Elimination Reactions:
|
|
- Lee Alfred Hudson
- 5 years ago
- Views:
Transcription
1 Elimination Reactions: These are just reverse of addition reactions. These involve the removal of atoms or group of atoms from a molecule. Elimination reactions are generally endothermic and take place on heating. Elimination reactions are classified into two categories. -Elimination reactions or 1,1-elimination reactions -Elimination reactions or 1,2-elimination reactions
2 (i) -Elimination reactions: Those elimination reactions in which both the atoms or groups are removed from the same carbon atom of the molecule. This reaction is mainly given by gem. di or trihalides having atleast one - atom. Products of these reactions are halocarbenes. Alc. KO / CX 3 CX 2 + X + Dichloro carbene Alc. KO / C 2 X 2 CX + X + Monohalo carbene
3 (ii) -Elimination reactions: Those elimination reactions in which removal of functional group (leaving group) from -carbon atom and other group (generally -atom) from -C-atom take place are called -elimination reactions. In this reaction there is loss of two bonds and gain of one bond. -Elimination reactions are divided into following types. E 1 E 2 E 1 cb base) (Elimination unimolecular) (Elimination bimolecular) (Elimination unimolecular conjugate
4 Examples of elimination reactions: Dehydrohalogenation: Removal of hydrogen halide from a molecule is known as dehydrohalogenation. Example: Dehydrohalogenation of alkyl halides in presence of alcoholic KO. 2 C C 2 Ethyl bromide Alc. KO / 2 C C 2 + Ethene
5 E 1 mechanism: E 1 stands for elimination unimolecular. Consider the reaction of t-alkyl halides (tbutyl bromide) with alcoholic KO solution to form alkene (2-methyl propene). 2 C C t - Butyl bromide - alcoholic KO/ 2 C C 2 - Methyl propene +
6 The mechanism of the reaction involves the two steps. The first step involves the slow ionization of bromide to form carbocation. Slow 3 C C C C t - Butyl bromide t - Butyl carbocation
7 The second step is fast step and involves the removal of atom by base from carbocation to form the final product. C 2 5 O - + C C + Fast 2 C 2 5 O + 2 C C From the kinetic studies it is found that the rate of this reaction depends only upon the concentration of alkyl halide and independent of conc. of the base. Rate [(C3)3 C ] Rate=k[(C3)3C].Unimolecular reaction
8 E 2 mechanism: E 2 stands for elimination bimolecular. Consider the reaction between primary alkyl halide such as ethyl bromide and alcoholic KO to form alkene (ethene). 2 C C 2 alcoholic KO 2 C C 2 +
9 The mechanism of this reaction is single step and involves the formation of transition state. Thus E 2 reactions are concerted reactions. In E 2 reactions, both the leaving groups should be antiperiplanar i.e., both leaving groups should be in the same plane but should have anti configuration (i.e., angle is 180º). - O 5 C 2 C 2 5 O - + C C C C - C 2 5 O + 2 C C Transition State
10 From kinetic studies it has been found that rate of this reaction depends both upon conc. of C25 and the base. Rate [C25][C25O ] Rate = k[c25][c25o ] biomolecular reaction
11 E 1 cb mechanism: E 1 cb stands for elimination unimolecular conjugate base. It is two steps process and involved the formation of conjugate base (carbanion) of the reactant. Thus E 1 cb mechanism is limited to substrates which can be stabilize the carbanion as reaction intermediate by resonance or by -I effect. In this type of mechanism the β-hydrogen atom of the reactant should be highly acidic so that it can be easily removed as proton to give carbanion.
12 Examples: C 2 5 O - F 3 C CCl 2 F 2 C CCl 2 + F 5 C 6 C 2 C 2 F C 2 5 O - 5 C 6 C C 2 + F This process of elimination involves two steps like E 1 mechanism. In E 1 mechanism, X leaves first followed by. In the E 1 cb mechanism, the leaves first and then the X. This mechanism thus involves a carbanion intermediate as follows:
13 F 3 C C Cl + C 2 Fast 5 O- F C - 3 C Cl Cl Cl Carbanion or Congugate base of substrate + C 2 5 O The carbanion so formed is stabilized by I effect of CF3 & Cl atoms. F F C Cl F 2 C CCl 2 + F- F C - Cl Carbanion Product
14 Orientation in elimination reactions: It is found that elimination in a symmetrical organic halide gives rise to a single alkene. e.g., 2- chloropropane forms only one product; propene. 2 C C 3 C C Cl alcoholic KO 3 C C C 2
15 But in an unsymmetrical alkyl halide, elimination may proceed in more than one direction and a mixture of isomeric alkenes results. e.g., 2- omobutane forms two products. C 3 C 2 C Alcoholic KO/ 3 C C C Butene-2 (major) 3 C C 2 C C 2 Butene-1 (minor) Thus, if the substrate is unsymmetrical then there will be more than one product. The major product of the reaction can be known by two emperical rules.
