Organic Chemistry, 5th Edition L.G. Wade jr Chapter 14 Ethers, Epoxides and sulfides Jo blackburn Richland college, dallas TX Dallas County Community College District c 2003. Prentice hall
Chapter 14 Ethers, Epoxides, and Sulfides Jo Blackburn Richland College, Dallas, TX Dallas County Community College District © 2003, Prentice Hall Organic Chemistry, 5th Edition L. G. Wade, Jr
Introduction FormulaR-o-R where r is alkyl or ary Symmetrical or unsymmetrical Examples: CH3-O-CH3 〉O-CH > Chapter 14
Chapter 14 2 Introduction • Formula R-O-R where R is alkyl or aryl. • Symmetrical or unsymmetrical • Examples: O CH3 CH3 O CH3 O =>
Structure and polarity Bent molecular geometry Oxygen is sp hybridized Tetrahedral angle H H C 110 H H H H Chapter 14
Chapter 14 3 Structure and Polarity • Bent molecular geometry • Oxygen is sp3 hybridized • Tetrahedral angle =>
Boiling Points Similar to alkanes of comparable molecular weight TABLE 14- Comparison of the boiling points of Ethers. Alkanes, and Alcohols of Similar Molecular Weights Compound Formula Mw bp(C) Dipole Moment (D) water HO 18 100 1.9 ethanol CH3CH,-OH 46 1.7 dimethyl ether CH:-0-CH 46 25 propane CH CH2CH3 0.1 月- butanol CHa CH, CH- CH2-OH 74 118 1.7 tetrahydrofuran 72 66 diethyl ether CHaCH20--CH CH 7 pentane CH3CH,CH CH,CH3 36 0.1 Note: The alcohols are hydrogen bonded, giving them much higher boiling points. The et hers have boil ing points that are closer to those of alkanes with similar molecular weights Chapter 14
Chapter 14 4 Boiling Points Similar to alkanes of comparable molecular weight
Hydrogen Bond Acceptor Ethers cannot h-bond to each other Alcohol + ether In the presence of OH or-NH (donor), R the lone pair of O—H electrons from ether forms a hydrogen R R bond with the-oh or NH hydrogen bond donor acceptor Chapter 14
Chapter 14 5 Hydrogen Bond Acceptor • Ethers cannot H-bond to each other. • In the presence of -OH or -NH (donor), the lone pair of electrons from ether forms a hydrogen bond with the -OH or -NH. =>