PPT-Aromatic Reactions

Most common reactions for aromatics involve replacement of ring hydrogens by other atoms or groups substitution reactions Mechanism of Electrophilic Aromatic Substitution Reactions Electrophile. 15-8. Benzene undergoes substitution reactions with electrophiles.. Electrophiles attack benzene by substituting for a hydrogen atom, not addition to the ring.. Under the conditions of this type of reaction, ordinary non-aromatic conjugated polyenes would polymerize rapidly.. Orbitals. Natural gas?. Fig. 11.1. Aliphatic Hydrocarbon Structure Comparison. Bonding and Geometry. of Two-Carbon Molecules . 11.1 Structure and Physical. . Properties. Bitter almonds are the source of the aromatic compound benzaldehyde. Sources of Benzene. Some Facts About Benzene. Reacts mainly by substitution. Friedrich August Kekule’. The Orbital Model for Benzene. Dr. . Shatha. I . Alaqeel. 108 . Chem. Learning Objectives. By the end of chapter four the students will:. Understand the resonance description of structure of benzene. Understand the hybridization in benzene. Newehy. Chemistry Department, College of Science, King Saud University. http://fac.ksu.edu.sa/melnewehy. Aromatic . Compounds. The Structure of Benzene Ring. - . Benzene. is . the . parent hydrocarbon of . In 1825, Michael Faraday isolated a hydrocarbon called benzene, which consists of a six-carbon ring with alternating double bonds and the molecular formula C. 6. H. 6. . . Learning Goal . Describe the bonding in benzene; name aromatic compounds, and draw their line-angle structural formulas.. Reactions of Arenes. Reactions involving the ring. A. Reduction. a. Catalytic hydrogenation (Chapter 11.4). b. Birch reduction (Chapter 11.11). B. . Electrophilic. aromatic substitution (Chapter 12). 1. Nomenclature . of Polycyclic Aromatic Compounds. Polycyclic . aromatic compounds have two or more benzene rings fused together. 2. Naphthalene, anthracene and phenanthrene are obtained from . coal tar. MICHAEL FARADAY (1791-1867). first person to isolate and identify benzene. early benzene uses:. - . decaffeinate . coffee. - antiknock additive . in gasoline. - solvent in chem rxns. now we know benzene is a carcinogen!. UNIT I : Benzene & its derivatives. PART -I. Electrophilic Aromatic . Substitution Reactions. Aromatic compounds (Benzene) . undergo electrophilic aromatic substitution (. EAS).. Arene . (. Ar. -H) is the generic term for an aromatic . Reactions involving the ring. A. Reduction. a. Catalytic hydrogenation (Chapter 11.4). b. Birch reduction (Chapter 11.11). B. . Electrophilic. aromatic substitution (Chapter 12). C. . Nucleophilic. Our estimates of pressures and temperatures experienced by rocks during metamorphism are based on metamorphic reactions.. Mineral Reactions. There are two basic types of mineral reactions:. Continuous. Objective. To know about . electrophilic. substitution reactions. Success criteria. Understand . the mechanism of the . electrophilic. substitution reactions of . benzene. Understand this for . halogenation. The Discovery of Benzene. Benzene was discovered in . 1825. by the English chemist . Michael Faraday . (Royal Institution). Faraday called this new hydrocarbon “. bicarburet. of hydrogen”.. Faraday isolated benzene from a compressed illuminating gas that had been made by .