Ni-Al mixed oxides as catalysts in the reactions of conversion of the higher alkanes

Abstract

© SGEM2018. In this study, investigation of the composition, structure and catalytic activity of the catalyst support based on Ni-Al mixed oxides was carried out. The possibility of controlling structural and acid-base properties of the layered double hydroxides (LDH) by varying the ratio of M2+/M3+ metal cations determines its use as catalyst support. Besides varying of anions in the interlayer space allows to regulate catalytic system activity in the reaction medium. The Ni-Al LDH support was prepared by coprecipitation method followed by conversion to Ni-Al mixed oxide in the reaction medium. According to the X-ray diffraction analysis, it was shown that the Ni-Al-based mixed oxide obtained with a specific surface area of 158 m2/g contains nickel oxide with a reduced lattice parameter related with the replacement of part of Ni2+ cations with Al3+, phase of mixed oxides of variable composition and amorphous phase. The replacement of Ni2+ by Al3+ in nickel positions is 16%. The crystallite size of the obtained oxide phases is 4 nm. The catalytic activity of Ni-Al mixed oxide was determined in the reactions of the conversion of higher alkanes of the C11-C22 composition, taken in equal proportions, at a temperature of 500°C and a feed to catalyst ratio of 30. According to the chromatographic analysis, alkanes and isoalkanes of composition C7-C14 were formed as catalytic products. Unsaturated compounds in the reaction products were revealed by IR spectroscopy method; the iodine value was 0.172.