Applications of the Micro Reaction Calorimeter
Power-compensation method. Versatility Automated sample addition, repeated or timed. Wide temperature range Pressure measurement Stirring Highly sensitive Unattended operation Small footprint Moderate cost / benefits
The Micro Reaction Calorimeter has a wide range of potential applications. Any reaction where heat is produced or consumed (endo or exothermic) will be suitable for study with this technique. The quantification of heats of this kind will be important in: Process safety Process optimisation Process development Deviation studies Catalyst Screening Material compatibility Inter-material Reactivity Stability and storage testing Reaction Screening Kinetic analysis and development Binding studies Environmental studies Shelf Life Material Curing
The Micro Reaction Calorimeter can operate in number of different modes. 1. Incremental titration (Titration Calorimetry) 2. Continuous addition (Reaction Calorimetry) 3. Single shot addition (Safety Calorimetry) 4. Calibration, heater pulse (Specific Heat Measurement) 5. Non addition - stability and storage (Isothermal Calorimetry) 6. Temperature ramping (Scanning Calorimetry) 7. Pressure measurement (Safety Calorimetry) The integrated addition syringe means that all liquid-liquid reactions can be conducted with walk-away operation minimising the users time requirement. But the instrument is not restricted to liquids.
Thermodynamic measurement Heats of reaction, mixing Kinetic development Process development and optimisation Catalyst development Academic research Teaching Other applications Measurement of equilibrium constants Determination of state changes
Reaction Calorimetry / Safety Example Acetic anhydride hydrolysis 5 µl of Acetic Anhydride into water
This application shows how quickly the Micro Reaction Calorimeter can obtain reaction heats for slow processes. Although this reaction takes almost an hour to complete the measurement of the heat takes very little additional time. Note the rapid response and also the initial endothermic contribution this is the heat of mixing! The results compare with the published values of 58.6 kj/mol Volume Added /µl 5.0 Mass added /g 0.0054 Formula Mass 102.09 Amount reacted /mmol 0.0529 Peak Area / J 3.089 Heat of reaction /(kj/mol) -58.4
Advantages of Micro Reaction Calorimetry for Process Safety Measurement The small volume of the system reduces cost, time and waste Process deviation studies (considering overcharging, over temperature and mal-operation) are therefore quick and easy Total saving can be several days work and litres of reagents/waste
Typical compatibility study 5 µl of Isopropanol into water
Typical reaction hazards study Reduction of strontium oxide by organic acid Highly exothermic 103kJ/mol Shows the µrc s ability to measure highly exothermic systems and the reactions between solids and liquids
Process optimisation / catalyst study Data shows the kinetics of the reaction: Decreasing maximum heat shows the decrease in reactant concentration whilst the overall integral remains constant 4 consecutive injections of 10µl anhydride
Reaction calorimetry can easily be used for kinetic analysis. Low Volume systems improve the ability to collect better kinetic data Power compensation method gives rapid response improves the ability to get quality kinetic data Heat is directly related to reaction conversion and therefore to reagent concentration. These experiments save a lot of time over conventional kinetic techniques.
10ml injections of anhydride were added to thiophene. Analysis of the data produced: H= H=-29kJ/mol rate constant of 3.9e -04 (kmol/m 3 ) -1.00 /s. Heat production rate, kj/kg/min 3.0 2.5 2.0 1.5 1.0 0.5 1.00 /s. 0.0 0 25 50 75 100 125 150 Time, min Points measured data Line kinetic fitting
Binding study (Supramolecular, Host-Guest Chemistry) Binding of 18-Crown-6 ether to Barium ions Decrease of reaction heat with increasing 18-Crown-6 shows the binding equilibrium
Binding study (Supramolecular, Host-Guest Chemistry) integral of the data, changing with amount added Binding equilibrium constant, heat of binding and stoichiometry all can be obtained easily from these data
Stability Testing, High Energy Materials - isothermal calorimetry The high thermal stability of the system paired with excellent heat detection makes this ideal for determination of time induced processes.