Glycothermal Synthesis and Catalytic Properties of Nanosized Zn1-xCoxAl2O4 (x=0, 0.5, 1.0) Spinels in Phenol Methylation

Zn1-xCoxAl2O4 (x = 0, 0.5, 1.0) spinels were synthesised under microwave-assisted solvothermal conditions using 1,4-butanediol as reaction medium. The results of XRD and HRTEM have indicated nanocrystallinity of prepared materials (average crystallite size in the range 6-16 nm), and N-2 adsorption-desorption measurements have revealed high feature of their surface area and mesoporous nature. Acid-base properties of prepared materials were determined using TPD-NH3 method and cyclohexanol test. All studied spinels that underwent examination were active in phenol methylation but Co-substituted zinc aluminate (Zn0.5Co0.5Al2O4) was found to be the most efficient in the selective formation of ortho-methylated products. It could be ascribed to its dominant basic character and the presence of weak and strong acid centres, and the highest surface area as well.