Dehydration of 2-(4′-Ethylbenzoyl)-benzoic Acid to 2-Ethylanthraquinone over Hβ Zeolite Modified with Organic Acids

Hβ zeolite was modified with citric acid, tartaric acid, malic acid, propanedioic acid, lactic acid, acetic acid, and oxalic acid, respectively, and characterized by X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectrometer, nuclear magnetic resonance, and temperature programmed desorption. The catalytic performance of the samples in the dehydration of 2-(4′-ethylbenzoyl)-benzoic acid (BEA) to 2-ethylanthraquinone (2-EAQ) was studied. The results showed that Hβ maintained the BEA topological structure after being modified by organic acids, but their relative crystallinity and amount of acid groups decreased, and dealumination could be clearly observed after the modification. Hβ zeolites modified with citric acid, tartaric acid, malic acid, and propanedioic acid showed great catalytic performance in the dehydration reaction of BEA to 2-EAQ. The conversion of BEA and the selectivity to 2-EAQ were both up to 95.0%.