Phase behavior of aqueous systems of monoglycerides

Monoglyceride-H2O systems in the range above about 5% H2O exhibit a varied phase behavior with a number of mesomorphic states reminiscent of those found for soap-H2O systems. There are fluid neat, stiff and “short” viscous isotropic, and plastic or stringy middle states. In the case of saturated monoglycerides, neat states prevail at low molecular weight as with monolaurin, but viscous isotropic and finally middle states appear at higher chain length as with monoarchidin and monobehenin. The phase diagrams for systems of unsaturated compounds resemble those for systems of saturated compounds, with corresponding phase regions occurring at lower temperatures. The monoelaidin-H2O system closely resembles a shifted monostearin-H2O system, neither system showing middle. Middle phase appears in a small island for monoolein and monolinolein near 90C and 20% water. Water dissolves negligible amounts of monoglycerides so that phases which are nearly 100% H2O exist for substantially all systems and conditions when H2O content is 60% or more.