The CHETAH program is a unique tool for predicting both thermochemical properties and certain "reactive chemicals" hazards associated with a pure chemical, a mixture of chemicals, or a chemical reaction. This is accomplished through a knowledge of only the molecular structure(s) of the components involved by an implementation of Benson's method of group additivity. CHETAH is useful for classifying materials for their ability to decompose with violence, for estimating heats of reaction or combustion, and for predicting lower flammable limits and certain other flammability parameters.
For thermochemical estimations, CHETAH is designed to conveniently and accurately calculate several important properties as a function of temperature for pure materials, mixtures, and reactions. For hazard evaluation, CHETAH is designed to be a CONSERVATIVE screening tool for use during the early stages of compound synthesis or process development. Its use should be integrated within an experimental program for testing reactive chemical hazards. CHETAH WAS NOT DESIGNED TO REPLACE THE PHYSICAL TESTING OF MATERIALS. Rather, CHETAH's computational results should be used to complement experimental results to help identify the need for further testing in the areas of impact sensitivity and/or flammability.
The potential hazards associated with handling new chemicals will not, in general, be known a priori. Furthermore, experimentally determined thermochemical data for new chemicals used for process design and to predict hazards will often not be available. CHETAH exists largely to allow users to build compounds using group additivity methods, to predict thermochemical properties for compounds and reactions, and to use these predicted properties for hazard evaluation. Users may then use CHETAH's predictions along with results from Accelerating Rate Calorimetry (ARC), Differential Scanning Calorimetry (DSC), flash point, dust explosion, drop-weight, or other tests to prepare, use, store, or dispose of new compounds safely. Personnel committed to ensuring the safe operations at sites where research, process development, or manufacturing occur should include CHETAH in their Reactive Chemicals evaluation programs.
CHETAH also is of utility for predicting thermochemical properties of materials such as standard enthalpies of formation, heat capacities, entropies, and free energies of formation. Thermodynamics properties of user specified reactions can also be calculated. Extensive databases of thermodynamic properties for gas phase molecules, species in aqueous solution, and ionic solids are provided. CHETAH also allows the prediction of solid and liquid thermodynamic properties.
For purchase information concerning CHETAH please contact ASTM International .