16 1. Saytzeff rule : According to this rule, major product is the most substituted alkene i.e., major product is obtained by elimination of - atom from that β-carbon atom which has the least number of -atoms or that β-carbon atom which is most substituted and the product is called Saytzeff product. C 3 Cl C 2 C alcoholic KO KO 3 C C C Butene - 2 major (80%) 3 C C 2 C C 2 Butene - 1 minor (20%)
17 2. ofmann rule: According to this rule the major product is always least substituted alkene i.e., major product is formed by elimination of - atom from that β-carbon atom which has maximum number of -atoms. i.e., β-carbon atom which is least substituted. The product of the reaction is known as ofmann product. 3 C C alcoholic KO C 2 C 3 C C C 2 C C 2 Major product
18 It is found that: 1. In E 1 reactions, the product formation always takes place by Saytzeff rule. 2. In E 1 cb reactions, the product formation always takes place by ofmann rule. 3. In E 2 reactions, product formation takes place by Saytzeff as well as ofmann rule. In almost all E 2 reactions product formation takes place by Saytzeff rule. Only in following cases product formation takes place by ofmann rule. (i) Dehydrohalogenation of alkyl halides when leaving group is very poor or bulky e.g.,
19 F 3 C C 2 C 2 C Alcoholic KO + 3 C C 2 C 2 C C 2 3 C C 2 C C (70%) ofmann product 30% Saytzeff product 3 C C C S + 3 C O - 3 C C C C 2 + ofmann product (Major) Sulphonium ion 3 C C C + 3 C S + 2 O Saytzeff product (Minor)
20 3 C C 2 C N + ( ) 3 Ammonium ion O - 3 C C 2 C C 2 ofmann product (Major) + 3 C C C + ( ) 3 N + Saytzeff product (minor) 2 O
21 (ii) 1º and 2º alkyl halides give ofmann product when the size of the base is bulky e.g., Na or K salt of t-butoxide. ( ) 3 C OK/ 3 C C 2 C + 3 C C 2 C C 2 3 C C C ofmann product (80%) Saytzeff product (20%)
22 (iii)1º and 2º alkyl halides having quaternary carbon give ofmann product due to steric hindrance at β-carbon atom. 3 C C C 2 C ofmann product (major) Alcoholic KO + 3 C C C 2 C C 2 3 C C C C Saytzeff product (minor)
23 (iv)when an alkyl halide contains one or more double bond. 2 C C C 2 C C - O 2 C C C C C + 2 C C C 2 C C offmann product (80%) Saytzeff product (20%)
24 Dehalogenation: Removal of halogens from a molecule is known as dehalogenation. Vicinal dihalides undergo dehalogenation when they are heated with solution of NaI in acetone or with Zn dust and ethanol or Ag/ethanol. 3 C C C NaI Acetone 3 C C C + I 2 + 2Na 3 C C C Zn dust Ethanol 3 C C C + Zn 2
25 Dehalogenation by NaI takes place by an E 2 mechanism as follows: + I 3 C C C 3 C C C + I + I + I I 2 + Na Na
26 Dehalogenation by Zn or Ag also takes place by E 2 mechanism as follows: Zn 3 C C C 3 C C C + Zn 2
27 Stereochemistry of dehalogenation reactions: Dehalogenation reactions are anti elimination reactions. These reactions are also stereoselective as well as stereospecific. Geometry of alkene formed during dehalogenation reaction depends on the configuration of the, -dihalo alkanes in which and carbons are chiral.on dehalogenation: Meso form gives trans alkene. (+) or (-) form gives cis alkene.
28 (+) or (-) form cis-2-butene C C Zn/C 2 5 O C 3 C C Meso-2, 3-dibromo butane trans-2-butene C C Zn/C 2 5 O 3 C C C
29 Dehydration: Removal of water from a molecule is known as dehydration. Dehydrating agents for alcohols are conc. 2SO4/, KSO4/, 3PO4/, anhydrous Al2O3/, anhydrous PCl5/, anhydrous ZnCl2/, BF3/ and P2O5/. The decreasing order of reactivity of alcohols for dehydration is as follows: 3 alcohol > 2 alcohol > 1 alcohol
30 O 2 C C 2 Ethyl alcohol 2 SO 4 / 2 C C O Ethene O C 3 C N 2 P 2 O 5 / 3 C C N + 2 O
Classes of Alkenes. Alkenes and Alkynes. Saturated compounds (alkanes): Have the maximum number of hydrogen atoms attached to each carbon atom.
Alkenes and Alkynes Saturated compounds (alkanes): ave the maximum number of hydrogen atoms attached to each carbon atom. Unsaturated compounds: ave fewer hydrogen atoms attached to the carbon chain than
More informationthere general method to synthesize alkenes a. acidic conditions acid catalyzed dehydration of alcohols to alkene H H H H H OH 2 H H + H 2 O H H
there general method to synthesize alkenes a. acidic conditions acid catalyzed dehydration of alcohols to alkene O 2 SO 4 heat O 2 SO 4 heat O 2 O 2 2 SO 4 heat + SO 4 + 2 O + SO 4 + 2 O + 2 SO 4 limitation;
More informationElimination Reactions Heating an alkyl halide with a strong base causes elimination of a. molecule of HX
Elimination eactions eating an alkyl halide with a strong base causes elimination of a molecule of X 1. Potassium hydroxide dissolved in ethanol and the sodium salts of alcohols (such as sodium ethoxide)
More informationPreparation of Alkyl Halides, R-X. Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): R + X X 2.
