n-Butyl Bromide Preparation
The purpose of this lab is to properly extract and distill n-butyl bromide It is ideal to perform this technique with accuracy, which can be measured by the percent yield. Chemicals:
n-Butyl Bromide- clear, yellow liquid that is slightly soluble in water. Molar weight of 137.02g and has zero reactivity.
Sodium Bromide- white, crystals, granules. Soluble in water with no reactivity. Molar weight of 102.89g.
Sulfuric Acid- colorless liquid that is miscible in water and produces heat. Highly reactive and has molar weight of 98.08g.
Sodium Bicarbonate- baking soda, white lumps that are soluble in water. Zero reactivity and has molar weight of 84.01g.
Water- polar with molar weight of 18.02g
Weigh out 1.4mL of n-butyl alcohol in a round bottom flask.
Add 2.4g of sodium bromide and 2.4mL of water.
Cool mixture and slowly add 2.0mL of concentrated sulfuric acid using pipet. Assemble the reflux apparatus shown in the book and heat the mixture to gentle boil for 60 min while stirring. Remove from heat and remove as much as the bottom layer using pipet, should be aqueous. Add drop of water to aqueous solution that you plan to discard. Make sure water dissolves then discard.
Add 2mL 9M H2SO4 to remaining solution and shake.
Again, remove the aqueous layer on bottom and discard.
Add 2mL of water to solution and shake.
Organic layer on bottom, transfer bottom layer to clean 5mL vial. Add saturated aqueous sodium bicarbonate a little at a time while stirring. Shake and allow layers to separate.
Transfer lower alkyl halide layer in 3mL concial vial using pipet. Dry solution over anhydrous sodium sulfate.
Distill dry solution using Hickmann still.
When distillation complete, weigh the vial and calculate percent yield. Determine the infared spectrum of product using salt plate.
First I weighed an empty 10mL flask with lid = 15.887g. Then I added the n-butyl alcohol...
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