The two catalysts were selected based on their distinctly different
textural and surface properties. More specifically, the catalysts
tested were an acidic commercial equilibrium ZSM-5 zeolite
diluted with silica-alumina (containing 30 wt.% crystalline zeolite)
and a basic magnesium oxide (MgO), which was produced
industrially via calcination of natural magnesite at temperatures
between 700 and 1100 C (Grecian Magnesite S.A.). The ZSM-5 based catalyst had a surface area of 127 m2/g (determined by the
BET analysis of the N2 adsorption data at 77 K), total number of
acid sites 0.14 mmoles NH3/g (determined by temperature programmed
desorption of ammonia-TPD/NH3 experiments), and
Brönsted to Lewis acid sites ratio of 1.8 (determined by FT-IR
spectroscopy coupled with in situ adsorption of pyridine)
(Iliopoulou et al., 2012, 2014). The MgO catalyst had a surface
area of 62 m2/g and exhibited negligible acidity (i.e.