The concept of SILP technology was originally based on ILs in catalysis. In these systems the mass transport into the ionic liquid phase can be rate limiting due to the high viscosity of the ionic liquids.

By dispersing the ILs on support materials these drawbacks can be circumvented. Furthermore, stable and easy to handle solid catalyst materials are obtained which can be used in fixed-bed reactors.

The SILP concept consists of the four major building blocks, namely the support, the ionic liquid, the catalyst and the reactants. For a given reaction the reactants are usually fixed. By choosing the appropriate combination of catalyst, ionic liquid and support novel SILP materials can be obtained having sometimes superior properties compared to conventional catalysts.

In the case where the support itself is catalytically active, coating of heterogeneous catalysts with ILs is another exciting part of SILP technology by which novel catalysts are obtained. The ionic liquid can act as a membrane material and facilitate transport to or from the active centre, thus influencing the overall selectivity.