Surface properties of surfactants derived from natural products. Part 1: Syntheses and structure/property relationships—Solubility and emulsification

Abstract

Several novel and some previously known, mostly sugar-based, surfactants have been synthesized and some of their surface properties have been characterized and compared with those of commercial nonylphenol ethoxylates. The surfactant solubility in water, ethanol, and dodecane was studied. The properties of these compounds as emulsification agents in systems composed of the surfactant with water/isopropyl myristate, water/rapeseed oil, and water/dodecane are presented. The aqueous solubility of the surfactants follows the general trend expected from their hydrophilic-lipophilic balance according to Griffin (HLBG), but it is also clear that the nature of the headgroup and the structure of the nonpolar part affect the solubility in a manner not captured in the standard HLBG concept. An ester or amine group as the connecting unit between the hydrophile and the hydrophobe produces a more water-soluble surfactant than the corresponding amide derivative. Some effective emulsifiers were found. For instance, the surfactants with a dehydroabietic nonpolar group appear to be promising emulsifiers. Most sugar-based surfactants were able to form macroemulsions of up to around 2 wt/vol% of oil. The stability of many of these emulsions was very high, extending for months.

Surface properties of surfactants derived from natural products. Part 2: Structure/property relationships—Foaming, dispersion, and wetting

“…The major driving force for the surfactant adsorption is the hydrophobic effect, which stems from the fact that water interacts more favorably with itself than with nonpolar molecules or surfaces. The equilibrium contact angle, θ, of the solution droplet on the surface is given by a balance of three interfacial tensions: γ SV − γ SL = γ LV cos θ [1] where γ SV , γ SL , and γ LV are the surface tensions at the solidvapor, solid-liquid, and liquid-vapor interfaces, respectively. For a given solid surface, i.e., a given value of γ SV , the contact angle decreases as the surface tension of the solid-liquid interface is reduced.…”

“…A general introduction to the present investigation of surfactant properties is presented in Part 1 of this study (1). Surfactants 1-30 have been synthesized, investigated, and compared with commercial nonylphenol ethoxylates.…”

“…In this paper, wetting, dispersion, and foaming properties are discussed. Syntheses, solubility, and emulsification properties of the surfactants have already been discussed (1).…”

Synthesis and performance of surfactants based on epoxidized methyl oleate and glycerol

“…These estimates are rein- forced by the water behavior of the products, where the more hydrophilic products form translucent solutions and the more lipophilic one forms a cloudy solution. This places them in the range where they may be considered suitable o/w emulsifiers (33).…”

Overview on Chemical-Based, Bio-based and Natural-Based Surfactants in EOR Applications

“…Furthermore, the impact to the environment can be reduced without lowering the oil production. Although naturalbased surfactants have never been produced commercially, large scale industrial production has been considered [10].…”