J. Masamoto et al., DEVELOPMENT OF A NEW ADVANCED PROCESS FOR MANUFACTURING POLYACETAL RESINS .2. VAPOR-LIQUID-EQUILIBRIUM OF FORMALDEHYDE WATER-SYSTEM, Journal of applied polymer science, 50(8), 1993, pp. 1307-1315
To develop a new technology for the purification of formaldehyde from
formalin by a distillation method, the vapor-liquid equilibrium of for
maldehyde-water binary systems was investigated. Based on the studies
of Thompson et al. and Iliceto et al., the vapor-liquid equilibrium of
formaldehyde and water are calculated and these calculations are in g
ood agreement with the reported data. It was found that the vapor pres
sure of formaldehyde is determined by the free formaldehyde concentrat
ion (mol/L), whereas the vapor pressure of water is determined by the
molar ratio of free water. The vapor liquid equilibrium of formaldehyd
e-water in the presence of a diluent was also investigated. It was sho
wn by calculation that in some cases, when the concentration of the di
luent is high, the volatility of formaldehyde is always higher than th
at of water and these calculations are in good agreement with experime
ntal data. Based on this principle, the purification of formaldehyde b
y an extraction distillation method was established. (C) 1993 John Wil
ey & Sons, Inc.