Jones Reagent
Jones reagent is prepared by dissolving chromium trioxide or potassium dichromate in concentrated sulfuric acid. The reagent is added to the test substance and diluted with acetone.
It is used to test for primary and secondary alcohols. A positive reaction will also be seen with aldehydes. Enols may also give a positive reaction. Tertiary alcohols do not react.
A positive reaction is characterized by a change in color from orange-yellow to green within 15 seconds. The green color is due to the formation of chromium sulfate precipitate.
Procedure
1. Dissolve 10 mg (solid) or 2 drops (liquid) of the unknown substance in 0.8 mL to 1 mL of pure acetone.
2. Add 1 drop of Jones reagent and shake.
3. Look for a color change from orange-yellow to green.
No comments:
Post a Comment