What is reaction calorimetry?

Reaction calorimetry measures the heat released from a chemical reaction or physical process and provides the fundamentals of the thermochemistry and kinetics of a reaction.

The information obtained is essential to describe the heat release of a chemical reaction over time, and to safely transfer it from lab to plant.

Reaction calorimetry uncovers unexpected behavior and makes any scalability issues visible and quantifiable. It also helps to identify issues related to heat and mass transfer or mixing, and allows the determination of the correct temperature, stirring, or dosing profile of a given reaction or process. The information obtained is subsequently used to evaluate the risk, scalability, and criticality of a process.

Reaction calorimetry data is used to characterize, optimize and understand process parameters in a controlled, accurate, and reproducible environment, and to enable safe scale-up and transfer into manufacturing.

What is heat flow calorimetry?

what is heat flow calorimetry

what is heat flow calorimetry

Heat flow calorimetry is the simplest and most robust method to determine the heat released by a chemical reaction or physical process, and it is supported by all METTLER TOLEDO reaction calorimetry workstations. Heat flow calorimetry is highly sensitive and applicable under most conditions, and it offers excellent repeatability.

The heat flow calorimetry principle is based on the measurement of the temperature difference across the reactor wall, which is then converted into a heat flow by means of the calibration factor.

The calibration factor depends on the thermal conductivity and thickness of the reactor wall, the thermal resistance of the reaction mass film, the thermal resistance of the oil film, and the heat exchange area, and it is determined by means of an electrical heater.

The method of heat flow calorimetry is applicable on both small and large scales and is the basis for all chemical process development projects, process scale-up, and chemical process safety investigations.

What is the value of reaction calorimetry?

reaction calorimetry graph

Reaction calorimeters allow the efficient and safe development of processes at scale.

As a reaction is scaled from lab to plant, scalability problems may suddenly emerge for various reasons. In the worst case, unidentified reaction risks may lead to a runaway reaction followed by an explosion. The causes of thermal incidents are often attributed to:

  • Lack of understanding of the chemistry or the thermochemistry of a process
  • Inability to remove heat
  • Bad or poorly understood mixing behavior
  • Human factors

Incidents can be avoided by determining the relevant data at lab scale. The lab work is performed under process-like conditions using reaction calorimeters so that the results can be directly applied to larger-scale operations.

Reaction calorimetry provides a high level of process understanding so that the necessary procedures can be performed routinely, robustly, and to the required quality standards.

How can you obtain accurate and precise calorimetric data under any conditions?

Accurate and precise heat flow data is essential for transitioning from lab to plant. A high-performance heating and cooling system combined with a sensitive temperature measurement and control system is a prerequisite to obtaining accurate and precise heat information about a chemical process. This includes details about the heat of the reaction, the total heat flow balance, the mass and heat transfer, and the specific heat of the reaction mass.

The total heat flow balance of a chemical process itself includes a variety of thermal effects, such as the accumulation of heat, heat exchange due to reactant or solvent additions, heat due to changing viscosity, heat loss, etc.

For reactions that are run under changing temperature conditions, heat accumulation becomes an important factor in the calculation of the heat of the reaction (heat released as a function of time).

METTLER TOLEDO reaction calorimeters and iControl software suite use sophisticated calculation algorithms. These take into account the dynamic behavior of the reactor wall, the heat capacities of the vessel, and the reactor inserts – providing calorimetric data of maximum accuracy and precision.

What is heat of reaction?

The heat of reaction, or reaction enthalpy, is the energy that is released or absorbed during a chemical reaction. When reactants are transformed into products, it describes how the energy content changes. While there are endothermic (heat absorbing) and exothermic (heat releasing) reactions, the majority of reactions carried out in the chemical and pharmaceutical sectors are exothermic. The heat of reaction is one of the thermodynamic characteristics that is utilized in chemical research, scale-up, and safety to scale processes from the lab scale to production, among other things.

Learn more about heat of reaction and reaction enthalpy.

Can I connect my reaction calorimeter to third party accessories?

Yes! Extend your reaction calorimeter for automated control and data capture of third-party devices including sensors, dosing, and sampling solutions with the Easy Control Box (ECB) accessory (purchased separately).

ECB provides dosing control capabilities and easily connects commercially available pumps and balances for automated pre-programmed gravimetric or volumetric dosing.​ The accessory has plug-and-play measure functionality with SmartConnect Technology Sensors. Control elements are automatically recognized making the reactor system configuration a simple task.​ 

Learn more about Easy Control Box (ECB).

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