Organic Chemistry Chapter 18
Organic Chemistry Chapter 18 Chem 372-0
Popular in Organic Chemistry
Popular in Chemistry
This 10 page Class Notes was uploaded by Megan steltz on Friday October 7, 2016. The Class Notes belongs to Chem 372-0 at Eastern Michigan University taught by Gregg M. Wilmes in Fall 2016. Since its upload, it has received 5 views. For similar materials see Organic Chemistry in Chemistry at Eastern Michigan University.
Reviews for Organic Chemistry Chapter 18
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/07/16
Chapter 18 Electrophlic aromatic substitution Aromatic compounds are electron rich o Many electrons in π orbital o π bonds are less stable than σ bonds o aromaticity is retained in the product Mechanism of electrophlic aromatic substitution There are two more possible resonance structures for the above molecule 5 different types of reactions with aromatic compounds 1) Halogenation 2) Nitration 3) Sulfonation 4) Friedelcrafts Alkylation 5) Fridelcrafts Acylation Review of Lewis Dot/Resonance Structures H’s attached to carbons are not shown but they are still there No more than 8e on C, N, O Lone pairs are optional, charges are required Resonance structures, differ in the location of o Lone pairs o π bonds o atoms and σ bonds do not change Shows movement of e always start the arrow at the bond (σ or π) or a lone pair. End of arrow must point to atom or bond making new π bond Halogenation Reacts with Cl2 or Br2 Catalyst is FeCl3 or FeBr3 Reaction forms electrophile Nitration and Sulforation HNO3 reagent H2SO4 catalyst Sulfonation Reactions contains SO3 with H2SO4 Always going to be SO3 + H2O = H2SO4 fuming sulfuric acid FriedelCrafts Alkylation 1º alkyl halide = no carbocation Limitations of FC Alkyation Does not work if halogen is attached to Sp2 or Sp3 hybridized carbons. Carbocations in F.C. alkylation are prone to rearrangement problems with 1º or 2º RCl EAS or Substituted compounds The identity of the z, controls whether ortho, meta or para product(s) are formed Group already on the ring decides whether the reaction happens Some substitutions (activators) speed up the rate of EAS (relative to benzene) some (deactivators) slow down the rate. Activating/ deactivating directing effects Determined an electron withdrawing r donating capabilities of substance. Electron donating groups are activators Examples. Electron withdrawing groups are deactivating Electron donating or withdrawing can occur by Inductive effects resulting in differences in electronegativty Occur through σ bonds Alkyl groups are inductively donating Heteroatoms (O, N, X) are more electronegative than H so they are inductively withdrawing. Resonance effects Groups allow resonance structures that put + or – into ring Resonance donating group places negative charge in ortho and para position For O, N resonance donating is stronger than inductive withdrawing With F, Cl, Br, I inductive effects are stronger than resonance donating Resonance withdrawing groups Example + is ortho or para to subsistent
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'