Thermodynamic and Ab initio analysis of the controversial enthalpy of formation of formaldehyde

Abstract

There are two values, -26.0 and -27.7 kcal mol-1, that are routinely reported in literature evaluations for the standard enthalpy of formation, ΔfH°298, of formaldehyde (CH 2=O), where error limits are less than the difference in values. In this study, we summarize the reported literature for formaldehyde enthalpy values based on evaluated measurements and on computational studies. Using experimental reaction enthalpies for a series of reactions involving formaldehyde, in conjunction with known enthalpies of formation, its enthalpy is determined to be -26.05± 0.42 kcal mol-1, which we believe is the most accurate enthalpy currently available. For the same reaction series, the reaction enthal..