Chemistry · Ch 12 — Aldehydes, Ketones and Carboxylic Acids
Trivial and IUPAC names of ketones
Trivial and IUPAC names of ketones
TRIVIAL NAMES of aliphatic ketones are built from the names of the two alkyl or aryl groups attached to the carbonyl carbon, written out in ALPHABETICAL order and followed by the word 'ketone' (e.g. ethyl methyl ketone). Where a substituent's position needs to be shown on a substituted aliphatic ketone, it too is labelled by Greek letters -- alpha for the carbon adjacent to the carbonyl carbon, beta for the next one, exactly as for aldehydes/acids in 12.3.1. Trivial names of AROMATIC ketones are instead based on the ending '-phenone' (e.g. acetophenone, benzophenone). IUPAC NAMES of aliphatic ketones are built from the name of the corresponding alkane by replacing its final '-e' with '-one' -- family name 'alkanone'. The longest carbon chain that contains the ketonic carbonyl group is numbered starting from whichever END is closer to the carbonyl carbon (unlike aldehydes/acids, a ketone's carbonyl carbon is not forced to be C1, since it need not sit at a chain end). Where TWO >C=O groups are present in the same molecule, the alkane's final '-e' is RETAINED and the suffix '-dione' is added, with both carbonyl carbons' locants cited. In a polyfunctional molecule where the ketonic carbonyl turns out to be the LOWER-priority functional group present, it is instead named as th …
Table 12.2 lists 11 ketones by structure, trivial name and IUPAC name: (1) CH3-CO-CH3, Dimethyl ketone (Acetone), Propanone. (2) CH3-CO-CH2-CH3, Ethyl methyl ketone, Butanone. (3) CH3-CO-CH2-CH2-CH3, Methyl n-propyl ketone, Pentan-2-one. (4) CH3-CH2-CO-CH2-CH3, Diethyl ketone, Pentan-3-one. (5) CH3-CHBr-CO-CH2-CH2-CH3, alpha-Bromoethyl n-propyl ketone, 2-Bromohexan-3-one. (6) (CH3)2C=CH-CO-CH3, Mesityl oxide, 4-Methylpent-3-en-2-one. (7) CH3-CO-CH2-CO-CH2-CH3, no trivial name given, Hexane-2,4-dione. (8) CH3-CO-CH2-CHO, no trivial name given, 3-Oxobutanal. (9) C6H5-CO-C6H5, Diphenyl ketone (Benzophenone), Benzophenone. (10) C6H5-CO-CH3, Methyl phenyl ketone (Acetophenone), Ace …
Worked out. A 'Do you know?' aside noting that carboxylic-acid trivial names often derive from the Latin name of their original natural source: formic acid from Formica (ant, since it is obtained from red ants), acetic acid from acetum (vinegar), propionic acid from propion (first fat, since it is a basic fat derivative), and butyric acid from butyrum (butter, its natural source) …