Preparation of Alkyl alides, R-X Reaction of alkanes with Cl 2 & Br 2 (F 2 is too reactive, I 2 is unreactive): UV R + X 2 R X or heat + X This mechanism involves a free radical chain reaction. A chain
More informationH H C C. Alkenes C n H 2n unsaturated hydrocarbons. C 2 H 4 ethylene. Functional group = carbon-carbon double bond
Alkenes C n H 2n unsaturated hydrocarbons C 2 H 4 ethylene H H C C H H Functional group = carbon-carbon double bond sp 2 hybridization => flat, 120 o bond angles σ bond & π bond => H 2 C=CH 2 No rotation
More informationDehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail
Dehydrohalogenation of Alkyl Halides E2 and E1 Reactions in Detail b-elimination Reactions Overview dehydration of alcohols: X = H; Y = OH dehydrohalogenation of alkyl halides: X = H; Y = Br, etc. X C
More informationElimination Reactions The E2 Mechanism
Elimination Reactions The E2 Mechanism The E2 Mechanism X X- B: B- δ- B:- δ+ R 1 δ- R 2 δ+ X δ- The E2 Mechanism R 3 R 4 transition state Free energy (G) Eact B:- B R 1 R 2 X R 1 R 2 R 3 R 4 R 4 R 3 X:-
More informationNucleophilic Substitution and Elimination
Nucleophilic Substitution and Elimination Alkyl halides react with a nucleophile in one of two ways. Either they eliminate an X to form an alkene, or they undergo a substitution with the nucleophile, Nu,
More informationORGANIC CHEMISTRY- 1
ORGANIC CEMISTRY- 1 ALKENES Alkenes are also called Olefins (C n 2n ) unsaturated hydrocarbons. Alkenes occur abundantly in nature. Ethylene ( 2 C=C 2 ) is a plant hormone that induces ripening in fruit.
More informationBasic Organic Chemistry Course code : CHEM (Pre-requisites : CHEM 11122)
Basic Organic Chemistry Course code : CHEM 12162 (Pre-requisites : CHEM 11122) Chapter 01 Mechanistic Aspects of S N2,S N1, E 2 & E 1 Reactions Dr. Dinesh R. Pandithavidana Office: B1 222/3 Phone: (+94)777-745-720
More informationElimination reactions
Chapter 9 Elimination reactions E2 and E1 reactions Competition between S N and E Elimination reactions Ch 9 #2 elimination and/or substitution 2 mechanisms ~ E2 and E1 E2: bimolecular elimination rxn
More informationHalo Alkanes and Halo Arenes
alo Alkanes and alo Arenes Short Answer Questions: **1. Write the isomers of the compound having formula C 4 9 Br? Sol. There are five isomers of C 4 9 Br. These are: 2-bromobutane is expected to exhibit
More informationEssential Organic Chemistry. Chapter 9
Essential Organic Chemistry Paula Yurkanis Bruice Chapter 9 Substitution and Elimination Reactions of Alkyl Halides 9.1 How Alkyl Halides React Substitution Reactions One group takes the place of another.
More informationChapter 6 Ionic Reactions-Nucleophilic Substitution and Elimination Reactions of Alkyl Halides"
Chapter 6 Ionic Reactions-Nucleophilic Substitution and Elimination Reactions of Alkyl Halides" t Introduction" The polarity of a carbon-halogen bond leads to the carbon having a partial positive charge"
More informationDr. Anand Gupta Mr Mahesh Kapil
Dr. Anand Gupta Mr Mahesh Kapil 09356511518 09888711209 anandu71@yahoo.com mkapil_foru@yahoo.com Preparation of Haloalkanes From Alkanes Alkenes Alcohols Carboxylic Acids (Hundsdicker Reaction) Halide
More informationHydrogen iodide is a strong acid and will drive the reverse reaction, meaning the forward reaction will not occur.
