Chemistry

Chapter 18 ?2010, Prentice Hall Organic Chemistry, 7th Edition L. G. Wade, Jr. Ketones and Aldehydes Chapter 18 * Carbonyl Compounds Chapter 18 Chapter 18 * Carbonyl Structure Carbon is sp2 hybridized. C?O bond is shorter, stronger, and more polar than C?C bond in alkenes. Chapter 18 Chapter 18 * Ketone Nomenclature Number the chain so that carbonyl carbon has the lowest number. Replace the alkane -e with -one. 3-methyl-2-butanone 4-hydroxy-3-methyl-2-butanone C H 3 C O C H C H 3 C H 3 C H 3 C O C H C H 3 C H 2 O H 1 2 3 4 1 2 3 4 Chapter 18 Chapter 18 * Ketone Nomenclature (Continued) For cyclic ketones, the carbonyl carbon is assigned the number 1. 3-bromocyclohexanone O B r 1 3 Chapter 18 Chapter 18 * C H 3 C H 2 C H C H 3 C H 2 C H O Aldehydes Nomenclature

Chapter 15 ? 2010, Prentice Hall Organic Chemistry, 7th Edition L. G. Wade, Jr. Conjugated Systems, Orbital Symmetry, and Ultraviolet Spectroscopy Chaper 15 * Conjugated Systems Conjugated double bonds are separated by one single bond. Isolated double bonds are separated by two or more single bonds. Conjugated double bonds are more stable than isolated ones. Chaper 15 Chaper 15 * Heat of Hydrogenation of Conjugated Bonds For conjugated double bonds, the heat of hydrogenation is less than the sum for the individual double bonds. The more stable the compound, the less heat released during hydrogenation, Conjugated double bonds have extra stability. Chaper 15 Chaper 15 * Relative Stabilities twice 1-pentene more substituted Chaper 15 Chaper 15 * Structure of 1,3-Butadiene

Chapter 11 * Reaction with HBr ?OH of alcohol is protonated. ?OH2+ is good leaving group. 3? and 2? alcohols react with Br- via SN1. 1? alcohols react via SN2. H 3 O + B r - R O H R O H H R B r Chapter 11 Chapter 11 * Reaction with HCl Chloride is a weaker nucleophile than bromide. Add ZnCl2, which bonds strongly with ?OH, to promote the reaction. The chloride product is insoluble. Lucas test: ZnCl2 in concentrated HCl: 1? alcohols react slowly or not at all. 2? alcohols react in 1-5 minutes. 3? alcohols react in less than 1 minute. Chapter 11 Chapter 11 * SN2 Reaction with the Lucas Reagent Primary alcohols react with the Lucas reagent (HCl and ZnCl2) by the SN2 mechanism. Reaction is very slow. The reaction can take from several minutes to several days. Chapter 11 *

Chapter 12 * IR Spectrum of Amides Amides will show a strong absorption for the C?O at 1630?1660 cm-1. If there are hydrogens attached to the nitrogen of the amide, there will N?H absorptions at around 3300 cm-1. Chapter 12 * Carbon?Nitrogen Stretching C?N 1200 cm-1 C?N 1660 cm-1 usually strong C?N > 2200 cm-1 For comparison, C?C < 2200 cm-1 Chapter 12 Chapter 12 * IR Spectrum of Nitriles A carbon nitrogen triple bond has an intense and sharp absorption, centered at around 2200 to 2300 cm-1. Nitrile bonds are more polar than carbon?carbon triple bonds, so nitriles produce stronger absorptions than alkynes. Chapter 12 * Summary of IR Absorptions Chapter 12 Chapter 12 * Chapter 12 *

Chapter 12 ?2010, Prentice Hall Organic Chemistry, 7th Edition L. G. Wade, Jr. Infrared Spectroscopy and Mass Spectrometry Chapter 12 * Introduction Spectroscopy is a technique used to determine the structure of a compound. Most techniques are nondestructive (it destroys little or no sample). Absorption spectroscopy measures the amount of light absorbed by the sample as a function of wavelength. Chapter 12 Chapter 12 * Types of Spectroscopy Infrared (IR) spectroscopy measures the bond vibration frequencies in a molecule and is used to determine the functional group. Mass spectrometry (MS) fragments the molecule and measures their mass. MS can give the molecular weight of the compound and functional groups.