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Dehydration of Alcohols
C - C X Y To make C=C need to eliminate X, Y. Elimination Reactions
C - C X Y 1. Concerted (x and y leave same time) 2. X leaves first 3. Y leaves first 3 ways to break 2 bonds
R-XR + + X - Alkene + H + E1 Reaction
Elimination 1 bond at a time E1
Substitution Elimination Rearrangement SN1SN1 E1 R+R+
SN1SN1 E1 SN1
C - C X H Strong base Dehydrohalogenation
What is the mechanism of dehydrohalogentation? C-D bond stronger than C-H bond. Isotope Effects
NaOEt k H /k D = 7 Isotope Effect
Isotope effect shows that C-H bond broken in the transition state. Bond Broken in Transition State
Change Element I > Br > Cl Element Effect
Same Side Opposite Side SYN vs. ANTI Elimination
Product Starting Material Energy Transition State
Elimination 2 Bonds at a time E 2
Put cyclohexanol and sulfuric acid in round bottom flask Fractional Distillation (steam distillation) collect distillate 80-85o Procedure
Dry product with K 2 CO 3
P T = P A + P B (Steam Distillation) Distil immiscible liquids
Potassium Permanganate KMnO 4 Baeyer Unsaturation Tests
Bromine and Cyclohexene
Br Bromonium Ion
Bromonium Ion Intermediate
Br - Mechanism
Dehydration of Alcohols. C - C X Y To make C=C need to eliminate X, Y. Elimination Reactions.
Dehydration of 2-methylcyclohexanol -- an E 1 reaction.
Alcohol Synthesis by Electrophilic Hydration: Thermodynamic Control 12-4 When other nucleophiles are present, they may also attack the intermediate carbocation.
7. Alkenes: Reactions and Synthesis Based on McMurry’s Organic Chemistry, 6 th edition.
CHAPTER 7 Haloalkanes. Haloalkane (alkyl halide): Haloalkane (alkyl halide): a compound containing a halogen covalently bonded to an sp 3 hybridized carbon;
Chapter 5 – Structure and Preparation of Alkenes Double bond - now dealing with sp 2 hybrid carbon YSU.
Dehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail.
ELIMINATION REACTIONS Chapter 5 Sect. 9.2 Elimination Reactions Dehydrohalogenation (-HX) and Dehydration (-H 2 O) are the main types of elimination.
Organic A Chapter 8 Alkenes (I) By Prof. Dr. Adel M. Awadallah Islamic University of Gaza.
99 Chapter 5: Structure and Preparation of Alkenes: Elimination Reactions Alkenes (olefins) are hydrocarbons that contain a carbon-carbon double bond and.
Chapter 81 CHE-240 Unit 3 Physical and Chemical Properties and Reactions of Alkenes and Alkynes CHAPTER EIGHT TERRENCE P. SHERLOCK BURLINGTON COUNTY COLLEGE.
Copyright 2002 © Mark Brandt, Ph.D. Addition Reactions.
Chapter 7 Alkenes and Alkynes I: Properties and Synthesis Elimination Reactions of Alkyl Halides.
Organic Chemistry …Alkenes…. Alkenes Hydrocarbons with one or more double bonds “Unsaturated” Have fewer than the maximum amount of hydrogens Have.
Chapter 8 Alkenes and Alkynes II: Addition Reactions.
Dr. Wolf's CHM 201 & Dehydrohalogenation of Alkyl Halides.
1 Reaction mechanisms. 2 Ionic Reactions
1 Reactions of Alkenes: Addition Reactions Disparlure: sex attractant of the female gypsy moth. (A type of pheromone.)
Elimination Reactions In addition to substitution, alkyl halides can also undergo elimination reactions, which lead to the formation of alkenes. As with.
© E.V. Blackburn, 2011 Alkenes C n H 2n. © E.V. Blackburn, 2011 Alkenes called unsaturated hydrocarbons also known as olefins (oleum, latin, oil; facere,
1 Reaction mechanisms. 2 Bond Polarity Partial charges.
WWU -- Chemistry ELIMINATION REACTIONS: WWU -- Chemistry Elimination Reactions Dehydrohalogenation (-HX) and Dehydration (-H 2 O) are the main types.
© 2011 Pearson Education, Inc. Chapter 9 Elimination Reactions of Alkyl Halides Competition Between Substitution and Elimination Organic Chemistry 6 th.
Chapter 8 Reactions of Alkenes Organic Chemistry, 6 th Edition L. G. Wade, Jr.
Alkenes and Alkynes 1 Properties and Synthesis. Elimination Reactions of Alkyl Halides.
Elimination Reactions of Alkyl Halides Chapter 9 “A pessimist finds difficulty in every opportunity. An optimist finds opportunity in every difficulty.”
Synthesis of Alkenes Major approaches to the synthesis of alkenes: Dehydrohalogenation of Alkyl Halides E2 mechanism – most useful E1 mechanism Dehalogenation.
Conversion of Alkenes to Vicinal Halohydrins. Cl 2 anti addition: only product H2OH2OH2OH2O H2CH2CH2CH2C CH 2 BrCH 2 CH 2 OH + Br 2 H2OH2OH2OH2O (70%)
Chapter 81 Reactivity of C=C Electrons in pi bond are loosely held. Electrophiles are attracted to the pi electrons. Carbocation intermediate forms. Nucleophile.
Unsaturated Hydrocarbons: Alkenes 108 Chem Chapter 3 1.
C Cl: CH 3 H.. S N 2 ANIMATION ENERGY PROFILE R. C Cl: CH 3 H :Br:.. S N 2 ANIMATION ENERGY PROFILE R.
S N 1 vs. S N 2 vs. E1 vs. E2 Factors affecting the type of reaction an alkyl halide undergoes include: Type of alkyl halide methyl, 1 o, 2 o, 3 o, allylic.
Chapter 8 Alkenes: Reactions and Synthesis. Alkenes react with many electrophiles to give useful products by addition (often through special reagents)
Alkenes Properties Nomenclature Addition Reactions.
5.14 Dehydrohalogenation of Alkyl Halides. X Y dehydrogenation of alkanes: X = Y = H dehydration of alcohols: X = H; Y = OH dehydrohalogenation of alkyl.
Reactions of Alkenes. CCl 4 Addition of HOX; X: Cl, Br Ozonolysis.
Chapter 8 Copyright © 2010 Pearson Education, Inc. Organic Chemistry, 7 th Edition L. G. Wade, Jr. Reactions of Alkenes.
© 2014 by John Wiley & Sons, Inc. All rights reserved. Chapter 8 Alkenes and Alkynes II: Addition Reactions.
Alkenes IB Chemistry Topic What is the difference between alkanes and alkenes? Which do you think would be more reactive?
WWU -- Chemistry ELIMINATION REACTIONS: ALKENES, ALKYNES Chapter 9.
Substitution & Elimination Reactions trans-rhodophytin.
ALKYLHALIDE By Mrs. Azduwin Khasri 23 rd October 2012.
Lecture 2 Acid Catalyzed Dehydration of Cyclohexanol.
Reagents and Conditions AS Chemistry. Oxidation of Alcohols Heat with Acidified Potassium Dichromate (orange to green) Under Distillation for Aldehydes.
Chemical Reactions of Alkanes and Alkenes. 1. Structure cyclohexane cyclohexene Or.
Properties of Hydrocarbons. Physical Properties of Alkanes Non polar compounds Insoluble in water Less dense than water and so will float on top.
Alkene Simple alkenes are named much like alkanes, using the root name of the longest chain containing the double bond. The ending is changed from - ane.
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