EM 261 Oct 18, 2018 Photosynthesis and Related Reactions O 2 2 O 6 12 O 6 2 O N 3, S, Fe, u, o, other Natural Products D-Glucose R O R OR Ionic substitution S N 1 & R X X 2 hv Petroleum/ Alkanes R N 2
More information7. Haloalkanes (text )
2009, Department of hemistry, The University of Western Ontario 7.1 7. aloalkanes (text 7.1 7.10) A. Structure and Nomenclature Like hydrogen, the halogens have a valence of one. Thus, a halogen atom can
More informationMUNISH KAKAR s INSTITUTE OF CHEMISTRY
REACTONS & PREPARATON OF HALOGENATED COMPDS. WS#3 Q1. Reagent for preparing a chloroalkane from an alcohol is (a) SOCl 2 (b) HCl/ZnCl 2 (c) PCl 3 (d) All of these Q2. n the addition of H to propene in
More informationCHAPTER 7. Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination
CHAPTER 7 Further Reactions of Haloalkanes: Unimolecular Substitution and Pathways of Elimination 7-1 Solvolysis of Tertiary and Secondary Haloalkanes The rate of S N 2 reactions decrease dramatically
More informationHow alkyl halides react
Chapter 10 1 How alkyl halides react δ+ δ- RCH 2 -X X= halogen X = higher EN C = lower EN This polar carbon-halogen bond causes alkyl halide to undergo S N and elimination reaction. 2 The mechanism of
More informationClasses of Halides. Chapter 6 Alkyl Halides: Nucleophilic Substitution and Elimination. Polarity and Reactivity. Classes of Alkyl Halides
rganic hemistry, 5 th Edition L. G. Wade, Jr. hapter 6 Alkyl alides: Nucleophilic Substitution and Elimination lasses of alides Alkyl: alogen, X, is directly bonded to sp 3 carbon. Vinyl: X is bonded to
More informationChapter 7 Alkenes; Elimination Reactions
hapter 7 Alkenes; Elimination Reactions Alkenes Alkenes contain a carbon-carbon double bond. They are named as derivatives of alkanes with the suffix -ane changed to -ene. The parent alkane is the longest
More informationCHEM Lecture 7
CEM 494 Special Topics in Chemistry Illinois at Chicago CEM 494 - Lecture 7 Prof. Duncan Wardrop ctober 22, 2012 CEM 494 Special Topics in Chemistry Illinois at Chicago Preparation of Alkenes Elimination
More informationChapter 8 Alkyl Halides and Elimination Reactions
Organic Chemistry, Second Edition Janice Gorzynski Smith University of Hawai i Chapter 8 Alkyl Halides and Elimination Reactions Prepared by Rabi Ann Musah State University of New York at Albany Copyright
More information+ + CH 11: Substitution and Elimination Substitution reactions
C 11: Substitution and Elimination Substitution reactions Things to sort out: Nucleophile Electrophile -- > substrate Leaving Group S N 2 S N 1 E 1 E 2 Analysis Scheme Kinetics Reaction profile Substrates
More informationREACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION
REACTIONS OF HALOALKANES - SUBSTITUTION AND ELIMINATION Haloalkanes (also known as halogenoalkanes and alkyl halides) are organic compounds where one of the hydrogens of an alkane or cycloalkane has been
More informationChapter 8 Alkenes and Alkynes II: Addition Reactions "
Chapter 8 Alkenes and Alkynes II: Addition Reactions Additions to Alkenes Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds Alkenes are electron rich The π
More informationChapter 11: Nucleophilic Substitution and Elimination Walden Inversion
hapter 11: Nucleophilic Substitution and Elimination Walden Inversion (S)-(-) Malic acid [a] D = -2.3 Ag 2, 2 Pl 5 l Ag 2, 2 ()-2-hlorosuccinic acid l (-)-2-hlorosuccinic acid Pl 5 ()-() Malic acid [a]
More informationBut in organic terms: Oxidation: loss of H 2 ; addition of O or O 2 ; addition of X 2 (halogens).
Reactions of Alcohols Alcohols are versatile organic compounds since they undergo a wide variety of transformations the majority of which are either oxidation or reduction type reactions. Normally: Oxidation
More informationChapter 6: Organic Halogen Compounds; Substitution and Elimination Reactions
Chapter 6: Organic Halogen Compounds; Substitution and Elimination Reactions Halogen compounds are important for several reasons. Simple alkyl and aryl halides, especially chlorides and bromides, are versatile
More informationElimination Reactions The E2 Mechanism
Elimination Reactions The E2 Mechanism The E2 Mechanism X B: δ- B:- δ+ R 1 C δ- R 2 C δ+ X δ- The E2 Mechanism R 3 R 4 transition state Free energy (G) Eact B:- B R 1 R 2 C C X R 1 R 2 R 3 R 4 R 4 R 3
More informationChapter 8: Alkene Structure and Preparation via Elimination Reactions
1. Nature of the pi bond Chapter 8: Alkene Structure and Preparation via Elimination eactions [Sections: 8.1-8.13] C C bond length bond strength 3 C C 3 3 C C 3 3 C C 3 3 C 2 C C 2 3 C a C=C double bond
More informationAlkyl Halides. Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp 3 orbital of an alkyl group.
