Fig. 3. Concentration of eucalyptol and its degradation products versus reaction time. ‘‘Original’’ in the x-axis means the mixture of eucalyptol with the methanol/water.
‘‘Mix’’ means the mixture of eucalyptol, methanol/water, and Amberlyst 70. ‘‘0 min’’ means that the temperature just reached the required reaction temperature.
Experimental conditions: T = 170 C; catalyst loading: 15 wt.%; methanol/water mass ratio: 8.