Multiple phase transitions in palmitoleic acid under the pressure

Long unsaturated carbon chain liquids exhibit a phase transition under a high pressure. We have investigated the phase transition in palmitoleic acid as a representative of this group not researched yet. A temperature, a relative permittivity and a dissipation factor have been measured, while the pressure was applied. We have also observed the transmitted and the scattered IR light. These parameters allowed us to find phase transitions that occurred due to the pressure. Especially the behavior of the temperature indicates several phase transitions during compression. Above certain pressure the liquid becomes opaque, it is connected with most significant phase transition that occurs around 177 MPa. We have observed asymmetry of intensity of the scattered light, which is much stronger during decompression. Observed multiple phase transitions are not present in other acids investigated by us.