Alkyl Halides Alkyl halides are a class of compounds where a halogen atom or atoms are bound to an sp 3 orbital of an alkyl group. CHCl 3 (Chloroform: organic solvent) CF 2 Cl 2 (Freon-12: refrigerant
More informationOrganic Halogen Compounds
8 Organic alogen ompounds APTER SUMMARY 8.1 Introduction Although organic halogen compounds are rarely found in nature, they do have a variety of commercial applications including use as insecticides,
More informationHALOALKANES. Structure Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
aloalkanes AS3 1 ALOALKANES Structure ontain the functional group X where X is a halogen (F,l, or I) Types aloalkanes halogen is attached to an aliphatic skeleton alkyl group aloarenes halogen is attached
More informationc. Cl H Page 1 of 7 major P (E > Z and more substituted over less substituted alkene) LG must be axial are the same Cl -
CEM 109A 1. Predict the products of the following reactions (a-c E2, d-f E1 KEY focuses only on elimination products, in most cases there will also be substitution products.) a. - LG must be axial - are
More informationStructure and Preparation of Alkenes: Elimination Reactions
Structure and Preparation of Alkenes: Elimination Reactions Alkene Nomenclature First identify the longest continuous chain that includes the double bond. Replace the -ane ending of the corresponding unbranched
More informationChapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes
Additions to Alkenes Chapter 8 Alkenes and Alkynes II: Addition Reactions Generally the reaction is exothermic because one p and one s bond are converted to two s bonds Alkenes are electron rich The carbocation
More information1.13 Acid-Base Reactions: Lone-Pair Donors & Acceptors
1.13 Acid-Base Reactions: Lone-Pair Donors & Acceptors I, Cl, N 3, 3 P 4 pka 10 to 5 Super strong acids 3 + pka 1.7 RC 2 pka ~ 5 acids Ph pka ~ 10 get 2, R pka ~ 16 weaker RCC (alkynes) pka ~ 26 RN 2 pka
More informationChapter 5. Nucleophilic aliphatic substitution mechanism. by G.DEEPA
Chapter 5 Nucleophilic aliphatic substitution mechanism by G.DEEPA 1 Introduction The polarity of a carbon halogen bond leads to the carbon having a partial positive charge In alkyl halides this polarity
More informationOrganic Reactions Susbstitution S N. Dr. Sapna Gupta
Organic Reactions Susbstitution S N 2 Dr. Sapna Gupta Kinetics of Nucleophilic Reaction Rate law is order of reaction 0 order is when rate of reaction is unaffected by change in concentration of the reactants
More informationCHEM120 - ORGANIC CHEMISTRY WORKSHEET 1
EM120 - RGANI EMISTRY WRKSEET 1 Some of the objectives To understand and know the hybridization concept Be able to distinguish different geometries, including basic bond lengths and angles within organic
More informationC h a p t e r S e v e n : Haloalkanes: Nucleophilc Substitution and Elimination Reactions S N 2
C h a p t e r S e v e n : Haloalkanes: Nucleophilc Substitution and Elimination Reactions S N 2 CHM 321: Summary of Important Concepts Concepts for Chapter 7: Substitution Reactions I. Nomenclature of
More informationChapter 8 Alkenes and Alkynes II: Addition Reactions
Chapter 8 Alkenes and Alkynes II: Addition Reactions Introduction: Additions to Alkenes Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds The π electrons of
More information11. Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations
11. Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations Based on McMurry s Organic Chemistry, 6 th edition 2003 Ronald Kluger Department of Chemistry University of Toronto Alkyl Halides
More informationPAPER No. 5: REACTION MECHANISM MODULE No. 2: Types of Organic Reaction Mechanisms
Subject Chemistry Paper No and Title Module No and Title Module Tag Paper No. 5:Organic Chemistry-II Module No. 2: Overview of different types of Organic Reaction Mechanisms CHE_P5_M2 TABLE OF CONTENTS
More informationChapter 8: Chemistry of Alkynes (C n H 2n-2 )
hapter 8: hemistry of Alkynes ( n 2n-2 ) Bonding & hybridization Both are sp-hybridized Bond angles = 180 o 1 σ + 2 π bonds Linear around lassification R R R' σ bond energy: 88 kcal/mol π bond energy:
More informationChemistry 210 Organic Chemistry I Summer Semester 1999 Dr. Somnath Sarkar
Chemistry 210 Organic Chemistry I Summer Semester 1999 Dr. Somnath Sarkar Examination #3 Elimination Reactions Structure, Synthesis and Reactions of Alkenes and alkynes. Friday, July 23, 1999, 8:40 9:40
More informationCONCERTED sp 2 H. HO Et
Alkyl alides Substitution and Elimination 1 Substitutions (Quick Review) 1.1 SN2 Reactions LB nucleophile "backside attack!" NERTED reaction This is fundamentally just a Lewis acid/base reaction, the Lewis
More informationHomework problems Chapters 6 and Give the curved-arrow formalism for the following reaction: CH 3 OH + H 2 C CH +
omework problems hapters 6 and 7 1. Give the curved-arrow formalism for the following reaction: : 3 - : 2 : 3 2-3 3 2. In each of the following sets, arrange the compounds in order of decreasing pka and
More informationBSc. II 3 rd Semester. Submitted By Dr. Sangita Nohria Associate Professor PGGCG-11 Chandigarh 1
