Engineering Chemistry S Datta

516 ENGINEERING CHEMISTRY
Example 1.
Methyl-vinyl-ketone:
R
C=C—C=O
, -unsaturated ketone
CH 3
H
C=C—C=O
H
H
In this case, there is no α and β substituent. Here base value is 215 mµ and no additions
are required according to rule. So, the calculated λ max
value is 215 mµ. The observed value is
213 mµ.
Example 2.
2-Methyl-1-butene 3 one
CH 3
CH 3
H
H3C—C—C = CH
2 C=C—C=O
H
O
CH 3
Here, base value is 215 mµ,
For α-substituent +10 mµ is added.
Calculated λ max
value = 225 mµ.
The observed value is 220 mµ.
Example 3.
3-pentene-2-one.
H O
H H
H3C—HC = C—C—CH 3 CH—C=C—C=O
3
Here, base value is 215 mµ
There is no α substituent + 0 mµ
For one β substituent + 12 mµ
Calculated λ max
value = 227 mµ.
Observed λ max
value = 224 mµ.
Example 4.
3-Methyl-3 pentene-2 one.
CH 3
H CH 3 O H CH 3
H3C—C = C——C—CH 3 CH—C=C—C=O
3
CH 3