PPT-Learning Outcomes Introduction: Electrophilic Aromatic Substitution

Arenium Ion Mechanism Some Aromatic Electrophilic Substitution Reactions Viz Nitration Sulphonation Halogenation Friedel Crafts Reaction Orientation amp Reactivity in Mono Substituted Benzene. Most common reactions for aromatics involve replacement of ring . hydrogens. by other atoms or groups . (substitution reactions). Mechanism of Electrophilic Aromatic Substitution Reactions. Electrophile. M.ARULSELVAN. Syllabus. Benzene and Aromaticity. 4.1 Concept of aromaticity:. . . -Huckel's rule for aromaticity, . -identification of aromatic, . -Non-aromatic and anti aromatic systems based on planarity, conjugation and Huckel's rule.. 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.. 16-6. Naphthalene is activated toward electrophilic substitution.. Naphthalene undergoes electrophilic substitution rather than addition.. Naphthalene is activated with respect to electrophilic aromatic substitution. Bromination at C1 occurs without a catalyst under mild conditions.. Carbocations. Substitution and . β. -elimination reactions at C(sp. 3. )-X. Electrophilic addition to . nuclephilic. C=C . π. bonds. Substitution . at . nuclephilic. C=C . π. . bonds. Nuclephilic. Heterocyclic. Chemistry. Heterocyclic. Chemistry. Five-. membered. . Heterocycles. Pyrrole. , Furan and . Thiophene. Heterocyclic Chemistry. Five Membered Heterocycles-Introduction. The main reason for the study of pyrrole came from the work on the structure of haem; the blood respiratory pigment, and the chlorophyll; the green photosynthetic pigment of plants.. 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 . . as a tool for structure determination. Experimental:. Dissolve the sample in DCM (1 mL). Add . dropwise. a 1% . bromine solution. of DCM. Positive test, if red color disappears . Conclusion:. The sample contains a multiple bond, which undergoes . 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. 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). Fall . 2018. Schedule of . day. PPE . and Pre-lab check . – at the door. Quiz. Recitation. Safety. Put bags away. Goggles. Gloves. Lab Coat. Lab part 1. IR . Review. Lab part 2. Due . Dates. . Today. 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!. 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..