BSc. II 3 rd Semester Submitted By Dr. Sangita Nohria Associate Professor PGGCG-11 Chandigarh 1 Introduction to Alkyl Halides Alkyl halides are organic molecules containing a halogen atom bonded to an
More informationOrganic Chemistry Practice Problems: Solutions
rganic Chemistry Practice Problems: Solutions 1. 2. a. B, A b. D, B c. A, D d. D, A a. Resonance b. Electronegativity of fluorine atoms F F c. Neither is very acidic, but the oxygen will help stabilise
More information8.8 Unimolecular Nucleophilic Substitution S N 1
8.8 Unimolecular Nucleophilic Substitution S N 1 A question. Tertiary alkyl halides are very unreactive in substitutions that proceed by the S N 2 mechanism. Do they undergo nucleophilic substitution at
More informationChapter 8: Nucleophilic Substitution 8.1: Functional Group Transformation By Nucleophilic Substitution
hapter 8: Nucleophilic Substitution 8.1: Functional Group Transformation By Nucleophilic Substitution Nu: = l,, I Nu - Nucleophiles are Lewis bases (electron-pair donor) Nucleophiles are often negatively
More informationCycloalkanes: Common trimethylene tetramethylene Pentamethylene hexamethylene heptamethylene IUPAC name:
UNIT 3 YLALKANES, YLALKENES AND ALKADIENES: - - [5] Introduction: arbocyclic or homocyclic compounds resembling aliphatic compounds in their properties are called alicyclic compounds or cycloalkanes. ycloalkanes
More informationORGANIC CHEMISTRY. Chapter Cycloalkenes. Department of Chemistry, Xiamen University
ORGANI EMISTRY hapter 7 7.4 ycloalkenes Department of hemistry, Xiamen University ORGANI EMISTRY hapter 7 The rings of cycloalkenes containing five carbon atoms or fewer exist only in the cis form. yclopropene
More information1. Radical Substitution on Alkanes. 2. Radical Substitution with Alkenes. 3. Electrophilic Addition
1. Radical Substitution on Alkanes Only Cl and Br are useful at the laboratory level. Alkane reactivity: tertiary > secondary > primary > methyl Numbers below products give their relative yield. Relative
More informationREACTION AND SYNTHESIS REVIEW
REACTION AND SYNTHESIS REVIEW A STUDENT SHOULD BE ABLE TO PREDICT PRODUCTS, IDENTIFY REACTANTS, GIVE REACTION CONDITIONS, PROPOSE SYNTHESES, AND PROPOSE MECHANISMS (AS LISTED BELOW). REVIEW THE MECHANISM
More informationCHEM 2312 practice final. Version - II
EM 2312 practice final Version - II The following standardized final examination covers the entire introductory year of organic chemistry (EM 2311 and 2312 at Georgia Tech). The exam consists of 70 multiple
More informationAlcohols, Ethers, & Epoxides
Alcohols, Ethers, & Epoxides Alcohols Structure and Bonding Enols and Phenols Compounds having a hydroxy group on a sp 2 hybridized carbon enols and phenols undergo different reactions than alcohols. Chapter
More informationAlkenes. Dr. Munther A. M-Ali For 1 st Stage Setudents
Alkenes Dr. Munther A. M-Ali For 1 st Stage Setudents Alkenes Family of hydrocarbons, the alkenes, which contain less hydrogen, carbon for carbon, than the alkanes Structure of ethylene, The carbon-carbon
More informationChapter 9. Nucleophilic Substitution and ß-Elimination
Chapter 9 Nucleophilic Substitution and ß-Elimination Nucleophilic Substitution Nucleophile: From the Greek meaning nucleus loving. A molecule or ion that donates a pair of electrons to another atom or
More informationElimination Reactions. Chapter 6 1
Elimination Reactions Chapter 6 1 E1 Mechanism Step 1: halide ion leaves, forming a carbocation. Step 2: Base abstracts H + from adjacent carbon forming the double bond. Chapter 6 2 E1 Energy Diagram E1:
More informationWalden discovered a series of reactions that could interconvert (-)-malic acid and (+)-malic acid.
Chapter 11: Reactions of alkyl halides: nucleophilic substitutions and eliminations Alkyl halides are polarized in the C-X bond, making carbon δ+ (electrophilic). A nucleophilecan attack this carbon, displacing
More informationChapter 8: Alkene Structure and Preparation via Elimination Reactions
Nature of the pi bond Chapter 8: Alkene Structure and Preparation via Elimination eactions [Sections: 8.1-8.13] C C 3 C C 3 bond length bond strength 2 C C 2 a C=C double bond is stronger than a C C single
More informationCHEM 263 Oct 25, stronger base stronger acid weaker acid weaker base
CEM 263 ct 25, 2016 Reactions and Synthesis (Preparation) of R- Breaking the - Bond of R- with Metals R + Li 0 or Na 0 or K 0 metal R Li + 1/2 2 alkoxide Breaking the - Bond of R- by Acid-Base Reaction
More informationI. Multiple Choice Questions (Type-I)
Unit 13 HYDROCARBONS I. Multiple Choice Questions (Type-I) 1. Arrange the following in decreasing order of their boiling points. (A) n butane (B) 2 methylbutane (C) n-pentane (D) 2,2 dimethylpropane A
More informationEXPERIMENT 2 DEHYDRATION OF 1- & 2-BUTANOL & DEHYDROBROMINATION OF 1 & 2-BROMOBUTANE: ANALYSIS OF GASEOUS PRODUCTS BY GAS CHROMATOGRAPHY
EXPERIMENT 2 DEYDRATION OF 1- & 2-BUTANOL & DEYDROBROMINATION OF 1 & 2-BROMOBUTANE: ANALYSIS OF GASEOUS PRODUTS BY GAS ROMATOGRAPY A part of this procedure is adopted from an article published by.m. Gilow
More informationOrganic Chemistry CHM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl Halides: Substitution Reactions - Chapter 6 (Wade)
