Laboratory of Engineering Thermodynamics (LTD)

DFG Reinhart Koselleck Project

Press release (german)

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Abstract

In classical process engineering, an excellent status has been reached in the field of quantitative modeling and simulation. Experiments are often only necessary for the specific validation of model predictions. The essential basis for this are thermodynamic material data models, which are highly developed for simple molecules, but also for polymers. This is different for complex molecules such as proteins, active ingredients and many fine chemicals, i.e. for substance classes that will decisively shape process engineering in the future. Here, the thermodynamic substance data models required for physicochemical modeling of the process engineering processes are largely lacking. In the present project, a way into this field is to be paved. The approach of molecular modeling and simulation with force field methods will be pursued. This approach is already successfully used for qualitative studies of complex molecules as well as for quantitative studies of systems with simple molecules. In the project, its extension to the quantitative description of thermodynamic material data of complex molecules is aimed at. The aim is to provide a methodological kit and associated model building blocks and tools which, similar to the well-known UNIFAC group contribution method in classical process engineering, can be used in the future to successfully handle process engineering tasks with complex molecules.

Target

Molecular simulations with force field methods are successfully applied in various fields today. A rough structure is shown in Figure 1. In the field of qualitative molecular modeling and simulation of simple molecules (quadrant I) there is hardly any need for research. Qualitative molecular simulation of complex molecules (quadrant II) is nowadays mainly carried out in the field of biochemistry. Neither the models nor the simulation tools used in this field meet the quantitative requirements of process engineering. In the field of quantitative molecular modeling and simulation of systems with simple molecules (quadrant III), considerable progress has been made in recent years. Thermodynamic properties of simple molecules can now be predicted with molecular simulations in many cases with an accuracy sufficient for process engineering applications. In contrast to phenomenological approaches, all thermodynamic material data of interest are covered: thermal and caloric state variables, entropic state variables such as the chemical potential, transport variables, structural variables such as pair distribution functions, etc. Due to the consistent separation of the different types of intermolecular interactions, (repulsion, dispersion, polarity etc.) and the fact that the approach consistently describes the complex relationships between the energetic interactions and the structure of the fluid, a high predictive capability is achieved. The aim of the present project is to advance from quadrants II and III to quadrant IV and pave the way for quantitative molecular simulations of complex molecules.

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