EXPERIMENTAL-DETERMINATION OF THE SPINODAL P-T-X SURFACE FOR THE SYSTEM 2-BUTOXYETHANOL WATER USING THE PPICS APPARATUS

The PPICS (Pressure Pulsed Induced Critical Scattering) apparatus has been used in conjunction with the light scattering theory of Debye and Scholte to investigate the spinodal and binodal characteristics of th e 2-butoxyethanol + water system in pressure-temperature-composition s pace. Data have been obtained at 2-butoxyethanol concentrations rangin g from 17 to 40 wt%, and pressures up to 200 bar. Corrections were mad e to counter the effects of solution turbidity and background scatter. The trends observed were consistent with previous studies and the kno wn phase envelope geometry. It was observed however that the system wa s particularly sensitive to the purity of the 2-butoxyethanol. Trends in the spinodal data obtained at 1 bar were observed to differ signifi cantly from that published by Wenzel et al. (1980). Possible reasons f or this discrepancy are discussed.