Synthesis of Dodecyl Lauroyl Benzene Sulfonate and its Application in Enhanced Oil Recovery

Abstract

Abstract A new hydrophobic surfactant, dodecyl lauroyl benzene sulfonate (DLBS), was synthesized and its application in enhanced oil recovery by alkali-surfactant-polymer (ASP) flooding was studied. The results show that DLBS can be synthesized by reaction of industrial dodecyl benzene with lauroyl chloride in the presence of AlCl3, followed by sulfonation with ClSO3H and neutralization with NaOH. The lauroyl-group is confirmed to be connected to the para-position of the alkylbenzene by 1HNMR spectrum. The synthesized DLBS is well soluble in pure water and reservoir (connate) water at 45°C. It is highly surface active which is indicated by its low CMC of 1.1 · 10−5 mol/L, and its low surface tension, γcmc of 28.6 mN m−1. By mixing with heavy alkylbenzene sulfonates of relatively low average molar mass (387 g mol−1) at a total surfactant concentration of 5 mM, DLBS can reduce the interfacial tension of Daqing crude oil/connate water to an order of 10−3 mN/m at 45°C in the presence of 0.5–1.0 wt.% NaOH and 1000 mg L−1 of polymer. If the NaOH was replaced by a gentle alkaline salt, Na2CO3, certain amounts of dodecyl dimethyl carboxy betaine were added and the concentration of Na2CO3 was increased to 1.2–2.0 wt.%, the interfacial tension of Daqing crude oil/connate water can also be reduced to an ultralow value. Therefore DLBS is a good hydrophobic surfactant applicable in ASP flooding with either NaOH or Na2CO3 as alkaline agents.