Separation of Acidic, Basic, and Neutral Compounds:
This is for an Ochem Lab. 1st-8th is just the steps of the procedure we followed and the question corresponds to the 8th step in the procedure;â In the first portion of the experiment, what is the purpose of washing the dichloromethane (layer C) with two 15 mL portions of water?
Background :
A mixture containing acidic, basic, and neutral compounds can be separated by acidic and basic properties. Commercial headache tablets, such as Excedrine, contain Aspirin (Acidic), Acetaminophen (Neutral), and Caffeine (Basic).
Procedure
1st)Weigh two headache tablets.
2nd)Crush using a mortal and pestle.
3rd)Dissolve the crushed tablets in 25mL of dichloromethane. Some solid binder may not dissolve so filter the dichloromethane using gravity filtration to remove the undissolved binder. This binder can be discarded.
4th)Transfer the dichloromethane solution to a separatory funnel and extract three times with 15 mL portions of 5% aqueous sodium bicarbonate.
5th)Combine the sodium bicarbonate layers in 100 mL beaker Labeled A.
6th)Extract the dichloromethane again but using three successive 15mL portions of 10% aqueous HCl.
7th)Combine the HCl layers in a beaker Labeled B.
8th)Lastly, wash* the dichloromethane with two 15mL portions of distilled water. The water will be the waste. Dry the dichloromethane over anhydrous calcium chloride. Label this C. 1.
Separation of Acidic, Basic, and Neutral Compounds:
This is for an Ochem Lab. 1st-8th is just the steps of the procedure we followed and the question corresponds to the 8th step in the procedure;â In the first portion of the experiment, what is the purpose of washing the dichloromethane (layer C) with two 15 mL portions of water?
Background :
A mixture containing acidic, basic, and neutral compounds can be separated by acidic and basic properties. Commercial headache tablets, such as Excedrine, contain Aspirin (Acidic), Acetaminophen (Neutral), and Caffeine (Basic).
Procedure
1st)Weigh two headache tablets.
2nd)Crush using a mortal and pestle.
3rd)Dissolve the crushed tablets in 25mL of dichloromethane. Some solid binder may not dissolve so filter the dichloromethane using gravity filtration to remove the undissolved binder. This binder can be discarded.
4th)Transfer the dichloromethane solution to a separatory funnel and extract three times with 15 mL portions of 5% aqueous sodium bicarbonate.
5th)Combine the sodium bicarbonate layers in 100 mL beaker Labeled A.
6th)Extract the dichloromethane again but using three successive 15mL portions of 10% aqueous HCl.
7th)Combine the HCl layers in a beaker Labeled B.
8th)Lastly, wash* the dichloromethane with two 15mL portions of distilled water. The water will be the waste. Dry the dichloromethane over anhydrous calcium chloride. Label this C. 1.
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