Reaction calorimetry is a subtechnique of calorimetry that is associated with determining the heat produced by specific reactions under study. These reactions can be traditional chemical reactions or other processes that have thermodynamic properties, such as phase changes. Calorimeters give information on the total amount of heat, as well as the rate and kinetics of the reaction. For complex multistep reactions, the calorimeter may be able to provide information about each of the steps in the process for greater insight into the reaction and its kinetics.

In cases in which the heat of reaction is already known, the heat generated by a sample can indicate how far to completeness the reaction has progressed. Typically, reaction kinetics will depend on temperature, pressure and other variables, and most systems provide for environmental control to investigate the dependence of the reaction on these other parameters.

The reaction calorimeter itself can be quite a complex instrument. The primary measurement is heat flow, so some of the most important parts of the instrument are the temperature-control system and the heat-flow measurement. The temperature-control unit can generally support different particular thermodynamic processes, such as adiabatic, isothermal and isoperibolic, or the temperature can be forced to follow a particular profile. However, in addition to the measurement of the heat of reaction, the calorimeter may also include sensors for pH, or even a fiber optic probe so that the contents of the vessel where the reaction takes place can be analyzed by a standalone optical instrument. The vessel can also be a complex component with integrated stirring, and ports for various probes and the introduction of reagents.

The most common application for reaction calorimetry is for understanding how a particular chemical reaction can be scaled up for volume process. While one can often ignore the heat generated by a lab-scale reaction, when carried out at the industrial scale, the heat may be dangerous. Reaction calorimetry allows chemical engineers to identify these dangers ahead of time, so that the process can be managed appropriately.

Thus, reaction calorimetry is very common in the chemicals industry and related fields for which the polymerization reaction is important to understand. Similarly, the technique is used in pharmaceutical processing and bioprocessing. A growing application for reaction calorimetry is in the development of batteries, and other energy storage devices and materials. There are also basic research applications.

Mettler-Toledo is the dominant competitor in the market. There are a number of other vendors, with Parr Instruments being the most prominent. The next tier of suppliers contains a number of medium-sized companies: HEL, IKA, NETZSCH, Setaram, Systag and Thermal Hazard Technology. Smaller participants include Calmetrix, Fauske Associates and Syrris.

Reaction Calorimetry at a Glance:

Leading suppliers

Mettler-Toledo

Parr Instruments

Systag

Largest markets

Chemicals

Polymers

Pharmaceuticals

Instrument cost

$10,000–$125,000