Synthesis And Performances Of Oil-based Surfactants Dodecanoyl Diphenyl Ether Sulfonates

Synthesis of dodecyl diphenyl ether sulfonate has much drawbacks such as longsynthetic route, high cost, large amount of waste, etc. For solving these problems, thesynthetic strategy of novel surfactant dodecanoyl diphenyl ether sulfonate was developed.Firstly, the direct Friedel-Crafts acylation of dodecanoic acid and diphenyl ether was studied,with dodecanoyl diphenyl ether as product. Then the sulfonation and disulfonation ofdodecanoyl diphenyl ether was carried out, abtaining two novel oil-based surfactants sodiumdodecanoyl diphenyl ether sulfonate （MMS） and disulfonate （MDS）. Lastly, the surfaceactivity, electrolyte resistance and application performances of those two novel surfactantswere investigated.The P₂O₅/SiO₂was introduced in Friedel-Crafts acylation of dodecanoic acid withdiphenyl ether, FT-IR and1H-NMR data confirmed that dodecanoyl diphenyl ether wasabtained sucessfully. By studying the different way of catalyst preparation, we comfirmed thatthe SiO₂acting as an promoter. Reaction condition of acylation was optimized. Under thecondition: n（diphenyl ether）: n（dodecanoic acid）: n（P₂O₅）=2.5:1:2,60oC,5h, convertionrate of dodecanoic acid was up to94%.Sulfonation of dodecanoyl diphenyl ether was studied, with sodium dodecanoyl diphenylether sulfonates as products. FT-IR and1H-NMR data confirmed that two new sulfonatesurfactants were obtained successfully, namely sodium dodecanoyl diphenyl ether sulfonate（MMS） and sodium dodecanoyl diphenyl ether disulfonate （MDS）, which had no CASnumbers. When n（chlorosulfonic acid）: n（dodecanoyl diphenyl ether）=1.5:1, product wasmostly monosulfonate, when the ratio rised to5:1, disulfonate became the major.Post-sulfonation time of sulfonation was optimized. Highest sulfonating rate of dodecanoyldiphenyl ether （94.5%） was abtained under the optimized post-sulfonation time5h,n（chlorosulfonic acid）, n（dodecanoyl diphenyl ether）=1.5:1,45oC.Surface activity, electrolyte resistance and application performance such as calciumstability, lime soap dispersing power （LSDP）, detergency, wetting time, foam ability andemulsifying ability were measured. Both novel surfactants possess excellent low temperaturesolubility （TK<0oC） and outstanding resistance to hard water and electrolytes. MMS hasstrong lime soap dispersing power （LSDP=6.5） and good detergency comparable to that ofLAS, thus it could potentially be used as new lime soap dispersant and detergent. MDS hasalmost the same detergency ability with that of dodecyl diphenyl ether disulfonate as well asLAS, along with extraordinary low foam （nearly no foam）. So it could be used as low foamdetetergent or other low foam products.