Microemulsion formation of triglyceride oils at ambient conditions (temperature and pressure) and without the addition of co-oil and/or alcohols is challenging at best. Undesirable phases, such as macroemulsions, liquid crystals and sponge phases, are often encountered when formulating triglyceride microemulsions. The purpose of this study is to investigate the use of extended surfactants, lipophilic linkers, and hydrophilic linkers in enhancing triglyceride solubilization and interfacial tension reduction. We have studied two classes of extended surfactants, linear alkyl polypropoxylated sulfate (LAPS) surfactants and linear alkyl polypropoxylated ethoxylated sulfate (LAPES) surfactants. Linkers evaluated were oleyl alcohol (lipophilic linker), sodium mono and dimethyl naphthalene sulfonate (SMDNS), and polyglucoside (hydrophilic linkers). Oils studied include olive, peanut, soybean, canola and sunflower oils. The effect of electrolyte concentration on microemulsion phase behavior was studied. The microemulsion ''fish'' diagram was obtained by plotting the total surfactant and linker concentrations versus the electrolyte concentration.We were able to form Winsor Type I, II, III and IV microemulsions at ambient conditions and without co-oil or short and medium chain length alcohol addition. Winsor Type III and IV triglyceride microemulsions are particularly useful in numerous applications such as cosmetics, vegetable oil extraction and soil remediation.

The use of hexane to extract vegetable oil from oilseeds is of growing concern due to hexane's environmental impact and because of worker exposure concerns. The goal of our work is to demonstrate that the aqueous extended-surfactant-based method is a viable alternative for vegetable oil extraction. In our method, ground oilseeds were dispersed in the aqueous surfactant solution, allowing the oil to be liberated from the seeds as a separate phase from the aqueous phase. The impact of pH, shaking intensity, shaking time and seed to liquid ratio on oil yield are presented. Extended-surfactants are a new type of surfactant with propoxylate (PO) and/or ethoxylate (EO) groups inserted between the hydrophilic head and the hydrophobic alkyl chain of the surfactant molecule. This unique structure of extended-surfactants enables them to produce ultralow interfacial tension with vegetable oils. We have found that at low aqueous concentrations (less than 0.3 wt%), extended-surfactant solutions are able to produce ultralow interfacial tension between aqueous extraction and vegetable oil phases. At optimum condition (seed to liquid ratio of 1-5, 30 min extraction at 150 shakes/min and 30 min centrifugation at 2,1709g) we achieved 93-95% extraction efficiency for peanut and canola oils at 25°C. The oil quality produced from the aqueous extended-surfactant-based method was found to be comparable or even superior to that obtained from hexanebased extraction, further demonstrating the viability of aqueous extended-surfactant based extraction.

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In spite of the increasing interest in cold temperature detergency of vegetable oils and fats, very limited research has been published on this topic. Extended surfactants have recently been shown to produce very promising detergency with vegetable oils at ambient temperature. However, the excessive salinity requirement (4-14 %) for these surfactants has limited their use in practical applications. In this work, we investigated the mixture of a linear C 10 -18PO-2EO-NaSO 4 extended surfactant and a hydrophobic twin-tailed sodium dioctyl sulfosuccinate surfactant for cold temperature detergency of vegetable oils and semi-solid fats. Four vegetable oils of varying melting points (from -10 to 28°C) were studied, these were canola, jojoba, coconut and palm kernel oils. Anionic surfactant mixtures showed synergism in detergency performance compared to single surfactant systems. At temperatures above the melting point, greater than 90 % detergency was achieved at 0.5 % NaCl. While detergency performance decreased at temperatures below the melting point, it was still superior to that of a commercial detergent (up to 80 vs. 40 %). Further, results show that the experimental microemulsion phase behaviors correlated very well with predictions from the hydrophilic-lipophilic deviation concept.

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