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Enthalpy change on vaporization of aqueous and methanolic formaldehyde solutions
Author(s) -
Liu Y.Q.,
Hasse H.,
Maurer G.
Publication year - 1992
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690381103
Subject(s) - formaldehyde , chemistry , enthalpy , methanol , enthalpy of vaporization , vaporization , aqueous solution , thermodynamics , organic chemistry , physics
A physicochemical model for vapor‐liquid equilibrium in multicomponent formaldehyde‐containing mixtures (Maurer, 1986; Hasse et al., 1990; Hasse and Maurer, 1991a). is extended to describe enthalpy changes upon vaporization. Predicted enthalpy changes are compared with new experimental results. The measurements were carried out with a thin‐film evaporator flow‐calorimeter (Liu and Maurer, 1991). More than 80 experimental data points for mixtures of formaldehyde + water and formaldehyde + methanol + (small amounts of water) are reported. The data cover the temperature range from 323 to 363 K (formaldehyde + water) and 312 to 347 K (formaldehyde + methanol) at liquid phase formaldehyde mole fractions up to about 0.3 (formaldehyde + water) and 0.6 (formaldehyde + methanol). Comparisons between predicted and experimental results for the enthalpy change reveal deviations of only a few percent. Further improvements are achieved by fitting some model parameters, which originally were estimated from noncalorimetric data.