Grabber Reaction - HCl, Butanol, Acetone reaction – Outline with videos

HCl, Butanol, Acetone reaction – Outline with videos

Safety
Normal lab safety procedures should be followed at all times.

Reaction Preparation
1 – Turn on the block heater (70oC)

2 – Weigh out the samples in duplicate or triplicate (8-10mg per sample)
Use the screw cap test tubes with the cap and removable septa. The septa are made of silicone rubber with a thin layer of PTFE on one side, this PTFE side should be the one in contact with the reaction mixture. 

 

 

3 – Make up the reagent, you may need extra reagent to act as diluent so make up 100 ml more than necessary.

For 200 ml use…
300mg ammonium ferric sulphate (dodecahydrate) - NB Ferric not Ferrous
6.6 ml water
10.0 ml 12M HCl
84 ml butan-1-ol
100 ml acetone

For 300 ml use…
450mg ammonium ferric sulphate (dodecahydrate) - NB Ferric not Ferrous
9.9 ml water
15.0 ml 12M HCl
126 ml butan-1-ol
150 ml acetone

For 400 ml use…
600mg ammonium ferric sulphate (dodecahydrate) - NB Ferric not Ferrous
13.2 ml water
20.0 ml 12M HCl
168 ml butan-1-ol
200 ml acetone

4 – Add 10 ml of reagent to each tube (3x3.333 ml, reverse pipette)

 

5 – Transfer the tubes to the block heater and leave for 2.5 hours.
It is important that these tubes are not in direct sunlight, if in doubt cover the block heater to exclude light.

 

6 – Remove from the heating block and allow to cool. IMPORTANT - do not open these tubes while they are still warm as they may be under significant pressure.

 

7 – Measure the samples on a Spectrophotometer (e.g. Jasco V-530), recording the uv max and the absorbance value at this wavelength. The samples may need diluting (with the extra reagent) to get them below 1 absorbance unit (AU). The ideal is to dilute the samples so they are in the 0.4 to 0.8 AU range.

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