1 Type of Organic Reactions Why? Many organic reactions lead to products we use everyday. Organic reactions can be categorized by looking at the reactants used and the products formed. Fragrances, flavors, and flames in your gas barbeque are all products of organic reactions. Learning Objectives • Recognize organic reactions: substitution, addition, elimination and rearrangment. • State the main types of organic reactions: ✓ substitution (nucleophilic, electrophilic and free radical) ✓ addition (electrophilic and nucleophilic) ✓ elimination ✓ rearrangement • Predict the type of organic reaction given a reaction equation. Success Criteria • Predict the products of organic reactions. • Name the type of organic reactions. Vocabulary • Substitution • Addition • Elimination • Rearrangment Prerequisites • Writing chemical equations • Ability to distinguish reactants and products in a reaction • Naming and identifying organic compounds • Ability to distinguishing between saturated and unsaturated hydrocarbons • Naming and recognizing functional groups in organic compounds
2 Free Radical Substitution Br2 /CH2 Cl2 uv CH3 CH3 CH3 CH2 Br + HBr Key Questions 1. What is/ are the reactant and product in this reaction? 2. Describe the substitution reaction. 3. What is the condition required for the reaction? Exercises 1. Draw and name the products of the substitution reaction between methane and bromine molecule. Br2 /CH2 Cl2 uv CH4 2. Describe the substitution reaction between methane and bromine molecule.
3 Electrophilic Aromatic Substitution H Br2 FeBr3 Br + HBr Key Questions 1. What is/ are the reactant and product in this reaction? 2. Describe the substitution reaction. 3. What is the condition required for the reaction? Exercises 1. Draw and name the products of the substitution reaction between benzene and chlorine molecule. H Cl2 FeCl3 2. Describe the substitution reaction between benzene and chlorine molecule.
4 Nuclephilic Substitution Reaction CH3CH2 Br + OH- (aq) CH3CH2OH + Brreflux (aq) Key Questions 1. What is/ are the reactant and product in this reaction? 2. Describe the substitution reaction. 3. What is the condition required for the reaction? Exercises 1. Draw and name the products of the substitution reaction between chloropropane and hydroxide ions. reflux CH3 CH2 CH2 Cl + OH- (aq) 2. Describe the substitution reaction between chloropropane and hydroxide ions.
5 + Cl Cl H2 C CH2 + Br Br ethene bromine H2 C CH2 Br Br 1,2-dibromoethane Electrophilic Addition Key Questions 1. What type of organic compound is the reactant in the addition reaction? 2. Describe the addition reaction. 3. Suggest at least two other diatomic molecules could replace bromine in an addition reaction. Exercises 1. Draw and name the products of the addition reaction between cyclobutane and chlorine. 2. Describe the addition reaction between cyclobutane and chlorine.
6 HC CH3 O + HCN CN HC CH3 OH methanal hydrogen cyanide hydroethanenitrile (cyanohydrin) H2SO4 C CH3 H3C O + KCN H2SO4 Nucleophilic Addition Key Questions 1. What type of organic compound is the reactant in the addition reaction? 2. Describe the addition reaction. 3. What are the characteristic features of an addition reaction? Exercises 1. Draw and name the products of the addition reaction between propanone and acidic potassium cyanide. 2. Describe the addition reaction between propanone and acidic potassium cyanide. 3. Describe an addition reaction in general terms.
7 C C H H H CH3 CH3 Br H2C C CH3 CH3 + HBr 2-bromo-2-methylpropane 2-methylpropene hydrogen bromide KOH, ethanol reflux OH KOH, ethanol reflux ELIMINATION Key Questions 1. What are the reactants and products in this reaction? 2. Describe elimination reaction. 3. What are the characteristic features of an elimination reaction? Exercises 1. Draw and name the products of the elimination reaction. 2. Describe the elimination reaction between cyclohexanol and alcoholic KOH. 3. Describe an elimination reaction in general terms.
8 Rearrangement Key Questions 1. Classify the carbocations. 2. State the type of reaction above. Exercises 1. State the type of reaction above. 2. Why is this reaction occur?