Application of Response Surface Methodology for Ethanol Conversion into Hydrocarbons Using ZSM-5 Zeolites

Abstract

The ethanol conversion into hydrocarbons (light olefins and aromatics) using alkali-treated HZSM-5 with different SiO2/Al2O3 ratios (23, 38, and 53) zeolites was evaluated. The desilicated SAR 38 zeolite exhibited significant growth on the external surface area (61–212 m2/g) and the mesopore volume (0.07–0.37 cm3/g) without significate reduction on XRD crystallinity (93%). All catalysts were active on the ethanol conversion into hydrocarbons. At the same set of variables, the alkali-treated HZSM-5 zeolites showed a better conversion and a high selectivity to C4–C9 hydrocarbons when compared to the parent microporous zeolites. Only the parent HZSM-5 zeolite (SAR 53) was chosen for the statistical study using the standard response surface methodology in combination with the central composite design. It was found that maximum BTEX (benzene, toluene, ethylbenzene, and xylenes) and minimum ethylene production were reached for the following conditions: temperature 450 °C, pressure 20 bar, and WHSV (weight hourly space velocity) 5 h−1.

Bioethanol Upgrading to Renewable Monomers Using Hierarchical Zeolites: Catalyst Preparation, Characterization, and Catalytic Studies

“…There are two main methods, desilication and dealumination, in which the removal of Si and Al from the zeolite frameworks was obtained, respectively. For example, the desilication of ZSM-5 zeolite was performed by mixing the NaOH solution with the parent ZSM-5 under vigorous stirring at 65 • C in a polypropylene bottle [34]. Dealumination has been achieved by an acid treatment.…”

“…Textural properties and pore architecture of hierarchical zeolite catalysts are normally investigated by the gas adsorption-desorption technique and transmission electron microscopy (TEM), respectively. For example, the desilicated ZSM-5 zeolites that have different Si/Al ratios (20 and 50) were characterized with the N 2 -sorption technique to investigate the textural properties to compare the different aspects between the ones before and after the alkaline treatment [34]. The N 2 sorption isotherms are shown in Figure 4.…”

“…Moreover, the higher weight hourly space velocity (WHSV) affected the higher ethylene production. Subsequently, the catalytic activities of alkali-treated HZSM-5 zeolites with various Si/Al ratios of 11.5, 19, and 26.5 were evaluated by the catalytic reaction of ethanol transformation into hydrocarbons (aromatics and light olefins) [34]. Under similar experimental conditions, the alkali-treated HZSM-5 catalysts exhibited higher ethanol conversion and high selectivity of C 4 to C 9 hydrocarbons compared to the parent catalysts.…”

Desilicated ZSM‐5 Catalysts: Properties and Ethanol to Aromatics (ETA) Performance

“…The low yield of alkanes in the gaseous fraction indicates a similarly low yield of stoichiometrically formed aromatics in a study applying an even higher overpressure. [22] Nevertheless, a higher selectivity to C 4 -C 9 hydrocarbons, compared with microporous ZSM-5, was noted after desilication. For dealuminated and base-washed ZSM-5 catalysts applied in the ethanol conversion, it was found that the location and thus shape-selectivity of BAS sites, causing different reaction speeds, in combination with the speed of transport determine how many aromatics are formed and how fast ZSM-5 catalysts deactivate.…”

The Steric Effect in Green Benzylation of Arenes with Benzyl Alcohol Catalyzed by Hierarchical H-beta Zeolite

“…However, in the research for better reactivity and no etherification to form dibenzyl ether (DBE), to decrease selectivity [5], extensive works have already been published using BzCl [6][7][8][9][10][11]. It is still necessary to gain more insight on understanding catalytic reaction mechanisms with the more challenging BzOH as benzyl reagent because as one of the enduring research themes in chemistry [12][13][14][15][16][17][18], developing green catalytic process is beneficial to build an ecofriendly and sustainable economy.…”