厦门大学化学化工学院：《有机化学》课程教学资源（课件讲稿，双语版）Chapter 3 An Introduction to Organic Reactions：Acids and Bases（3.2-3.7）Acid-Base Reactions

ORGANIC CHEMISTRY Chapter 3 3.2 Acid-Base Reactions Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.2 Acid-Base Reactions

ORGANIC CHEMISTRY Chapter 3 3.2A The Bronsted-Lowry Definition of Acids and bases o An acid is a substance that can donate(or lose )a proton, o a base is a substance that can accept (or remove a proton Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.2A The Brønsted-Lowry Definition of Acids and Bases An acid is a substance that can donate (or lose) a proton, A base is a substance that can accept (or remove) a proton

ORGANIC CHEMISTRY Chapter 3 3.2B The Lewis definition of acids and Bases g acids be defined as electron-pair acceptors o bases be defined as electron-pair donors Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.2B The Lewis Definition of Acids and Bases Acids be defined as electron-pair acceptors Bases be defined as electron-pair donors

ORGANIC CHEMISTRY Chapter 3 3.3 Heterolysis of Bonds to Carbon Carbocations and carbanions 碳正离子和碳负离子 Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.3 Heterolysis of Bonds to Carbon: Carbocations and Carbanions 碳正离子和碳负离子

ORGANIC CHEMISTRY Chapter 3 o Carbocation -an ion with a positive charge on the carbon atom o Carbanion -an ion with a negatively charged carbon atom C—C heterolysis C++ c Carbocation base -H C一H C heterolysis Carbanion Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 Carbocation — an ion with a positive charge on the carbon atom. Carbanion — an ion with a negatively charged carbon atom. C Cl δ δ heterolysis C + Cl Carbocation C H δ δ base C Carbanion H heterolysis

ORGANIC CHEMISTRY Chapter 3 o Carbocations are electron deficient. The have only six electron in their valence shell, and because of this carbocations are lewis acids o Carbocations occur as intermediates in some organic reactions o Carbocations react rapidly with Lewis bases C C-B Carbocation anion (a lewis acid )(a lewis base) A electrophile A nucleophile Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 Carbocations are electron deficient. The have only six electron in their valence shell, and because of this carbocations are Lewis acids. Carbocations occur as intermediates in some organic reactions. Carbocations react rapidly with Lewis bases. C + B Carbocation C B (a Lewis acid) anion (a Lewis base) A electrophile A nucleophile

ORGANIC CHEMISTRY Chapter 3 o Carbanions are lewis bases Nucleophile C + H-A C-H + A Carbanion Lewis acid (a lewis base C-+—C—L C—C +-L Carbanion Lewis acid a Lewis base Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 Carbanions are Lewis bases. Nucleophile C + Carbanion C H Lewis acid (a Lewis base) H Aδ δ + A C + Carbanion C Lewis acid (a Lewis base) L δ δ C L C +

ORGANIC CHEMISTRY Chapter 3 3. 4 The Use of curved arrows in Illustrating Reactions Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.4 The Use of Curved Arrows in Illustrating Reactions

ORGANIC CHEMISTRY Chapter 3 g a curved arrow is used to show the direction of electron flow in a reaction o The curved arrow begins with a covalent bond or unshared pair of higher electron density Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 A curved arrow is used to show the direction of electron flow in a reaction The curved arrow begins with a covalent bond or unshared pair of higher electron density

ORGANIC CHEMISTRY Chapter 3 3.5 The Strength of Acids and Bases Ka and pKa 3.6 Predicting The Outcome of Acid-Base Reactions Department of Chemistry, Xiamen University

ORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 3 3.5 The Strength of Acids and Bases: Ka and pKa 3.6 Predicting The Outcome of Acid-Base Reactions