PPT-12.8 Aromatic Compounds

In 1825 Michael Faraday isolated a hydrocarbon called benzene which consists of a sixcarbon 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 lineangle structural formulas. Benzene is aromatic: a cyclic conjugated compound with 6 . . electrons. Reactions of benzene lead to the retention of the aromatic core. Types of Reactions. Electrophilic. substitution. Diazonium. Dr. . Sheppard. CHEM . 2412. Summer 2015. Klein (2. nd. ed. .) . sections. : 18.1, 18.2, 18.8, 18.3, 18.4, 18.5. Aromatic Compounds. Originally distinguished because of smell. Then noticed trends in reactivity. Most common reactions for aromatics involve replacement of ring . hydrogens. by other atoms or groups . (substitution reactions). Mechanism of Electrophilic Aromatic Substitution Reactions. Electrophile. Conjugation and Aromaticity. Which resonance form contributes more? .  . A B C D. A = C > B E. B > A = C. Conjugation and Aromaticity. Do you expect a difference in bond lengths?.  . a. yes b. no. Orbitals. Natural gas?. Fig. 11.1. Aliphatic Hydrocarbon Structure Comparison. Bonding and Geometry. of Two-Carbon Molecules . 11.1 Structure and Physical. . Properties. Leon. María. Elena. Larissa. Vanillin. Information. History of benzene. Ring structure. Functional groups. Hückel’s. rule. Vanillin. History of benzene. The . empirical formula for benzene had been long known, but its highly unsaturated structure was a challenge to determine. . 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 . Bitter almonds are the source of the aromatic compound benzaldehyde. Sources of . Benzene. Benzene. , C. 6. H. 6. , is the . parent hydrocarbon . of the . especially stable . compounds known . as . 1435-1436. 2014-2015. Learning Objectives. . Understand the. . resonance description of structure of benzene. Understand the hybridization in benzene. Understand the relation between the stability of benzene and resonance energy. Organic Chemistry. Second Edition. David Klein. Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.. Klein, Organic Chemistry 2e . 18.1 Introduction to Aromatic Compounds. Aromatic. compounds or . 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. Arenium Ion Mechanism . Some Aromatic Electrophilic Substitution Reactions Viz. Nitration, Sulphonation, Halogenation, Friedel- Crafts Reaction. Orientation & Reactivity in Mono Substituted Benzene. Dr. Geeta Singh. Assistant Professor. Department of Chemistry. D.D.U. Gorakhpur University, Gorakhpur. Introduction. Key . terms.. General reaction for aromatic electrophilic substitution.. Common reactions of AES.. D. r. . Zamir G Khan . Assistant Professor . H R Patel Institute of Pharmaceutical Education and Research Shirpur, Dist. Dhule, (M.S) 425405. Copyright @ Mr. Z G Khan. 2. If benzene is 1,3,5-cyclohexatriene as .