Influence of reaction parameters on glycerol dehydration over HZSM-5 catalyst
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Influence of reaction parameters on glycerol dehydration over HZSM‑5 catalyst Juliana Oliveira Fernandes1 · Thaís Martins Neves1 · Edilene Deise da Silva2 · Cezar Augusto da Rosa1 · Vanessa Bongalhardo Mortola1 Received: 3 June 2020 / Accepted: 20 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract HZSM-5 with Si/Al ratio of 25 has been synthesized and applied as a catalyst to the gas-phase dehydration of glycerol. Despite the high conversion and selectivity to acrolein achieved by this zeolite, its deactivation is still an issue. Therefore, successful application of this zeolite depends on deep understanding of how operating conditions affect its behavior. This study aims to investigate how distinct reaction conditions influence conversion and selectivity over time of HZSM-5 with Si/ Al ratio of 25. In order to accomplish these objectives, HZSM-5 was synthesized and characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption, temperature-programmed desorption of NH3 and thermogravimetric analysis. The catalyst was tested under different conditions of O2 concentration (0, 10, 15 and 20 V%), temperature (300, 325 and 350 °C), glycerol aqueous solution concentration (10, 15 and 20 wt%) and spatial velocities (1091, 1227 and 1363 h−1). Results showed that the different conditions under evaluation played a key role in the catalyst performance and lifetime. Under the range studied, increasing O2 concentration and temperature, and decreasing glycerol feeding ratio and spatial velocity had positive effect on glycerol conversion. Selection of proper operating conditions enabled the achievement of high glycerol conversion (above 93%) and high selectivity to acrolein (around 79% of the liquid products) over 15 h of reaction. Keywords HZSM-5 · Glycerol dehydration · Reaction parameters · Proper operating conditions · Acrolein Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1114 4-020-01874-w) contains supplementary material, which is available to authorized users. * Vanessa Bongalhardo Mortola [email protected] 1
School of Chemistry and Food Science, Federal University of Rio Grande, Av. Italia km 8, Carreiros, Rio Grande, RS 96203‑900, Brazil
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Research Center on Advanced Materials and Energy, Federal University of São Carlos, Rodovia Washington Luiz, km 235 –SP310, São Carlos, SP 13565‑905, Brazil
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Reaction Kinetics, Mechanisms and Catalysis
Introduction Glycerol conversion into high value-added products can be performed through distinct chemical routes [1–6]. Catalytic gas-phase dehydration of this polyol is a reaction conducted at mild pressure and temperature to yield certain products, such as acrolein, acetaldehyde and acetol [7, 8]. Acrolein is the simplest unsaturated aldehyde which has been commonly used as a feedstock in the chemical industry to produce acrylic acid, acrylic acid esters, superabsorber polymers and detergents [9, 10]. Nevertheless, high yield of acrolein through glycerol d
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