Catalytic properties of the framework-structured zirconium-containing phosphates in ethanol conversion

• Published in: Research on chemical intermediates 2021-09, Vol.47 (9), p.3645-3659
• Main Authors: Mayorov, Pavel, Asabina, Elena, Zhukova, Anna, Osaulenko, Diana, Pet’kov, Vladimir, Lavrenov, Dmitry, Kovalskii, Andrey, Fionov, Alexander
• Format: Article
• Language: English
• Subjects: Acetaldehyde; Aldehydes; Aliphatic alcohols; Alkenes; Catalysis; Catalysts; Catalytic converters; Chemical compounds; Chemical synthesis; Chemistry; Chemistry and Materials Science; Composition; Conversion; Crystallization; Diethyl ether; Ethanol; Ethers; Inorganic Chemistry; Ketones; Lewis acid; Phase stability; Phosphates; Physical Chemistry; Sodium zirconium phosphate; Symmetry; Transition metals
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-021-04488-6

Aliphatic alcohols C1–C4 can serve as raw material for the production of essential organic products, such as olefins, aldehydes, ketones and ethers. For the development of catalysts of alcohols’ conversion, the authors considered two families of framework phosphate compounds with significant chemical, thermal and phase stability: NaZr 2 (PO 4 ) 3 (NZP/NASICON) and Sc 2 (WO 4 ) 3 (SW). Variation in the composition of zirconium-containing NZP- and SW-complex phosphates allows one to vary the number and strength of Lewis acid centers and incorporate oxidative-reducing centers (such as d-transition metals) into the structure. The phosphates M 0.5+ x Ni x Zr 2 −  x (PO 4 ) 3 (where M are Mn and Ca) were studied in the reactions of ethanol conversion. From the results of complex investigation, the compounds with M–Mn ( x  = 0, 0.3 and 0.5) were crystallized in the SW-type (monoclinic symmetry), while the phosphates with M–Ca ( x  = 0, 0.2 and 0.4) were characterized as the NZP-structured compounds (trigonal symmetry). The surface areas and pore volumes of synthesized catalysts varied, with different compositions, from 14 to 32 m 2 /g and 0.03 to 0.12 mL/g, respectively. From the catalytic experiments, the main direction of conversion on all the studied catalysts was ethanol dehydrogenization with acetaldehyde formation. The other conversion products—diethyl ether and ethylene—were produced with small yields. Based on the results obtained, the NZP-sample Ca 0.5 Zr 2 (PO 4 ) 3 can be considered as a selective catalyst for producing acetaldehyde at 400 °C with a yield of 55% from its theoretical amount.