Alkylation Reactions To Produce Ethylbenzene, Cumene, Cymenes And Methyl Phenols Such As Cresols, Xylenols, Anisoles, Are Of Major Importance To The Petrochemical Industry. The Present Work Is Devoted To The Alkylation Of Lower Aromatics Such As Benzene, Toluene And Phenol With C1-C3 Alcohols And Acetone Over Modified Zeolites Such As Nax And Mordenite. The Focus Through Out The Thesis Is On Heterogeneous Catalysis With Reaction Systems Of Commercial Importance. The Main Areas Of Enquiry Are, Developing A Modified Catalyst Of Good Activity And Selectivity, Finding Out Product Distribution Varying Reaction Parameters, Searching A Reaction Mechanism For The Different Reactions And Finding Out An Appropriate Kinetic Model And Thus Rate Of A Reaction. Alkylation Processes Are Traditionally Conducted Over Friedel-Craft Catalysts Such As HF, And H2SO4 Or Lewis Acid Such As Alcl3 And BF3. The Use Of These Substances Involve Technological And Environmental Problems Due To Their Corrosive Nature And The Difficulty Of Recycling And Separation From The Product. Presently These Are Being Replaced By Zeolite Catalyst Having High Thermal Stabilities, Shape Selective Properties, Regenerability, Non-Corrosive And Eco-Friendly Nature. The Industrial Processes Use Mainly Alkenes As The Alkylating Agents. The Direct Use Of Alcohols, Instead Of Olefins As An Alkylating Agent Has Some Advantages. The Present Work Is, Therefore, Focused On The Alkylation Reactions Of Benzene With Isopropanol, Ethanol And Acetone; Toluene With Isopropanol And Phenol With Methanol Over Modified Nax And H-Mordenite Zeolites. The Nax Zeolite Was Modified By Exchanging Its Sodium Ions With Cerium Ions And Five Different Catalysts, Designated As Cex2, Cex5, Cex7, Cex10 And Cex12, Were Prepared. Study Of The Temperature Programmed Desorption Of Ammonia With The Modified Catalysts Indicated Changes In Both Quantity And Strength Of The Acid Sites Responsible For Alkylation Reactions. Cex10 Was Found To Be The Most Active Catalyst Among Six Different Catalysts Tested.
Thesis Submitted To Indian Institute Of Technology, Kharagpur ,For The Award Of The Degree Of Doctor Of Philosophy In Chemical Engineering By Sanghamitra Barman Under The Supervision Of Prof. N. C. Pradhan & Prof. J. K. Basu Department Of Chemical Engineering, Indian Institute Of Technology Kharagpur, India .