PPT-BENZENE & its Aromaticity

MARULSELVAN Syllabus Benzene and Aromaticity 41 Concept of aromaticity Huckels rule for aromaticity identification of aromatic Nonaromatic and anti aromatic systems based on planarity conjugation and Huckels rule. 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.. and the Novel Boron-Nitrogen Bond: A Benzene Mimic. Jeremy . Schifberg. Liu Group. Background: . Aromaticity. Definition:. A chemical property whereby a conjugated ring exhibits a stronger-than-expected stabilization due to its electrons being free to cycle around the ring atoms. A hybrid of a single and a double bond is formed, with each bond in the ring identical to the next.. 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. How are the lessons? . Too fast? long? slow? Boring?. 2. . How are you finding the pace of the course? . Difficult? Easy? Challenging?. 3. What do you wish we could do more of in class? Less of in class?. Arenes are . aromatic hydrocarbons . containing 1 or more benzene rings. . A benzene ring is a ring of . 6 carbon atoms. , each of which is also bonded to a hydrogen atom, with molecular formula . C. By Taylor Hatchett. What is Benzene?. Chemical. C. olorless or light yellow. L. iquid at room temperature. Has a sweet odor . H. ighly flammable. E. vaporates quickly into air. What is Benzene?. Vapor is heavier than air. 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. 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. . 15. TH. FEB 2012. PRESENTED BY. HARIDASAN V A. CAPACITY AND TECHNOLOGY. Plant capacity : 290,000 MT of Cumene per year. On stream factor : 8,000 Hours. Hourly production rate : 36.25 MT/hr of Cumene . Benzene. Colorless liquid with sweet scent often produced from petroleum . Flammable (flashpoint below 37.8 °C). Carcinogenic, reproductive toxin . Toxic, skin irritation and burns. Extremely toxic to aquatic life. Attack. Electrophilic Aromatic Substitution. Electrophile substitutes for a hydrogen on the benzene ring.. Mechanism. =>. Bromination of Benzene. Requires a stronger electrophile than Br. 2. .. Use a strong Lewis acid catalyst, FeBr. with the molecular formula . C. 6. H. 6. . benzene is a . colorless. and . highly flammable . liquid with a . sweet smell . and a relatively . high melting point. .. What is Benzene ?. Molecular orbital structure of benzene. AROMATIC HYDROCARBONS-. -------Benzene. Synonyms. Benzol. , . Benzole. , . Benzolene. , Coal naphtha, Phenyl hydride, . Annulene. , Carbon oil, . Cyclohexatriene. , Mineral naphtha,. Motor benzol, Phene, Pyrobenzol, Pyrobenzole..