Chemistry Reference
In-Depth Information
FIGURE 2.13
Structural differences between aldehydes and ketones.
Aldehydes and ketones have carbonyl carbon atoms with nominal oxidation
numbers of +1 and +2. Because of this, the properties of these classes depend
mainly on the carbonyl group. Any further difference between aldehydes and
ketones is because of the different number of carbon attachments on the
carbonyl carbon. As shown in
Figure 2.13
, the overall inductive effect on the car-
bonyl group in the two compound classes is different. Because this determines
how polar the carbonyl bond is, it affects the chemical reactivity of the group.
Table 2.13
Selected Aldehydes and Ketones
Formula
Common Name
IUPAC Name
B.P. (°C)
HCHO
Formaldehyde
Methanal
−21
CH
3
CHO
Acetaldehyde
Ethanal
21
CH
3
CH
2
CHO
Propionaldehyde
Propanal
49
CH
3
(CH
2
)
2
CHO
Butyraldehyde
Butanal
76
CH
2
]
CHCHO
Acrolein
Propenal
53
CH
3
CH
]
CHCHO
Crotonaldehyde
2-Butenal
104
Formylcyclohexane
Cyclohexanecarbaldehyde
161
Benzaldehyde
Benzaldehyde
178
CH
3
CO·CH
3
Acetone
Propanone
56
CH
3
CO·CH
2
CH
3
Ethyl methyl ketone
Butanone
80
CH
3
CH
2
CO·CH
2
CH
3
Diethyl ketone
3-Pentanone
102
-
Cyclohexanone
155
Methyl phenyl ketone
Acetophenone
202
IUPAC, International Union of Pure and Applied Chemistry.
2.8.1.1 NAMING
For convenience, aldehydes are often written in the short form as R-CHO and
ketones as R-CO-R′. General substitutive naming is done by replacing the -e of
the parent chain with -al (aldehydes) and -one (ketones).
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