One-pot synthesis of 2-ethylanthraquinone from phthalic anhydride and ethylbenzene over a Sc-modified Hβ catalyst

2-Ethylanthraquinone is frequently used for producing bulk consuming chemicals. However, the synthesis of 2-ethylanthraquinone is still restricted by expensive raw materials, complex preparation process and poor-cycling catalyst. Herein, a one-pot method is developed to synthesize 2-ethylanthraquinone using phthalic anhydride and ethylbenzene as feedstock by combination of acylation and dehydration over a Sc-modified Hβ catalyst. Sc-modified Hβ was prepared via impregnation and catalyzed conversion of phthalic anhydride about 58.8% and 2-ethylanthraquinone selectivity up to 78.5% which is better than the results by other metals-modified Hβ zeolites. By adjusting Sc loading amount in Hβ, more acids are created especially strong Lewis acid and an appropriate synergistic effect of Lewis/Bronsted acids is obtained for cascade reactions of acylation and dehydration. Then, the reaction conditions were investigated and the catalyst can be reused in 4 runs. This work provides a green and simple way for 2-ethylanthraquinone synthesis.