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Alkylation of Benzene on Immobilized Phosphotungstic Acid

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Alkylation of Benzene on Immobilized Phosphotungstic Acid East Tennessee State University Digital Commons @ East Tennessee State University Electronic Theses and Dissertations Student Works 12-2020 Alkylation of Benzene on Immobilized Phosphotungstic Acid Kofi Kankam East Tennessee State University Follow this and additional works at: https://dc.etsu.edu/etd Part of the Organic Chemistry Commons Recommended Citation Kankam, Kofi, Alkylation" of Benzene on Immobilized Phosphotungstic Acid" (2020). Electronic Theses and Dissertations. Paper 3847. https://dc.etsu.edu/etd/3847 This Thesis - unrestricted is brought to you for free and open access by the Student Works at Digital Commons @ East Tennessee State University. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Digital Commons @ East Tennessee State University. For more information, please contact [email protected]. Alkylation of Benzene on Immobilized Phosphotungstic Acid ________________________ A thesis presented to the faculty of the Department of Chemistry East Tennessee State University In partial fulfillment of the requirements for the degree Master of Science in Chemistry ______________________ by Kofi Kankam December 2020 _____________________ Dr. Aleksey Vasiliev, Chair Dr. Ismail Kady Dr. Hua Mei Keywords: alkylbenzenes, sol-gel synthesis, phosphotungstic acid, catalyst ABSTRACT Alkylation of Benzene on Immobilized Phosphotungstic Acid by Kofi Kankam Linear alkylbenzenes (LAB) are key intermediates in the synthesis of linear alkylbenzene sulfonate surfactants that are used in the manufacture of detergents. Production of LAB with traditional Lewis acids as catalysts, such as hydrofluoric acid, results in the formation of large amounts of toxic wastes and corrosion of industrial equipment. Phosphotungstic acid (PTA) has gained much attention in recent years as a solid catalyst for various alkylation reactions. This research work aims to develop a novel material based on PTA-containing silica gel, which can effectively catalyze LAB synthesis. Sol-gel synthesis of silica gel in the presence of PTA and tetraethyl orthosilicate as precursors produced a mesoporous aterial containing covalently embedded PTA clusters. Obtained superacidic catalyst demonstrated high catalytic activity in liquid-phase alkylation of benzene by various alkenes. Covalent embedding of catalytically active HPA clusters prevents their leaching from the catalyst surface, which enabled its excellent catalytic properties. 2 Copyright 2020 by Kofi Kankam All Rights Reserved 3 DEDICATION This work is dedicated to my family and loved ones. 4 ACKNOWLEDGEMENTS I would like to express my sincerest gratitude to Dr. Vasiliev, my research advisor for the opportunity to be a part of his research group and also for his guidance and patience throughout this journey. I would like to thank Dr. Ismail Kady and Dr. Hua Mei for accepting to be a part of my Advisory committee and for their help on my thesis. I would like to thank Dr. Reza Mohseni for his help with instrumentations and analysis for my research work. I am grateful to Maria Kalis for her help in administrative and organizational aspects throughout my time in graduate school. I would also like to thank Anastasia Kuvaysakaya, my research colleague for her help and support during the entire project. Special gratitude to the American Chemical Society Petroleum Research Fund for supporting this research. 5 TABLE OF CONTENTS ABSTRACT .................................................................................................................................... 2 DEDICATION ................................................................................................................................ 4 ACKNOWLEDGEMENTS ............................................................................................................ 5 TABLE OF CONTENTS ................................................................................................................ 6 LIST OF TABLES .......................................................................................................................... 8 LIST OF FIGURES ........................................................................................................................ 9 LIST OF ABBREVIATIONS ....................................................................................................... 10 CHAPTER 1. INTRODUCTION ................................................................................................. 11 Linear Alkylbenzenes ................................................................................................................ 11 Current Technologies in LAB Manufacture ............................................................................. 13 Heterogeneous Catalysts ........................................................................................................... 15 Heteropolyacids (HPAs) ........................................................................................................... 17 Immobilized Heteropolyacids ................................................................................................... 20 Research Objectives .................................................................................................................. 22 CHAPTER 2. EXPERIMENTAL METHODS ............................................................................ 24 Chemicals and Reagents ........................................................................................................... 24 Preparation of Catalyst .............................................................................................................. 25 Alkylation of Benzene ............................................................................................................... 25 General Procedure ................................................................................................................. 25 Effect of Alkylation Conditions ............................................................................................ 25 Study of Deactivation and Regeneration of the Catalyst ...................................................... 26 Instrumental Characterization ................................................................................................... 27 Fourier Transform Infrared Spectroscopy (FT-IR) ............................................................... 27 Elemental Analysis ............................................................................................................... 27 Scanning Electron Microscopy ............................................................................................. 27 Porosity ................................................................................................................................. 27 Particle Size Distribution ...................................................................................................... 27 GC-MS Analysis ................................................................................................................... 28 CHAPTER 3. RESULTS AND DISCUSSION ............................................................................ 29 Alkylation of Benzene ............................................................................................................... 29 Effect of Temperature ........................................................................................................... 29 6 Effect of the Amount of Catalyst .......................................................................................... 30 Effect of Alkene to Benzene Molar Ratio ............................................................................ 30 Phenylalkane Isomers Distribution ....................................................................................... 31 Isomerization of Alkenes ...................................................................................................... 32 Regeneration of the Catalyst ................................................................................................. 32 Instrumental Characterization ................................................................................................... 32 SEM Imaging ........................................................................................................................ 32 Particle Size Distribution ...................................................................................................... 33 Formation of Carbon Deposits on the Catalyst ..................................................................... 33 BET Surface Area ................................................................................................................. 34 FT-IR Spectroscopy .............................................................................................................. 34 Discussion ................................................................................................................................. 36 CONCLUSIONS........................................................................................................................... 40 REFERENCES ............................................................................................................................. 41 VITA ............................................................................................................................................. 48 7 LIST OF TABLES Table 1. Chemicals Used .............................................................................................................
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