SHORT NOTE Isolation of 3-Nitro-4-ethoxybenzaldehyde from a synthesis mixture

SHORT NOTE
061/2010
Sepacore™
Isolation of 3-Nitro-4-ethoxybenzaldehyde from a synthesis mixture
A. Talamona, BÜCHI Labortechnik AG
the main component. Therefore the solvent
gradient was modified by decreasing the content
of the more polar solvent (ethyl acetate) in the
first step.
TLC of the crude reaction mixture:
TLC on silica gel Si60F254, developed in
n-hexane/ethyl acetate 1:1, detection
UV 254nm
Second separation conditions
Eluent: n-hexane with 15 / 50 / 75% ethyl
acetate (%B), step gradient
CHO
Separation 2
NO2
O
CH3
Sepacore configuration
Cartridge 12 x 150mm, prepacked with silica
gel 60, 40 – 63 µm
2 Pump Modules C-605
Fraction Collector C-660
Control-Unit C-620 with SepacoreControl
software
UV Photometer C-635
First separation conditions
Eluent: n-hexane with 25 / 50 / 75% ethyl
acetate (%B), step gradient
Flow rate: 10ml/min
Sample: 0.5 g crude mixture, dissolved in
n-hexane/ethyl acetate 75:25
Injection volume: 1ml
TLC of the separated fractions
Silica gel 60F254, developed
in n-hexane/ethyl acetate
1:1, detection UV 254nm
Separation 1
100
Recovery
90
80
70
%
60
Abs.
50
= 25 mg, = 465 mg (= 3-Nitro-4ethoxybenzaldehyde), = 5 mg
%B
40
30
20
10
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
Time (min)
Under these conditions the impurity with the
shortest elution time cannot be separated from
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