The CBSC can be deactivated by leaching of sulfonated species, formation of sul­fonic esters (Kang et al. 2013). Most usually there are five reasons behind catalyst deactivation, these are Sintering, Evaporation, Poisoning, Fouling, and Thermal
degradation often occurred by mechanical damage, high temperature, and corrosion by the reaction mixture. Hence study of leaching catalyst is important for the carbon-based catalysts. Since the functional groups of the carbon based sulfonated acid catalysts consisted of SO3H, COOH, OH, shows the leaching of SO3H and possibly COOH and OH into the reaction medium (Adrian 2012).