Molecular Systems Engineering


Leonhard, Kai © Copyright: Lehrstuhl fuer Technische Thermodynamik der RWTH Aachen


Kai Leonhard

Group Leader Molecular Systems Engineering


+49 241 80 98174



With model-based design of molecular systems, we can optimize processes and the processed materials at the same time. We develop novel methods and apply them in cooperation projects to

  • develop novel fuels from Biomass and CO2, which combust with very low emissions,
  • design solvents, reaction and separation media, mainly for the utilization of CO2 as a raw material,
  • produce polymers sustainably and to recycle them.

The ecologic and economic production of base chemicals is a major goal. We model the molecules together with the processes they appear in, e.g. for the purification of intermediates and for improving the quality of products of chemical reactors.

Molecular Thermodynamics is one foundation for our work. It is the basis for the development of models for physical and chemical properties based on molecular structures. It employs methods from quantum mechanics, statistical mechanics and classical thermodynamics. With such models, we can obtain desired properties without performing time-consuming experiments. We develop models for equilibrium properties and for chemical reactions since they are often important for the production and application of materials.

Design methods are the second foundation. Design methods allow us to identify optimal molecular structures based on the models described above and based on specified targets.

We contribute to the success of the following coordinated projects with our methods:

  • Cluster of Excellence „The Fuel Science Center“
    (Ab initio Combustion Kinetics and ChemTraYzer)
  • SFB 985 „Functional Microgels and Microgel Systems“
    (Microgel Synthesis: Kinetics, Particle Formation and Reactor Modelling)
  • BMBF-Project “Carbon2Polymers”

If you are a student and are interested in our work, you can learn more about our methods in the lectures Applied Molecular Thermodynamics, Applied Quantum Chemistry for Engineers and Combustion Chemistry.


Current Projects

Ab initio combustion kinetics
Accurate Thermochemistry and Kinetics of Molecules with Coupled Motions
Development of a predictive equation of state
Integrated molecular and process design based on fully predictive methods
Microgel synthesis: Kinetics, particle formation and reactor modelling

Completed Projects

Analytical property prediction models for complex fluids
AutoCheMo - Automatic Generation of Chemical Models
Chemical use of carbon dioxide as C1 building block in conjunction with use of predominantly regenerative energy
Design methods for QM-based property models
Kinetics of Ionic Liquids Synthesis: Design of Experiment and Process Optimization
Multiscale Simulation of Microgel Structure
Quantum mechanical Calculation of ideal gas properties
Reconstruction of the Microcanonical Rate Constant from Experimental Thermal Data
The role of non-Boltzmann-distributed products in gas phase kinetics
Thermal stability of ionic liquids on the molecular level