Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Evaluated Enthalpies of Formation of the Stable Closed Shell C1 and C2 Chlorinated Hydrocarbons

Published

Author(s)

Jeffrey A. Manion

Abstract

Experimental data on the enthalpies of formation of chloromethanes, chloroethynes, chloroethenes, and chloroethanes are critically reviewed. Enthalpy of formation values for the C1 and C2 chlorinated hydrocarbons are highly cross-linked by various measured reaction equilibria and currently available sets of values are not internally self-consistent. It is shown that the early static bomb combustion calorimetry studies on highly chlorinated compounds generally give enthalpies of formation that are systematically more positive than later values derivable from rotating bomb combustion or equilibria studies. Those previously recommended values which were based mainly on the early static bomb work therefore need substantial revision. On the basis of more recent literature data obtained with rotating bomb combustion calorimetry, together with analysis of literature data on reaction enthalpies and equilibria involving chlorinated hydrocarbons, an updated self-consistent set of {Δ}fH [298.15K] values for closed shell chlorinated C1 and C2 hydrocarbons (25 compounds) is recommended. Data on the enthalpies of vaporization are also reviewed and values of δvapH[298.15 K] and δvapH [298.15 K] are recommended. The presently suggested enthalpies of formation for highly chlorinated alkenes and alkenes (particularly C2Cl4, C2HCl3, C2HCl5 and C2Cl6) are significantly (8-15 kJ mol-1) more negative than given by most previous evaluators. Values for the chloroethyes are 10-25 kJ mol-1 more positive than given in previous reviews and more limited changes are suggested for other compounds in the series.
Citation
J. Phys. & Chem. Ref. Data (JPCRD) -
Volume
31
Issue
No. 1

Keywords

chloroethanes, chloroethenes, chloroethynes, chloromethanes, enthalpy of formation, heat of formation, heat of vaporization

Citation

Manion, J. (2002), Evaluated Enthalpies of Formation of the Stable Closed Shell C1 and C2 Chlorinated Hydrocarbons, J. Phys. & Chem. Ref. Data (JPCRD), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=831727 (Accessed April 14, 2024)
Created March 1, 2002, Updated November 14, 2018