Alkylation reactions of aromatic hydrocarbons over ZSM5 zeolites

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CHAPTER – 1 INTRODUCTION

A. Alkylation of aromatic hydrocarbons

1.1 General introduction 1 1.2 Synthesis of ethylbenzene 2 1.3 Synthesis of isopropylbenzene 6 (Cumene)

1.4 Mechanism of benzene alkylation 9 over zeolite catalysts

1.5 Mechanism of deactivation of 11 zeolites catalysts in the

alkylation of aromatic hydrocarbons

B. Synthesis and characterization of zeolites

1.6 Synthesis 13 1.7 Composition 15 1.8 Structure of pentasil family 16 of zeolites

1.9 Physicochemical properties 20

C. Shape selective catalysis over 22 ZSM5 zeolites

D. Industrial processes bases on shape 24 selective zeolites

E. Scope of the present investigation 24

CHAPTER – 2 SYNTHESIS AND CHARACTERIZATION

2.1 Synthesis of ZSM5 zeolite 28 and modified catalysts

2.2 Experimental techniques 30 2.3 Results and discussion 36

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B. Thermal analysis 42

C. Surface area 48

D. Adsorption 52

E. Characterization of acid sites 60

F. Scanning electron microscopy 68

CHAPTER – 3 STUDIES ON THE ALKYLATION OF BENZENE WITH ETHANOL 3.1 Introduction 71

3.2 Experimental 74

3.3 Results and discussion 79

A. Influence of temperature 79

B. Influence of contact time 84

C. Influence of benzene/ethanol 87

mole ration D. Influence of time-on-stream 93

E. Alkylation of benzene over modified catalysts 98

F. Effect of steam injection 113

G. Stability of ZSM5 catalyst 117

H. Influence of calcinations 120

temperature on alkylation activity I. Determination of external 126

diffusion effects J. Determination of energy of 126

activation K. Mechanism 129

L. Conclusions 131

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WITH ETHANOL

4.1 Introduction 133

4.2 Experimental 134

C. Influence of toluene/ethanol 140

mole ratio. D. Influence of time-on-stream 148

E. Influence of SiO 2 /Al 2 O 3 ratio 150

on alkylation activity F. Alkylation of toluene over 160

modified catalysts G. Effect of pyridine injection 171

on selectivity to para ethyl toluene H. Mechanism 173

I. Conclusions 174

CHAPTER – 5 STUDIES ON THE ALKYLATION OF BENZENE WITH ISOPROPANOL 5.1 Introduction 176

5.2 Experimental 178

C. Influence of benzene/isopropanol 182

mole ratio D. Propylation of benzene using 182 n-porpanol as alkylating agent

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F. Influence of benzene over 196

modified catalysts G. Influence of calcination 203

temperature on selectivity to isopropylbenzene H. Influence of pyridine injection 208

on selectivity to isopropylbenzene I. Mechanism 210

J. Conclusions 211

SUMMARY 213

REFERENCES 229

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