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Aldehydes and Ketones. In an aldehyde, a carbon group and an H atom is attached to a carbonyl group O carbonyl group CH 3 - C - H carbonyl group always joined to at least one hydrogen (meaning it is always on the end!). Aldehydes and Ketones.
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Aldehydes and Ketones • In an aldehyde, a carbon group and an H atom is attached to a carbonyl group O carbonyl group CH3 - C -H carbonyl group always joined to at least one hydrogen (meaning it is always on the end!)
Aldehydes and Ketones • In a ketone, two carbon groups are attached to a carbonyl group O carbonyl group CH3- C -CH3 carbon of the carbonyl group is joined to two other carbons (meaning it is never on the end)
Naming Aldehydes • IUPAC Replace the -e in the alkane name with –al • Common Add aldehyde to the prefixes form (1C), acet (2C), propion(3), and butry(4C) OOO H-C-H CH3-C-H CH3CH2C-H methanal ethanal propanal (formaldehyde) (acetaldehyde) (propionaldehyde)
Methanal • common name: formaldehyde • 40% in water is formalin, a preservative
Naming Ketones • In the IUPAC name, the -e in the alkane name is replaced with -one • In the common name, add the wordketone after naming the alkyl groups attached to the carbonyl group OO CH3 -C-CH3 CH3-C-CH2-CH3 Propanone 2-Butanone (Dimethyl ketone) (Ethyl methyl ketone)
Propanone • Common name: acetone • nail-polish remover • miscible with water in all proportions
Ketones O O Butter flavor CH3-C-C-CH3 butanedione O Clove flavor CH3-C-CH2CH2CH2CH2CH3 2-heptanone
Aldehydes and Ketones • Neither can form intermolecular hydrogen bonds, thus a much lower b.p. than corresponding alcohols
Learning Check Classify each as an aldehyde (1), ketone (2) or neither(3). O A. CH3CH2CCH3 B. CH3-O-CH3 CH3 O C. CH3-C-CH2CH D. CH3
Solution Classify each as an aldehyde (1), ketone (2) or neither(3). O A. CH3CH2CCH3 2B. CH3-O-CH3 3 CH3 O C. CH3-C-CH2CH 1 D. 2 CH3
Learning Check Name the following O A. CH3CH2CCH3 B. CH3 O C. CH3-C-CH2CH CH3
Solution O A. CH3CH2CCH3 B. 2-butanone (ethyl methyl ketone) CH3 O C. CH3-C-CH2CH cyclohexanone CH3 3,3-dimethylbutanal
Learning Check Draw the structural formulas for each: A. 3-Methylpentanal B. 2,3-Dichloropropanal C. 3-Methyl-2-butanone
Solution Draw the structural formulas for each: CH3 O A. 3-Methylpentanal CH3CH2CHCH2CH Cl O B. 2,3-Dichloropropanal Cl-CH2CHCH O C. 3-Methyl-2-butanone CH3CHCCH3 CH3