Preparation And Performance Of Polyoxyethylene Ether Sulfonates With Different Hydrophobic Groups

Alkyl alcohol（phenol）polyoxyethylene ether sulfonates,which possess the characteristics of salt-tolerant from nonionic surfactants and temperature-resistant from sulfonate anionic surfactants,have aroused widespread concern in the scientific studies for high temperature and high salinity oil reservoir.In this paper,polyoxyethylene ether sulfonates with differerent hydrophobic groups were synthesized with polyoxyethylene ether with differerent hydrophobic groups and sodium isethionate as sulfonation agents.The effects of hydrophobic chains,EO group,PO group,ionic headgroups(-COONa,-SO4 Na and-SO3 Na,corresponding surfactant abbreviation being C_12-14E₃ C,C_12-14E₃ S and C_12-14E₃SO)and counterions(Na+,K+,Mg²⁺and Ca²⁺)on surface/interface activity were investigated.Anionic surfactants used in high temperature and high salinity oil field were overviewed,and the research progress on synthesis and application of alkyl alcohol（phenol）polyoxyethylene ether sulfonates were reviewed.Sodium fatty alcohol polyoxyethylene ether sulfonates（CmEnSO）,sodium iso-tridecanol polyoxyethylene ether sulfonates(C₁₃E₆SO)and C_12-14 fatty alcohol polyoxyethylene ether sulfonates with different counterion(C_12-14E₄SO-M,M=K,Mg and Ca)were synthesized.The products were characterized by 1H-NMR and ESI-MS.The effects of hydrophobic chains,EO group,ionic headgroups and counterions on surface tension,interfacial tension（IFT,surfactant/inorganic salt/dodecane system）,wetting,foam performance and thermal stability were studied.The results are as follows:（1）with increasing the length of the hydrophobic group,critical micelle concentration（cmc）and foaming ability decrease,IFT decreases first and then increases,surface tension at cmc（γcmc）and wetting time increase,and thermal stability has no significant change;（2）with increasing branching degree of hydrophobic chain,cmc and γcmc increase,and IFT,foam stability,thermal stability and wetting time decrease;（3）with increasing EO number,cmc and foam performance have no significant change,γcmc,IFT,wetting time and thermal stability increase;（4）cmc and γcmc decrease in the order C_12-14E₃SO>C_12-14E₃S>C_12-14E₃C;the difference of IFT among C_12-14E₃ S,C_12-14E₃ SO and C_12-14E₃ C decreases with increasing the NaCl concentration;for surfactant/CaCl₂/dodecane system,IFT increases in the order C_12-14E₃C<C_12-14E₃S<C_12-14E₃SO;foaming ability of C_12-14E₃ C is higher than that of C_12-14E₃ SO and C_12-14E₃S;wetting time of C_12-14E₃ C and C_12-14E₃ S is shorter than that of C_12-14E₃SO;thermal stability decreases in the order C_12-14E₃C>C_12-14E₃SO>C_12-14E₃;（5）the cmc and γcmc of C_12-14E₄SO-Ca and C_12-14E₄SO-Mg are lower than that of C_12-14E₄ SO and C_12-14E₄SO-K;IFT among C_12-14E₄SO-M has no significant difference upon adding NaCl or CaCl₂;foaming ability and thermal stability of C_12-14E₄SO-Mg and C_12-14E₄SO-Ca are higher than that of C_12-14E₄ SO and C_12-14E₄SO-K;wetting time of C_12-14E₄SO-Mg and C_12-14E₄SO-Ca is shorter than that of C_12-14E₄ SO and C_12-14E₄SO-K.Diffusion coefficient（D）decreases with increasing surfactants concentration.IFT decreases upon adding NaCl or CaCl₂.Sodium nonylphenol polyoxyethylene ether sulfonates（NPEnSO）,sodium polyoxypropylene-polyoxyethylene ether sulfonates（NPPmEnSO）and sodium cardanol polyoxyethylene ether sulfonates（NSF-nSO）were synthesized.The products were characterized by HPLC,1H-NMR and ESI-MS.The effects of EO group and PO group on surface tension,IFT（surfactant/inorganic salt/dodecane system）,wetting,foam performance and thermal stability were studied.The results are shown as follows: with increasing EO number,cmc and foam performance have no significant change,γcmc,IFT,wetting time and thermal stability increase;inserting 2 or 3 PO into NPE₃ SO,cmc,γcmc,IFT,foaming ability,wetting time,and thermal stability increase;D decreases with increasing surfactants concentration;IFT decreases upon adding NaCl or CaCl₂;foaming ability of NSF-nSO is lower than that of NPEnSO;wetting time of NSF-nSO is longer than that of NPEnSO.Solution stability of mixture of polyoxyethylene ether sulfonates with different hydrophobic groups and cationic surfactant dodecyltrimethylammonium chloride（DTAC）and IFT between mixed surfactant solution and dodecane were investigated.Solution stability was determinated through the transmittance rate and the results show that increasing EO number could improve the stability of the mixture systems.Effects of surfactants structure,molar ratio of anionic surfactant/cationic surfactant,temperature and concentration of surfactant on the IFT were investigated,and the results show that:IFT has minimum value at 6/4 to 4/6 of molar ratio of anionic/cationic surfactant;IFT of C_12-14E₃SO/DTAC,C18E6SO/DTAC and C_12-14E₃S/DTAC of equal molar ratio increaseswith increasing the temperature,and IFT of other mixture system isn’t sensitive to temperature;IFT decreases first and then increases or keeps no change with increasing surfactant concentration;IFT increases with increasing the EO number or inserting 2 and3 PO number into NPE₃SO;IFT decreases with increasing branching degree of hydrophobic chain;IFT of C_12-14E₃S/DTAC is lower than that of C_12-14E₃SO/DTAC and C_12-14E₃C/DTAC;IFT of C_12-14E₄SO-M/DTAC has no significant difference;IFT decreases with increasing the hydrophobic chain length of cationic surfactant or changing the single hydrophobic chain to double hydrophobic chain;IFT of C_12-14E₄SO/DTAC=5/5has no significant change after dynamic adsorption on quartz sand.IFT between polyoxyethylene ether sulfonates with different hydrophobic groups and crude oil from Zhongyuan oil field was investigated.The studied polyoxyethylene ether sulfonates have good solubility in high salinity formation water,and increasing the EO number and inserting 2 or 3 PO groups into NPE₃ SO improve the ability of salinity-tolerant.Effects of hydrophobic chains,EO group,PO group,ionic headgroups and counterions on IFT between surfactants solution and crude oil were investigated,and the results are as follows: IFT decreases with decreasing the EO number and increasing branching degree of hydrophobic chain;IFT decreases first and then increases with increasing the hydrophobic chain and PO number;IFT decreases in the order C_12-14E₃C>C_12-14E₃SO>C_12-14E₃S;IFT among C_12-14E₄SO-M has no significant difference;IFT for NPE₃ SO,NPPmE₃SO and C16E6 SO reaches 10-2 mN/m order of magnitude,and IFT for other sulfonate surfactants is higher than 0.1 mN/m;IFT is insensitive to dilution of surfactants,which may attribute to lower cmc.There is a synergistic effect between C_12-14E₄ SO and cationic surfactants（DTAC and DDAC）in reducing IFT,and IFT for C_12-14E₄SO/DDAC could reach 10-3 mN/m order of magnitude.