Solid-phase organic synthesis catalysed

The increase in the rate of reactions catalysed by quaternary ammonium salts is often proportional to the concentration of the catalyst used. When I started to collect data for their use in organic synthesis, it rapidly became obvious that it was difficult to make a clear distinction between purely catalytic reactions and those using stoichiometric amounts of the ammonium salt this was because the practical techniques often varied (e.g., liquidiliquid two-phase reactions vs liquid solid two-phase reactions). Consequently, I have presented a general practical overview of the use quaternary ammonium salts, categorised according to specific bond formations or reaction types. I have tried to be as comprehensive as possible, but in order to keep the text concise, some abstruse experimental variations have been omitted, as has a complete citation of the patent literature. 

There are indeed significant fundamental and practical differences between classical organic reactions (either stoichiometric or homogeneously catalysed ones) and those catalysed by solids and especially zeolites (Table 2.1). It is also the case when one compares the relatively simple transformations generally studied by the specialists in Heterogeneous Catalysis and the transformation of complex molecules involved in the synthesis of Fine Chemicals. The operating conditions are very different high temperature, gas phase, fixed bed reactors on the one hand low... 

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