David J. Frurip

Prediction of thermal hazards of chemical reactions

Abstract A large number of products of the chemical industry are produced using potentially hazardous reactions. The experimental investigation of the hazards of all reactions involved in production processes would be very expensive. The primary reactions—desired reactions which are part of the process—and the secondary reactions—undesired successive or side reactions—should both be considered. In this paper the methods of prediction of thermodynamic and kinetic properties of reactions are discussed. Thermodynamic data are of eminent practical importance because low heats of reaction may indicate that no further experimental investigations are necessary. For primary reactions, e.g. polymerization, diazotization and hydrogenation reactions, reaction enthalpies have been obtained by experimental methods. Typical data can be found in the public literature for the different reaction classes. When compared with theoretical thermodynamic data estimated by the chetah computer program, the agreement is satisfactory. chetah implements Bensons second-order group contribution technique ( Benson, 1976 ). For secondary reactions, especially exothermic decomposition reactions, typical heats of reaction—mostly measured by DSC—have been associated with functional groups. Decompositions and other undesired exothermic reactions that proceed from the same functional group, e.g. a nitro group, have about the same heat of reaction. For the estimation using the chetah program, decomposition reactions have to be assumed which are typical for the functional group. The reaction yielding the maximum exothermic reaction energy was selected. The comparison of experimental heats of reaction with estimated data shows satisfactory agreement. In principle it is also possible to predict kinetic data of secondary reactions, but sufficient experimental data are missing.

The role of ASTM E27 methods in hazard assessment. Part II: Flammability and ignitability

Accurate flammability and ignitability data for chemicals form the cornerstone of procedures used to assess the hazards associated with commercial chemical production and use. Since 1967 the ASTM E27 Committee on the Hazard Potential of Chemicals has issued numerous, widely used consensus standards dealing with diverse testing and predictive procedures used to obtain relevant chemical hazard properties. The decision to issue a standard rests solely with the membership, which consists of representatives from industry, testing laboratories, consulting firms, government, academia, and instrument suppliers. Consequently, the procedures are automatically relevant, timely, and widely applicable. The purpose of this paper is to highlight some of the widely used standards, complemented with hypothetical but relevant examples describing the testing strategy, interpretation, and application of the results. A further goal of this paper is to encourage participation in the consensus standards development process.

Effective use of differential scanning calorimetry in reactive chemicals hazard evaluation

DSC (differential scanning calorimetry) is one of the most commonly applied thermal stability testing methodologies in reactive chemicals hazard evaluation. This is certainly because of many factors, including the relative low cost of the equipment, rapid turnaround time of experiments, small sample size, ease of interpretation, relative accuracy of the calorimetric results, and the wide range of temperatures over which a DSC can operate. Traditionally DSC is mainly used as a screening method used to identify possible energy release hazards, which may require further, more sophisticated testing to elucidate and quantify the actual hazard. Practitioners have learned to maximize the information obtainable from DSC testing. This article highlights how DSC is applied to routine day‐to‐day hazard screening and summarizes the collective knowledge of Dow in this area for over 20 years. Some applications discussed include: recognizing thermal events from peak shape, high energy materials, chemical compatibility, and eliminating unnecessary testing. Also presented are examples of the limitations of DSC and examples where it should not be used. Finally, this article discusses how DSC may be used to estimate reaction kinetics by quantitative thermokinetic modeling.

The role of ASTM E27 methods in hazard assessment: Part I. Thermal stability, compatibility, and energy release estimation methods

Accurate reactive chemicals data form the cornerstone of procedures used to assess the hazards associated with commercial chemical production and use. Since 1967, the ASTM E27 Committee on the Hazard Potential of Chemicals has issued numerous, widely used consensus standards dealing with diverse testing and predictive procedures used to obtain relevant chemical hazard properties. The decision to issue a standard rests solely with the membership, which consists of representatives from industry, government, consulting firms, and instrument suppliers. Consequently, the procedures are automatically relevant, timely, and widely applicable. The purpose of this paper is to highlight some of the widely used standards, complemented with hypothetical but relevant examples describing the testing strategy, interpretation, and application of the results. A further goal of this paper is to encourage participation in the standards development process.

Establishing benchmarks for the first industrial fluids simulation challenge

In order that the entries in the first industrial fluid properties simulation challenge could be judged, a benchmarking committee comprised of the authors of this paper was established. The mandate of the committee was to determine best values for the physical property questions posed in the challenge based on a thorough evaluation of the available literature and on new experimental measurements, as necessary. A key part of the activity was to determine robust estimates of uncertainty for the benchmarks, as these also played a role in the evaluation of challenge entries.

Reactive chemicals emergency response and post-event calorimetric testing

A serious upset in process conditions may result in a Reactive Chemicals incident. In such an emergency, procedures must be implemented to prevent injuries, mitigate the event and minimize property loss and/or environmental release as dictated by the required facility Emergency Plan. This article describes the process the Dow Chemical Company uses for engaging Reactive Chemicals experts in an emergency situation. In order to be effective, the Reactive Chemicals expert must have or be provided with in‐depth knowledge of the process streams and raw materials involved. The information is crucial for understanding what is happening, what might happen in the immediate future, and what can be done to successfully mitigate the Reactive Chemicals incident. Following the incident, calorimetric experiments are typically performed to confirm or refute the hypotheses of what caused the event; additionally, the experiments provide information as to reactive chemicals hazards that may potentially still exist in the process streams. The aforementioned process will be illustrated by describing an actual event.