Liquid phase hydrogenation of adiponitrile over acid-activated sepiolite supported K–La–Ni trimetallic catalysts

Abstract

Acid-activated sepiolite (ASEP) supported K–La–Ni trimetallic catalysts were prepared and tested in the liquid phase hydrogenation of adiponitrile (ADN). The sepiolite was treated with dilute hydrochloric acid solution to obtain ASEP, ASEP supported K–La–Ni trimetallic catalysts were prepared by the incipient impregnation method and characterized by nitrogen adsorption–desorption, temperature programmed reduction, hydrogen chemisorption, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and energy dispersive X-ray. It was revealed that potassium could inhibit the formation of the 1-azacycloheptane by-product by neutralizing some acid sites on the catalyst, and the potassium and lanthanum could efficiently reduce nickel particles size and improve its dispersion. Sepiolite treated with hydrochloric acid increases the number of silanol groups (Si–OH) on the sepiolite surface, which is helpful to nickel particles adsorption and dispersion. ASEP supported K–La–Ni trimetallic catalysts (K–La–Ni/ASEP) present better catalytic performance under mild reaction conditions of 373 K and 2.0 MPa, the ADN conversion reaches to 90.03 %, the selectivity to 6-aminocapronitrile and hexamethylenediamine is up to 90.22 %.