A study has been carried out by Chin et al. [37]. They produced
methyl ester from PFAD using a sulfonated sugar cane bagasse acid
catalyst. At the temperature of 170 C, methanol content of 20:1,
11.5 wt.% of the catalyst and 30 min reaction time, the activity of the
catalyst dropped 15% after 5 reaction cycles from 80% to 65% of the
methyl ester content.