Injection of ethanol into supercritical CO_2: Determination of mole fraction and phase state using linear Raman scattering

Abstract

For the pulsed injection of liquid ethanol into supercritical CO(2) inside an optically accessible chamber, for the first time to the best of our knowledge the spatially and temporally resolving linear Raman scattering technique was used to simultaneously determine the mole fraction and the corresponding phase state in the ethanol jet. The mole fraction was identified by calculating the ratio of the C-H band Raman signal (2950 cm(-1)) of ethanol and the CO(2) Raman signal. The magnitude of this ratio was found to be phase state sensitive. Thus, the phase state of the mixture of ethanol and CO(2) could be classified as being homogeneous liquid, homogeneous supercritical or not yet homogeneously mixed.