Injection of ethanol into supercritical CO2:: Determination of mole fraction and phase state using linear Raman scattering

For the pulsed injection of liquid ethanol into supercritical CO2 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 CO2 Raman signal. The magnitude of this ratio was found to be phase state sensitive. Thus, the phase state of the mixture of ethanol and CO2 could be classified as being homogeneous liquid, homogeneous supercritical or not yet homogeneously mixed. (C) 2007 Optical Society of America