PPT-Chapter 18 Aromatic Compounds

Organic Chemistry Second Edition David Klein Copyright 2015 John Wiley amp Sons Inc All rights reserved Klein Organic Chemistry 2e 181 Introduction to Aromatic Compounds Aromatic compounds or . 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. 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.. The painkiller morphine is obtained from opium, the dried sap of unripe seeps of the poppy . P. apaver. . somniferum. Amines are relatives of ammonia and are usually classified as primary, secondary or tertiary. 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. Aromatic CompoundsEssential feature: benzene-like ringscapsaicinHOCH3ONHO An example: CCCCCC CCCCCC Polycyclic Aromatic Compounds Polycyclic Aromatic Compounds naphthaleneanthracenephenanthrenepyreneb 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. 15-5. Molecules containing several fused benzene rings are called . polycyclic benzenoid. or . polycyclic aromatic hydrocarbons. (. PAHs. ).. Common names are used for these systems, since there is no simple naming system for them.. Session Objectives. Introduction nitro compounds. Nomenclature. Structure and physical properties. Preparation of nitro compounds. Chemical reactions. Cyanides and isocyanides. . General method of preparation. 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 . 22.1 Hydrocarbons. Organic Chemistry. includes almost all carbon compounds. Not limited to compounds found in living cells. Hydrocarbon: organic compound made of only hydrogen and carbon atoms. hydrocarbons. 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. 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..