Raman Spectroscopic Studies of Pressure-Induced Phase Transitions on 1-Dodecene

Raman spectroscopic features of 1-dodecene are studied in a moissanite anvil cell up to 3.0GPa at 21°C. Our data indicate that 1-dodecene is chemically stable under the experimental condition because no new Raman peaks can be observed. However, two significant discontinuities in the plots of Raman shift versus pressure indicate two phase transitions of 1-dodecene. One is liquid--solid transition at pressure of about 500MPa, the other is solid--solid phase transition at pressure from 1300 to 1550MPa. The latter is considered to be related to the orientational change of the plane structure of ethylene. A
rudimentary phase diagrams for 1-dodecene, n-pentane, n-hexane are
proposed based on the results and previous data.