Microwave-assisted low-cost synthesis of sucrose-soya ester from vegetable oil refinery by-product and its application in toothpaste formulation for oral hygiene

The major drawbacks of the sucrose ester (SE), in spite of being a green nonionic surfactant, are the difficulty of synthesis and higher cost. Distilled soya acid oil (DSAO) obtained as by-product from a vegetable oil refinery was used for the synthesis of fatty acid methyl ester (SAFAME). Microwave-assisted method (680 watts system), which is greener and more efficient was used for the synthesis of SAFAME at 99.3% conversion using 2 wt% sulfuric acid catalyst within 30 min as well as for the synthesis of SE at 82.5% conversion using 5 wt% K2CO3 catalyst within 45 min. Both synthesis steps were monitored and characterized by using thin-layer chromatography, gas chromatography, H-1 NMR, and FT-IR. The surface tension of 1% aq. solution of SE was 29.58 mN m(-1), while the interfacial tension of n-heptane-1% aq. solution was observed to be 3.29 mN m(-1). The critical micelle concentration was 74.24 mg L-1. Foaming properties, emulsion stability, and wetting power were determined by using standard techniques. The SE was used for the development of desensitizing anticavity toothpaste formulation and the various properties were evaluated in comparison with the commercial toothpaste formulation available in the market. The results show that the partially renewable surfactants like sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) can be replaced partially or fully with the biobased renewable SE surfactants in the various personal care formulations including toothpaste.