rganic Chemistry CM 314 Dr. Laurie S. Starkey, Cal Poly Pomona Alkyl alides: Substitution Reactions - Chapter 6 (Wade) Chapter utline I. Intro to RX (6-1 - 6-7) II. Substitution Reactions A) S N 2 (6-8,
More informationOrganic Chemistry Review: Topic 10 & Topic 20
Organic Structure Alkanes C C σ bond Mechanism Substitution (Incoming atom or group will displace an existing atom or group in a molecule) Examples Occurs with exposure to ultraviolet light or sunlight,
More information1-What is substitution reaction? 2-What are can Nucleophilic Substitution Reaction? 3- SN1 reaction. 4-SN2 reaction 5- mechanisms of SN1&SN2
1-What is substitution reaction? 2-What are can Nucleophilic Substitution eaction? 3- SN1 reaction. 4-SN2 reaction 5- mechanisms of SN1&SN2 1- SUBSTITUTION EACTIONS 1-Substitution eaction In this type
More informationLecture 20 Organic Chemistry 1
CEM 232 rganic Chemistry I at Chicago Lecture 20 rganic Chemistry 1 Professor Duncan Wardrop March 18, 2010 1 Self-Test Question Capnellene (4) is a marine natural product that was isolated from coral
More informationAlkenes. Alkenes-hydrocarbons with a carbon-carbon double bond. Alkenes have the formula C n H 2n. Nomenclature
Alkenes Alkenes-hydrocarbons with a carbon-carbon double bond. Alkenes have the formula n 2n. Nomenclature Alkenes are named in the same manner as alkanes with the following adjustments. 1. Find the longest
More informationREACTIONS: Elimination TECHNIQUES: Gas Chromatography
EM 51LB: EXPERIMENT 2 DEYDRATION OF 2-BUTANOL AND DEYDROBROMINATION OF 2-BROMOBUTANE: ANALYSIS OF GASEOUS PRODUTS BY GAS ROMATOGRAPY 1 WINTER 2012: TUESDAY, JANUARY 17 MONDAY, JANUARY 23 REATIONS: Elimination
More information10. Organohalides. Based on McMurry s Organic Chemistry, 7 th edition
10. Organohalides Based on McMurry s Organic Chemistry, 7 th edition What Is an Alkyl Halide An organic compound containing at least one carbonhalogen bond (C-X) X (F, Cl, Br, I) replaces H Can contain
More informationCHAPTER 8 HW SOLUTIONS: ELIMINATIONS REACTIONS
APTER 8 W SLUTNS: ELMNATNS REATNS S-TRANS SMERSM 1. Use a discussion and drawing of orbitals to help explain why it is generally easy to rotate around single bonds at room temperature, while it is difficult
More informationPAPER No. : 5; Organic Chemistry-II MODULE No. : 13; Mixed S N 1 and S N 2 Reactions
Subject Chemistry Paper No and Title Module No and Title Module Tag 5; Organic Chemistry-II 13; Mixed S N 1 and S N 2 Reactions CHE_P5_M13 TABLE OF CONTENTS 1. Learning Outcomes 2. Introduction 3. Nature
More information2/26/18. Practice Questions. Practice Questions B F. How many steps are there in this reaction?
Practice Questions Practice Questions D B F C E A G How many steps are there in this reaction? 1 Practice Questions D B F C E A G What is the highest-energy transitions state? Practice Questions D B F
More informationLecture 11 Organic Chemistry 1
EM 232 rganic hemistry I at hicago Lecture 11 rganic hemistry 1 Professor Duncan Wardrop February 16, 2010 1 Self Test Question What is the product(s) of the following reaction? 3 K( 3 ) 3 A 3 ( 3 ) 3
More informationEASTERN ARIZONA COLLEGE General Organic Chemistry I
EASTERN ARIZONA COLLEGE General Organic Chemistry I Course Design 2015-2016 Course Information Division Science Course Number CHM 235 (SUN# CHM 2235) Title General Organic Chemistry I Credits 4 Developed
More information8. What is the slow, rate-determining step, in the acidcatalyzed dehydration of 2-methyl-2-propanol?
CHEMISTRY 313-03 MIDTERM # 2 answer key October 25, 2011 Statistics: Average: 68 pts (68%); Highest: 100 pts (100%); Lowest: 30 pts (30%) Number of students performing at or above average: 56 (54%) Number
More informationDouble and Triple Bonds. The addition of an electrophile and a
Chapter 11 Additions to Carbon-Carbon Double and Triple Bonds The addition of an electrophile and a nucleophile to a C-C C double or triple bonds 11.1 The General Mechanism Pi electrons of the double bond
More informationDAV CENTENARY PUBLIC SCHOOL, PASCHIM ENCLAVE, NEW DELHI - 87
HYDROCARBONS 1. Why do alkenes prefer to undergo electrophilic addition reaction while arenes prefer electrophilic substitution reactions? Explain. 2. Alkynes on reduction with sodium in liquid ammonia
More informationTHE UNIVERSITY OF CALGARY FACULTY OF SCIENCE FINAL EXAMINATION CHEMISTRY 351 READ ALL THE INSTRUCTIONS CAREFULLY
hem 351 cont'd. Page 1 of 17 TE UIVERSITY F ALGARY FAULTY F SIEE FIAL EXAMIATI EMISTRY 351 DEEMBER 17th 2001 Time: 3 ours READ ALL TE ISTRUTIS AREFULLY PLEASE WRITE YUR AME, STUDET I.D. UMBER BT YUR EXAM
More informationStudy of Chemical Reactions
Study of Chemical Reactions Introduction to Mechanisms There are four different types of organic reactions: Additions Eliminations Substitutions Rearrangements 149 Addition Reactions Occur when 2 reactants
More informationReactions of Alkyl Halides with Nucleophiles and Bases a substitution reaction
Reactions of Alkyl Halides with Nucleophiles and Bases a substitution reaction Nucleophilic substitution and base induced elimination are among most widely occurring and versatile reaction types in organic
More information(Neither an oxidation or reduction: Addition or loss of H +, H 2 O, HX).
