time is60min, temperature is40℃, V (oxidation system)/V (diesel) is0.8, desulfurization rate is96.7%. Experiments show that the synthesis of phase transfer catalyst for DAEQ9-CI will have an excellent application.9. Product after Diesel oxidation is extracted by four different extractants, extraction agent through the final desulfurization rate and diesel yield is selected for different oxidation system.