lecture 16 - The Carbonyl Group Aldehydes Ketones Chapter...

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Aldehydes Aldehydes & & Ketones Ketones Chapter 16 Chapter 16 The Carbonyl Group The Carbonyl Group ± In this and several following chapters, we study the physical and chemical properties of classes of compounds containing the carbonyl group, C=O The Carbonyl Group the carbonyl group consists of one sigma bond formed by the overlap of sp 2 hybrid orbitals and one pi bond formed by the overlap of parallel 2 p orbitals pi bonding and pi antibonding MOs for formaldehyde Structure Structure the functional group of an aldehyde is a carbonyl group bonded to a H atom and a carbon atom or another hydrogen atom the functional group of a ketone is a carbonyl group bonded to two carbon atoms Ethanal (Acetaldehyde) Methanal (Formaldehyde) OO CH 3 HCH Propanone (Acetone) O 3 CCH 3 Nomenclature ± IUPAC names: the parent chain is the longest chain that contains the functional group for an aldehyde, change the suffix from -e to -al al for an unsaturated aldehyde, change the infix from -an an - to -en en - ; the location of the suffix determines the numbering pattern for a cyclic molecule in which -CHO is bonded to the ring, add the suffix - carbaldehyde Nomenclature: Nomenclature: Aldehydes Aldehydes
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Nomenclature: Aldehydes Nomenclature: Nomenclature: Aldehydes Aldehydes the IUPAC retains the common names benzaldehyde and cinnamaldehyde, as well formaldehyde and acetaldehyde CHO C 6 H 5 trans -3-Phenyl-2-propenal (Cinnamaldehyde) CH 2 O Formaldehyde CH 3 CHO Acetaldehyde Benzaldehyde Nomenclature: Ketones Ketones ± IUPAC names the parent alkane is the longest chain that contains the carbonyl group indicate the ketone by changing the suffix -e to -one one number the chain to give C=O the smaller number Nomenclature: Nomenclature: Ketones ± IUPAC names the IUPAC retains the common names acetone, acetophenone, and benzophenone 1-Phenyl-1-pentanone O Propanone (Acetone) O Acetophenone O Benzophenone O Examples Nomenclature Practice
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Nomenclature Practice (S)-3-ethyl-2-hydroxypentanal 3-methyl-2-cyclohexenone (2S,5R)-2-isopropyl-5-methylcyclohexanone For compounds that contain more than one functional group Common Names (aldehydes aldehydes ) for an aldehyde, the common name is derived from the common name of the corresponding carboxylic acid Common Names Common Names (ketones ketones ) for a ketone, name the two alkyl or aryl groups bonded to the carbonyl carbon and add the word ketone Ethyl isopropyl ketone Diethyl ketone Dicyclohexyl ketone O O O Physical Properties ± Oxygen is more electronegative than carbon (3.5 vs 2.5) and, therefore, a C=O group is polar Physical Properties Physical Properties ¾ aldehydes and ketones are polar compounds and interact in the pure state by dipole-dipole interaction ¾ they have higher boiling points and are more soluble in water than nonpolar compounds of comparable molecular weight
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Reaction Themes Reaction Themes ± One of the most common reaction themes of a carbonyl group is addition of a nucleophile to form a
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This note was uploaded on 09/06/2009 for the course CHEM chem 12 AB taught by Professor Valentin during the Spring '09 term at Evergreen Valley.

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lecture 16 - The Carbonyl Group Aldehydes Ketones Chapter...

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