4. Alkylation processes in the presence of heterogeneous catalysts

The use of heterogeneous catalysts is the most suitable solution for reducing the risks inherent in the use of liquid catalysts and in particular HF. The aim is to provide an environmentally risk-free alternative at a cost comparable to HF and H ₂ SO ₄ processes.

Research into catalysts and associated technologies has come up against several major difficulties:

• the catalyst must be sufficiently acidic to enable it to operate at low temperatures (below 50°C), so as to minimize cracking reactions of the alkylates produced, as well as oligomerization reactions of the olefins. Both alkylation yield and alkylate quality (octane number) deteriorate as reaction temperature rises;

• the products of the...