A solvent extraction method to study the location and concentration of coke formed on zeolite catalysts Original Research Article

The location and composition of the coke formed over H-ZSM-5 zeolites during the cracking of hexadecane at 350°C and at 20 atmospheres was studied. A solvent extraction technique using two different solvents located the coke either on the external surface or within the pores of the zeolite and GC-MS analysis characterised the soluble coke. Coke was also examined using 13C MAS NMR and high resolution TEM. Substituted benzenes were identified as the major precursors to coke formation, and the external coke had a graphitic structure. The contact time was shown to affect only the rate of formation but not the composition of the coke.