1. Chapter 20 The Chemistry of Carboxylic Acids

2. Carboxylic Acids General structure: Characteristic functional group is called the carboxy group 2 20.1 Nomenclature of Carboxylic Acids

3. 3 Acetic acidButyric acidCaproic acid Palmitic acid

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5. Common Nomenclature Change the “-yl” (or “-oyl”) of the acyl group to “ic acid” 5 Acetyl group

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7. More Complicated Common Nomenclature Dicarboxylic acids 7 β-chlorovaleric acid

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9. IUPAC Nomenclature Replace the “-e” of the alkane name with “-oic acid” The carbonyl carbon is numbered as C1 For multiple carboxyl groups, retain the “-e” in the alkane name and insert a Greek prefix (di, tri etc.) between the “e” and “oic acid” 9

10. When a carboxyl group is bonded to a ring: 1)The ring carbon bonded to the –CO 2 H group is considered C1 2)The ending is “-carboxylic acid” 10

11. Problems 1)Name the following molecules using common nomenclature 2)Name the following molecules using IUPAC nomenclature 11

12. 3)Draw 1,2,4-benzenetricarboxylic acid 12

13. Structure and Physical Properties The carbonyl oxygen is the oxygen involved with the C=O double bond The carboxylate oxygen is the oxygen involved with the C-O single bond 13

14. Structure and Physical Properties Carboxylic acids have relatively high boiling points – Polarity – Hydrogen bonding Many are water soluble 14

15. IR Spectroscopy Carboxylic acids have two characteristics in IR spectroscopy that make them easy to identify – C=O stretch: 1710 cm -1 (as the dimer) – O-H stretch: 2400-3600 cm -1 (very broad) 15

16. NMR Spectroscopy O-H:  9-13 (broad) 16 20.3 Spectroscopy of Carboxylic Acids

17. Problem Compound X, C 4 H 8 O 3, has infrared absorptions at 1710 and 2500-3100 cm -1 and has the 1 H NMR spectrum shown below. Propose a structure for X. 17