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

Shri Chand,Abdi Nemera Emana

doi:10.1080/2055074x.2016.1198545

Shri Chand, Abdi Nemera Emana

Open Access

https://doi.org/10.1080/2055074x.2016.1198545

Copy DOI

Abstract

Alkylation of benzene with ethanol was analyzed using shape selective boron–magnesium bimetallic HZSM-5 (Si/Al = 90) zeolite catalyst. The alkylation of benzene with ethanol (2:1 by volume) produces ethylbenzene as primary product and others like 1, 2-Diethylbenzene, 1, 4-Diethylbenzene, and xylene mixtures as secondary products. The physiochemical properties of catalyst were characterized by XRD, BET, TGA, FTIR, NH3-TPD, and FE-SEM. The feed and products were analyzed by gas chromatography and mass spectroscopy. B–Mg bimetallic catalysts supported on HZSM-5 zeolite catalyst with SAR = 90 were synthesized by the incipient wetness impregnation method and examined for alkylation of benzene with ethanol. Total metal loading of 5, 10, and 15% was used for catalyst synthesis. The highest selectivity of ethylbenzene (76.22%) was obtained by (Mg + B)-15%-HZSM-5 and the lowest ethylbenzene selectivity (49.15%) was obtained by (Mg + B)-5%-HZSM-5 using 2:1 benzene-to-ethanol ratio by volume. A reaction scheme with three parallel routes leading to the formation of ethylbenzene, diethylbenzene, and triethylbenzene was considered for the kinetic study. The kinetic parameters were determined using Langmuir–Hinshelwood–Hougen–Watson (LHHW)-type kinetic model. LHHW model could satisfactorily correlate the rate data and this model gives good fit between the experimental and calculated data.

Highlights

Porous solids with pores of the size of molecular dimensions, 0.3–2.0 nm in diameter are called molecular sieves
The highest selectivity of (d) ethylbenzene (76.22%) was obtained by (Mg + B)-15%-HZSM-5 and the lowest ethylbenzene
Zeolites are so special when compared to other crystalline inorganic oxide materials due to a combination of the following properties: the microporous character with uniform pore dimensions, allowing certain hydrocarbon molecules to enter the crystals while rejecting others based on too large a molecular size, the ion-exchange properties which allow to perform all sorts of ion exchange reactions, the ability to develop internal acidity which makes the zeolites interesting materials for catalyzing organic reactions, and the high thermal stability of the zeolites

Summary

Introduction

Porous solids with pores of the size of molecular dimensions, 0.3–2.0 nm in diameter are called molecular sieves. Some are crystalline with a uniform pore size and more described in detail by their crystal structure, for example, zeolites.. Zeolites are so special when compared to other crystalline inorganic oxide materials due to a combination of the following properties: the microporous character with uniform pore dimensions, allowing certain hydrocarbon molecules to enter the crystals while rejecting others based on too large a molecular size, the ion-exchange properties which allow to perform all sorts of ion exchange reactions, the ability to develop internal acidity which makes the zeolites interesting materials for catalyzing organic reactions, and the high thermal stability of the zeolites..

Methods

Results

Conclusion