Short Note #62: Isolation of Benzylideneacetophenone

Buchi Sepacore Flash Chromatography System

Buchi Sepacore Flash Chromatography System

Review Short Note #62: Isolation of Benzylideneacetophenone from a Crude Reaction Mixture using the Buchi Sepacore Flash Chromatography system.

TLC of the Crude Reaction Mixture:
TLC on silica gel Si60(F254), developed in n-hexane/ethyl acetate 19:1, detection UV 254nm

Buchi Sepacore Configuration:
Cartridge 12 x 150mm, prepacked with silica gel 60, 40 – 63 μm
2 Pump Modules C-605
Fraction Collector C-660, UV Photometer C-635
Control-Unit C-620 with SepacoreControl software

Separation Conditions:
Eluent for Separation 1: n-hexane with 2% ethyl acetate, isocratic
Eluent for Separation 2: n-hexane with 1%, 2% und 3% ethyl acetate, step gradient. Each step was initiated after a component was completely eluted (at the end of a peak)

Flow rate: 10 ml/min 100 mg crude mixture, dissolved in n-hexan and some drops of toluene (solubility of the sample in pure n-hexane too low)
Loading: approx. 0.4 ml

Scale-Up:
Calculation of the scale-up factor
Cartridge 12 x 150mm: cross sectional area = 1.13 cm2
Cartridge 40 x 150mm: cross sectional area = 12.56 cm2
Scale-up-factor = 12.56 cm2 / 1.13 cm2 = 11.1 » 10

Separation Conditions:
Eluent: n-hexane with 1%, 2% and 3% ethyl acetate, step gradient.
Sample: 1 g crude mixture, dissolved in n-hexane/toluene 7:3 (solubility of the sample in n-hexane too low, toluene is eluted as front peak)
Injection volume: 2 ml

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