High-efficiency catalytic performance over mesoporous Ni/beta zeolite for the synthesis of quinoline from glycerol and aniline

Abstract

A green route for the vapor-phase synthesis of quinoline from glycerol and aniline was developed in this work, employing Ni/mesoporous beta zeolite (denoted as Ni/Hβ-At) as a catalyst. The mesoporous beta zeolite was prepared by alkaline treatment. Various influencing factors were systematically investigated. Both mesopores and the type of acid sites of the catalyst played important functions in catalytic activity for the synthesis of quinoline. Mesopores facilitated the transport of bulky products from internal surface of the catalyst. Meanwhile, weak Brønsted acid sites favored the dehydration of glycerol to acrolein and the existence of Lewis acid sites could accelerate the formation of quinoline. The Ni/Hβ-At catalyst exhibited the highest catalytic activity; and as high as a 71.4% yield of quinoline was obtained under the optimized reaction conditions. An enhanced ability of anti-deactivation was also displayed, due to the existence of mesopores on the Ni/Hβ-At catalyst facilitating the transport of bulky products and restraining the deposition of the coke. Meanwhile, it was found that the coke was main reason leading to catalyst deactivation and its performance was basically regenerated. The catalytic properties were slightly lower after 3 reaction–regeneration cycles. Finally, a feasible reaction pathway was proposed on the basis of the various products.