Organic Chemistry Introduction PDF

INTRODUCTION OF ORGANIC CHEMISTRY HYDROCARBONS Assoc. Prof. Osama Farouk 1. Introduction Petroleum and coal are the major sources of various types of hydrocarbons. Hydrocarbons are the parent organic compounds, from which other organic compounds c...

INTRODUCTION OF ORGANIC CHEMISTRY HYDROCARBONS Assoc. Prof. Osama Farouk 1. Introduction Petroleum and coal are the major sources of various types of hydrocarbons. Hydrocarbons are the parent organic compounds, from which other organic compounds can be derived by replacing one or more hydrogen atoms with different functional groups. 2. Aliphatic Hydrocarbons Alkanes The general formula CnH2n+2 (n = number of carbon atoms). Alkane names always end with –ane, so the suffix is –ane Common system IUPAC Nomenclature Cyclic alkanes The general formula CnH2n METHODS OF PREPARATION 1- FROM UNSATURATED HYDROCARBONS 2- Reduction of Alcohols CH3CH2CH2CH2OH + HI CH3CH2CH2CH3 + I2 + H2O 3- From Carboxylic Acids i) Heating with soda lime: ii) Kolbe’s Electrolysis (for pot. Acetate): iii) By using Grignard’s Reagent dil.HCl (hydrolysis) CH3CH2MgBr C2H6 + Mg(OH)Br CH3CH2MgBr + CH3Br CH3CH2CH3 + MgBr2 (with alkyl halide) propane iv) Reduction of haloalkanes (alkyl Halides): v) Wurtz reaction: Chemical Properties of Alkanes Halogenation reactions: Chlorination of methane takes place via the free radical mechanism NITRATION REACTIONS:  Sulfonation reactions:  Unsaturated Hydrocarbons Alkenes (with double C=C bonds) the general formula CnH2n (n = number of carbon atoms). Cyclic alkenes the general formula CnH2n-2 Alkynes (with triple C≡C bonds) the general formula CnH2n-2 WRITE THE IUPAC NAME FOR CH2═CH─CH2─CH3 AND CH3─CH≡CH─CH3. STEP 1 NAME THE LONGEST CARBON CHAIN WITH A DOUBLE OF TRIPLE BOND: BUTENE, BUTYNE STEP 2 NUMBER THE CHAIN FROM THE END NEARER THE DOUBLE OR TRIPLE BOND: CH2═CH─CH2─CH3 1 2 3 4 CH3─CH≡CH─CH3 1 2 3 4 STEP 3 GIVE THE LOCATION AND NAME OF THE DOUBLE OR TRIPLE BOND. 1-BUTENE 2-BUTYNE WRITE THE IUPAC NAME FOR CH2═CH─CH2─CH3 AND CH3─CH≡CH─CH3. STEP 1 NAME THE LONGEST CARBON CHAIN WITH A DOUBLE OF TRIPLE BOND: BUTENE, BUTYNE STEP 2 NUMBER THE CHAIN FROM THE END NEARER THE DOUBLE OR TRIPLE BOND: CH2═CH─CH2─CH3 1 2 3 4 CH3─CH≡CH─CH3 1 2 3 4 STEP 3 GIVE THE LOCATION AND NAME OF THE DOUBLE OR TRIPLE BOND. 1-BUTENE 2-BUTYNE WRITE THE IUPAC NAME FOR STEP 1 NAME THE LONGEST CARBON CHAIN: PENTENE STEP 2 NUMBER THE CHAIN FROM THE END NEARER THE DOUBLE OR TRIPLE BOND: STEP 3 GIVE THE LOCATION AND NAME OF THE SUBSTITUENT AND DOUBLE OR TRIPLE BOND: 4-METHYL-2-PENTENE  WRITE THE IUPAC NAME FOR STEP 1 NAME THE LONGEST CARBON CHAIN: BUTYNE STEP 2 NUMBER THE CHAIN FROM THE TRIPLE BOND: STEP 3 GIVE THE LOCATION AND NAME OF THE SUBSTITUENT AND DOUBLE OR TRIPLE BOND: 3-METHYL-1-BUTYNE WRITE THE IUPAC NAME FOR EACH OF THE FOLLOWING: 1-butene 2-butene 2-methyl-2-butene 4-methyl-2-pentyne Draw the condensed structural formula for each of the following: A. 2-hexyne B. 3-methyl-3-hexene 3-methyl-4-octyne Preparation of alkenes 1. From Haloalkanes: Halaoalkanes are converted to alkenes by dehydrohalogenation. 2- From Dehalogenation of vicinal dihalides  3- Dehydration From Alcohols: Alkenes can be prepared from alcohols by dehydration in the presence of a suitable dehydrating agent such as (i) Al2O3 or (ii) concentrated H2SO4. 4- Kolbe’s Electrolysis (for pot. Succinate): 5- Hydrogenation of alkynes A Lindlar catalyst is a heterogeneous catalyst that consists of palladium deposited on calcium carbonate or barium sulfate which is then poisoned with various forms of lead or sulfur [Pd/CaCO3 or BaSO4 and (CH3COO)2Pb] Chemical Properties of Alkenes ⧫Addition Reactions: The chemical reactions in which a molecule adds to another molecule are called an addition reaction Addition of Hydrogen Addition of Halogens Addition of Halogen Acids (HX): Markonikoff's rule When an unsymmetrical reagent is added to an unsymmetrical alkene, the negative part of the reagent is attached to the unsaturated C atom having less number of hydrogen atoms. Thus, when HBr is added to propene, isopropyl bromide is obtained as major product  If the addition of HBr is carried out in the presence of peroxides such as benzoyl peroxide, then the reaction takes place contrary to Markownikoff’s rule. This is also known as Anti- Markownikoff’s addition or peroxide effect Addition of Water (hydration) [Markownikoff’s addition]  Addition of H2SO4 [Markownikoff’s addition]  Addition of halohydrine (hypohalose) Oxidation: The oxidation of alkenes can be done by using different oxidizing agents like KMnO4 and ozone. Oxidation with Ozone Preparation of alkynes ⧫ From Calcium Carbide Kolbe’s Electrolysis (for pot. maleate): Dehydrohalogenation of vicinal dihalides Chemical Properties of Alkynes Addition of Hydrogen  Addition of Halogens  Addition of Halogen Acids (HX) [Markownikoff’s addition]: Addition of Water (hydration) [Markownikoff’s addition]  Addition of H2SO4 [Markownikoff’s addition] Addition of halohydrine (hypohalose) Substitution reaction of alkenes THANK YOU