Friedel-Crafts Alkylation of Phenanthrene with Ethanol to Alkyl-Phenanthrenes Over Modified Usy Catalyst

Abstract

Alkylation of PAHs is a promising approach to enhance their value while reducing carcinogenicity. In this study, alkylation of phenanthrene with ethanol over zeolites was conducted, experimental results indicated that alkyl-phenanthrenes containing three alkyl carbons (Phenanthrene-C3) were the main products. USY-2 zeolite modified by NaOH solution (0.75mol/L, 1.5 h and 90 °C) and Co2+ (9 wt%) was found to give the highest yield of 61.24 wt%. The selectivity to Phenanthrene-C3 is in the order of modified metal Cu (90.88%) >Zn>Fe>Ag>Co>La>Ba>USY-2>K>Cs>Ni (59.11%), while the conversion rates of Co (72.84%) >K>USY-2>Ag>Zn>Fe>Cu>La>Ba> Cs>Ni (8.42%), which is due to the smaller ionic radii impregnated metal ions can easily substitute into the zeolite lattice, while ions with larger ionic radii resulted in lower pore volume. In addition, the experimental results demonstrated that the loaded metal inhibited the increase in yield of alkyl-phenanthrene by alkali treatment, due to the plugging of the mesopores formed by etching.

Keywords: Phenanthrene, Friedel-Crafts alkylation, USY, Kinetic modeling, Metal ion radius