Novel ethoxylated surfactants from low-value refinery feedstocks

The synthesis, characterization, surface activity and potential applications of ethoxylated surfactants derived from low-value refinery feedstocks, a propane-precipitated asphaltene stream (PDA), catalytic cracked tars and petroleum tars, are presented. The new tensoactive compounds were synthesized by an alkali-catalyzed ethoxylation reaction (135–150°C, 20–60 psi) and were characterized by molecular weight determinations, elemental analysis, FT-IR, and 1H NMR. Several novel surfactants were prepared with different ethylene oxide/hydrocarbon molar ratios (from 2 up to 50) for each refinery stream. The interfacial properties were studied using a toluene/water model system and a minimum value of interfacial tension (0.01 dyn/cm) was obtained for a 12-ethoxylated PDA tensoactive compound. The results indicated that the new surfactants have potential applications for enhanced oil recovery (crude oil/formation water interfacial tension of approximately 0.1 dyn/cm) and as stabilizing agents for crude oil-in-water emulsions (minimum mean droplet size of 36 μm).