Synthesis of Ibuprofen

This example illustrates the reaction kinetics of complex chemical reactions occurring in a perfectly stirred tank reactor.

The homogeneous catalysis of 1-(4-isobutylphenyl) ethanol into the anti-inflammatory drug, ibuprofen, is modeled. The model determines concentrations of reactants, intermediates, and products as a function of time for the chemical reaction mechanism.

The model focuses on the use of the Reaction Engineering Lab for a kinetics investigation. You easily enter chemical reaction formulas from the keyboard, then the Reaction Engineering Lab automatically generates rate expressions and material balances. It solves the equations, and you postprocess results directly in the graphical user interface.

We investigate two kinetic paths:

1. A reaction path for forming Ibuprofen
2. A reaction path where Ibuprofen is allowed to additionally react reversibly with an alcohol to form an ester.

We conclude that the reaction runs to completion after 2 hours of operation in Case 1, whereas it takes 12 hours of operation in Case 2. The simulation takes less than one second on a typical PC.

Compression Ignition of Methane

Homogeneous Charge Compression Ignition (HCCI) engines are being considered as an alternative to traditional spark- and compression-ignition engines. As the name implies, a homogeneous fuel/oxidant mixture is auto-ignited by compression with simultaneous combustion occurring throughout the cylinder volume.

One of the challenges of these types of engines is to control the timing of the fuel ignition.

This model solves the mass and energy balances describing the detailed combustion of methane in a variable-volume system. Since the reaction mechanism is very large, the data needed in the model is imported from CHEMKIN Kinetics and Thermodynamic input files.

Degradation of DNA in Plasma

In gene therapy, plasmid DNA (pDNA) can express desired proteins in the human body. A major issue in gene therapy consequently involves the transport of pDNA to target sites and the conversion between different forms of this species. Furthermore, the pDNA-forms interconvert and degrade with time.

This example illustrates the kinetic analysis of pDNA degradation. You will build a kinetic model where the super coiled form of pDNA converts to the open circular form and subsequently to the linear form. The linear form of pDNA finally decomposes into a number of linear fragments. The material balances are subsequently solved under isothermal conditions.

You will then compare simulation results with experimental data in order to calibrate and validate the model.

Selective Reduction of Nitric Oxide

The removal of pollutants from combustion processes is currently a very important issue for the environment. One such pollutant is Nitric Oxide, found in the exhaust of gasoline and diesel engines.

This model treats the selective catalytic reduction of Nitric Oxide in an exhaust gas stream. The reaction takes place on the catalytic surface of a monolith reactor.

A first simulation models the monolith channel as a plug-flow reactor. A second simulation takes the actual channel geometry into account and solves the coupled mass and momentum balance equations, considering free flow in the channel, and porous media flow in the washcoat.

Chemical Vapor Deposition of GaAs

Chemical Vapor Deposition (CVD) is an important process for the electronics industry that often uses it to grow thin layers onto semi-conductor surfaces. A thin film is grown on a substrate by allowing molecules and molecular fragments to adsorb and react on a surface.
Combining detailed chemical reaction kinetics with transport models of a CVD reactor allows for realistic modeling of the deposition process.

Firstly, you will compare a reduced reaction scheme to the full scheme in the COMSOL Reaction Engineering Lab. In this tool, it is easy to study different models by activating and deactivating reactions.

Then, you will export the reduced scheme described in the Reaction Engineering Lab to the Chemical Engineering Module in COMSOL Multiphysics for the simulation of the complex reaction/transport mechanisms in a detailed reactor geometry.