The composition of ionic liquids is expressed as
the apparent AlCl3 mole fraction, N. Accordingly,
they are classified as basic, neutral or acidic liquids
where N is 0–0.5, 0.5 and 0.5–0.67, respectively. The
Pechmann condensation of phenols with ethyl acetoacetate
was carried out in N=0.33, 0.5 and 0.67
liquids. Positive results were obtained only in the case
of an acidic ionic liquid as expected. The liquid
corresponding to N=0.67 gave a maximum yield in
minimum time and hence was utilised for all the reactions.