Acid catalysis

Strong acids catalyze the hydrolysis and transesterification of esters, e.g. for processing fats into biodiesel.

[3] A particularly large scale application is alkylation, e.g., the combination of benzene and ethylene to give ethylbenzene.

This kind of catalysis is common for strong acids in polar solvents, such as water.

For example, in an aqueous buffer solution the reaction rate for reactants R depends on the pH of the system but not on the concentrations of different acids.

This type of chemical kinetics is observed when reactant R1 is in a fast equilibrium with its conjugate acid R1H+ which proceeds to react slowly with R2 to the reaction product; for example, in the acid catalysed aldol reaction.

In general acid catalysis all species capable of donating protons contribute to reaction rate acceleration.

When reactions are conducted in nonpolar media, this kind of catalysis is important because the acid is often not ionized.