Kinetic study of alkylation of benzene with ethanol over bimetallic modified HZSM-5 zeolite catalyst and effects of percentage metal loading

Abstract

According to International Zeolite Association (2014), until now, there are 218 zeolite framework type codes that have been discovered. Worldwide consumption of zeolites (natural and synthetic) is estimated to be about 5 million tons per year. The annual market for synthetic zeolites and molecular sieves was developed vastly to 1,800,000 ton worldwide in 2008. 3 Alkylation of benzene is a vital reaction in the petrochemical industry. Benzene alkylation technologies offer improvements in octane number and gasoline volume. Ethylbenzene, diethylbenzene, toluene, and xylenes are important raw materials for many intermediates of commodity petrochemicals and valuable fine chemicals. Ethylbenzene (EB), which is one of the most important products used as the chemical intermediate, is the main feedstock for the synthesis of styrene which is then polymerized into polystyrene, a common plastic material. 4 Ethylbenzene is also used in the chemical industry in the manufacture of acetophenone, cellulose acetate, diethylbenzene (DEB), ethyl anthraquinone, ethylbenzene sulfonic acids, propylene oxide, and α-methylbenzyl alcohol. 5 Additionally it is used as a solvent, a constituent of asphalt and of naphtha, and in fuels. Ethylbenzene and xylene mixtures are used in the paint industry and in the production of pesticides in agriculture. 5

Micro‐Mesoporous Hierarchical Beta Zeolite and its Catalytic Application in Acetic Acid Benzylation

“…The result from the NH 3 ‐TPD is supported by a comprehensive analysis of X‐ray diffraction (XRD), low‐angle X‐ray diffraction (LAXRD), N 2 sorption investigation, and chemical titration (Table S1). The Beta‐0.1 N NaOH specimen displays a remarkable mesoporous surface area (S meso =158 m 2 g −1 ) and a diverse distribution of acid sites, that are primarily accountable for the alkylation reactions [69] . After the base treatment the catalytic efficiency of material is enhanced, which is represented by increase in the peak for the strong acid sites.…”

“…The Beta-0.1 N NaOH specimen displays a remarkable mesoporous surface area (S meso = 158 m 2 g À 1 ) and a diverse distribution of acid sites, that are primarily accountable for the alkylation reactions. [69] After the base treatment the catalytic efficiency of material is enhanced, which is represented by increase in the peak for the strong acid sites. The low-temperature peak is indicative of desorption of ammonia from Lewis acid sites with weak acidity, whereas the high-temperature peak is correlated with Brönsted acid sites that exhibit greater acidity.…”

Hierarchical Nanospherical ZSM-5 Nanosheets with Uniform Al Distribution for Alkylation of Benzene with Ethanol

“…Subsequently, an ethoxy cation attacks benzene molecule to form protonated ethylbenzene. Ethylbenzene is eventually obtained when a protonated ethylbenzene returns a proton to the zeolite surface . In order to avoid the production of diethylbenzene and higher hydrocarbons via the secondary reactions, we fixed the ratio of benzene to ethanol at 2:1.…”

“…Ethylbenzene is eventually obtained when a protonated ethylbenzene returns a proton to the zeolite surface. 70 In order to avoid the production of diethylbenzene and higher hydrocarbons via the secondary reactions, we fixed the ratio of benzene to ethanol at 2:1. It was reported that with a lower volume fraction of benzene, there is a higher possibility of diethylbenzene formation due to a higher alkylation activity of ethylbenzene caused by the positive inductive effect of ethyl group and eventually the catalyst can be easily deactivated.…”