1. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Chapter 11 Unsaturated Hydrocarbons 11.3 Addition Reactions 1

2. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Addition Reactions In alkene and alkynes, the double or triple bond is easily broken, providing electrons to form new bonds double and triple bonds are very reactive in addition reactions, reactants are added to the carbon atoms in the double or triple bond 2

3. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Hydrogenation In hydrogenation, hydrogen atoms add to the carbon atoms of a double bond or triple bond a catalyst such as Pt or Ni is used to speed up the reaction 3

4. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Hydrogenation of Oils Adding H 2 to double bonds in vegetable oils produces compounds with higher melting points solids at room temperature, such as margarine, soft margarine, and shortening 4

5. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check Write an equation for the hydrogenation of 1-butene using a platinum catalyst. 5

6. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution Write an equation for the hydrogenation of 1-butene using a platinum catalyst. Pt CH 2 =CH  CH 2  CH 3 + H 2 CH 3  CH 2  CH 2  CH 3 6

7. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Trans Fats The process of hydrogenation is used commercially to convert the double bonds in the unsaturated fats in vegetable oils to saturated fats such as margarine, which are more solid. Adjusting the amount of added hydrogen produces partially hydrogenated fats such as soft margarine, solid margarine in sticks, and shortenings, which are used in cooking. 7

8. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check Write the product of each the following: Pt CH 3  CH=CH  CH 3 + H 2 Pt + H 2 8

9. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution Write the product of each the following: Pt CH 3  CH=CH  CH 3 + H 2 CH 3  CH 2  CH 2  CH 3 Pt + H 2 9

10. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Halogenation Reactions In halogenation reactions, halogen atoms such as chlorine or bromine add across a double bond the reaction occurs without a catalyst a dihaloalkane product results In the general equation for halogenation, X 2 is used for either Cl 2 or Br 2. 10

11. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Halogenation Reactions The addition reaction of Br 2 across a double bond is used to test for the presence of double bonds. A positive result turns a clear solution red. 11

12. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Hydration In the addition reaction called hydration, an acid H + catalyst is required water (H−OH) adds to a double bond an H atom bonds to one C in the double bond an OH bonds to the other C an alkene is converted to an alcohol H OH H + CH 3  CH=CH  CH 3 + H  OH CH 3  CH  CH  CH 3 12

13. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Hydration When hydration occurs with a double bond that has an unequal number of H atoms, the H atom bonds to the C in the double bond with the more H the OH bonds to the C in the double bond with the fewer H atoms 13

14. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Learning Check Write the product for the hydration of each of the following. H + 1. CH 3  CH 2  CH=CH  CH 2  CH 3 + HOH CH 3 H + 2. CH 3  C=CH  CH 2  CH 3 + HOH H + 3. + HOH 14

15. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution Write the product for the hydration of each of the following. H + 1. CH 3  CH 2  CH=CH  CH 2  CH 3 + HOH H OH CH 3  CH 2  CH  CH  CH 2  CH 3 15

16. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution Write the product for the hydration of each of the following. CH 3 H + 2. CH 3  C=CH  CH 2  CH 3 + HOH CH 3 CH 3  C  CH  CH 2  CH 3 OH H 16

17. Chemistry: An Introduction to General, Organic, and Biological Chemistry, Eleventh Edition Copyright © 2012 by Pearson Education, Inc. Solution Write the product for the hydration of each of the following. H + 3. + HOH 17