eactions of Alcohols Alcohols are versatile organic compounds since they undergo a wide variety of transformations the majority of which are either oxidation or reduction type reactions. xidation is a
More information1. CONCEPTS IN ORGANIC CHEMISTRY 2. SYNTHETIC ORGANIC CHEMISTRY 3. ISOMERISM II 4. HYDROCARBONS II 5. HALOALKANES. Vikasana - CET 2012
CET OBJECTIVE QUESTION ON 1. CONCEPTS IN ORGANIC CHEMISTRY 2. SYNTHETIC ORGANIC CHEMISTRY 3. ISOMERISM II 4. HYDROCARBONS II 5. HALOALKANES 1.The inductive effect a. Implies the atoms ability to cause
More informationChapter 8 Alkenes and Alkynes II: Addition Reactions. Alkenes are electron rich. Additions to Alkenes
Additions to Alkenes hapter 8 Alkenes and Alkynes II: Addition eactions Generally the reaction is exothermic because one π and one σ bond are converted to two σ bonds Alkenes are electron rich The carbocation
More informationReactions of Haloalkanes
Reactions of aloalkanes N Goalby chemrevise.org aloalkanes ontain a halogen atom covalently bonded to a carbon atom General formula: R-X where X is a halogen atom (F, l,, I) and R is the carbon chain.
More informationChemistry 2.5 AS WORKBOOK. Working to Excellence Working to Excellence
Chemistry 2.5 AS 91165 Demonstrate understanding of the properties of selected organic compounds WORKBOOK Working to Excellence Working to Excellence CONTENTS 1. Writing Excellence answers to Cis-Trans
More informationChapter 6. Polar addition and Elimination Reaction. RCH-CH2Br R C CH 2 H. open carbocation. Br -
hapter 6 Polar addition and Elimination eaction = 2 2 2 - -2 open carbocation - syn and anti products + + 17 kcal/mol Initial Protonation of the central carbon twisted structure and no allylic conjugation
More informationHALOGENOALKANES (HALOALKANES) Structure Contain the functional group C-X where X is a halogen (F,Cl,Br or I)
aloalkanes 2812 1 ALOGENOALKANES (ALOALKANES) Structure ontain the functional group X where X is a halogen (F,l, or I) Types alogenoalkanes halogen is attached to an aliphatic skeleton alkyl group aloarenes
More informationPhysical Properties: Structure:
Nomenclature: Functional group suffix = -ol Functional group prefix = hydroxy- Primary, secondary or tertiary? Alcohols are described as primary (1 o ), secondary (2 o ) or tertiary (3 o ) depending on
More information1. In the reaction shown above the nucleophile is. (a) Na (b) NaC CH (c) HC C (d) HC CH. 2. In the reaction shown above the nucleophile is
Chemistry 247B Hanson Sample Exam 4B In each case, read each possible answer, use a process of elimination, and circle the BEST answer. If you are having trouble deciding between two answers, briefly explain
More informationPoints: 1 / 15 / Total: 100 points /
Chemistry 6372 Fall 2002 omework #6 Answer Key Name Points: 1 / 15 / 2 / 10 / 3 / 10 / 4 / 10 / 5 / 10 / 6 / 10 / 7 / 35 / Total: 100 points / Average: 73 1) Answer the following questions from our book:
More informationuse iso-, tert-, sec- prefixes in your substituent names, where necessary
Chapter 07.2: 1 1) Name. Include E/Z stereochemistry in name, if necessary. a) 3 C b) c) d) e) f) use iso-, tert-, sec- prefixes in your substituent names, where necessary g) Do NT use iso-, tert-, sec-
More informationCHAPTER 9 THEORY OF RESONANCE BY, G.DEEPA
CHAPTER 9 THEORY OF RESONANCE BY, G.DEEPA Conjugation in Alkadienes and Allylic Systems conjugation a series of overlapping p orbitals The Allyl Group allylic position is the next to a double bond 1 allyl
More informationChapter 11, Part 1: Polar substitution reactions involving alkyl halides
hapter 11, Part 1: Polar substitution reactions involving alkyl halides Overview: The nature of alkyl halides and other groups with electrophilic sp 3 hybridized leads them to react with nucleophiles and
More informationCHEMISTRY MIDTERM # 2 October 27, The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck!
EMISTRY 313-01 MIDTERM # 2 ctober 27, 2005 Name... The total number of points in this midterm is 100. The total exam time is 120 min (2 h). Good luck! 1. (7 pts) Mark as true (T) or false (F) the following
More information