In response to Gary Buske's excellent letter regarding heat of reaction calculations to evaluate the thermal hazard of magnesium nitride in water, there are several good resources available to interested researchers for calculating heats of reaction and assessing reactive chemical hazards in general (C&EN, July 13, page 2). In addition to our extensive internal databases and resources, we find the following external resources to be useful within Dow's Reactive Chemicals organization:
1. NIST WebBook (webbook.nist.gov/chemistry). This free resource provides a wealth of physical property information for various chemicals. The heats of formation for many compounds can be located here, which in turn can be used to calculate heats of reaction.
2. CHETAH (www.chetah.usouthal.edu). This software will estimate various chemical thermodynamic properties, including reaction heats, and is an excellent complement to NIST's resource when literature values for the heat of formation are unknown. Key contact: Keith Harrison at email@example.com.
3. "Determination of Reaction Heat: A Comparison of Measurement and Estimation Techniques," Gerald A. Weisenburger et al. (Org. Process Res. Dev. 2007, 11, 1112).This paper provides a nice overview of a step-by-step procedure (originally developed and published by Dow in the 1990s) for calculating heats of reaction and includes a table of estimated and measured heats of reaction for 50 reactions.
4. Strategies for an overall reactive chemical hazard assessment based on scale and energy release potential have been described in "Selection of the Proper Calorimetric Test Strategy in Reactive Chemicals Hazard Evaluation," David J. Frurip (Org. Process Res. Dev. 2008, 12, 1287).
We hope that others will find these resources helpful for calculating heats of reaction as part of a standard procedure for understanding and controlling potential reactive chemical hazards. In addition to the above-mentioned sources, we would be happy to provide additional references and resources for any interested readers.