The effect of hierarchical pore architecture on one-step catalytic aromatization of glycerol: Reaction routes and catalytic performances

One-step aromatization of glycerol to value-added aromatics is a very promising way not only owing to the growing byproduct of glycerol in biodiesel manufacturing but also due to the imperious demands to provide a sustainable route for aromatics production to alleviate the dependence on fossil fuels. Different hierarchical HZSM-5 catalysts with diverse sizes of intramesoporosity and similar size of microporosity are prepared by desilication with different alkali. The occurrence of deoxygenation and dehydration reactions among the GTA process brought about a noticeable drop in the oxygen content of the organic products and as a consequence, resulted in a superior quality in liquid products, in which aromatics, such as benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, et al., were the major components. Liquid route during the GTA reaction was suppressed while the gas route was enhanced over the desilicated HZSM-5 samples, leading to the increment of BTX light aromatics yields and reduction of the heavier aromatics yields (trimethylbenzene, tetramethylbenzene). It was found that smaller intramesopores (3-5 nm) together with well-preservation of parent HZSM-5 microporosity exhibited better shape-selective BTX yields and slower carbon deposition rate during the GTA procedure than larger ones (6-16 nm). (C) 2017 Elsevier B.V. All rights reserved.