Synthesis of N-Butyl Bromide

CHEM 3719

JUNE 17 2013

SYNTHESIS OF n-BUTYL BROMIDE

Procedure:

Assemble reflux apparatus

Add 17 g of Sodium Bromide into a 100 mL round bottom flask

Add 17 mL of water and 10 mL of n-butyl alcohol to the flask

Place flask securely in an ice bath and add 14 mL of Sulfuric Acid while swirling

Add boiling stones to mixture

Place round bottom flask onto the heating mantle and begin to heat for 60-75 minutes

Remove from heat and allow to cool

Pour mixture into a 125 mL separatory funnel

Drain lower aqueous layer from the funnel and discard

Add 14 mL of 9M H2SO4 (Sulfuric Acid) to the funnel

Shake funnel, remember to open stopcock to release gas

Drain and discard lower aqueous layer

Add 14 mL of H2O to the funnel, and shake

Drain lower layer into a small beaker, and discard aqueous layer

Pour organic layer back into the funnel and slowly add 14 mL of saturated aqueous sodium bicarbonate

Shake funnel, and drain lower alkyl halide into a dry Erlenmeyer flask

Add 1 g of anhydrous calcium chloride and allow to dry

Assemble distillation apparatus

Transfer the dried alkyl halide into a dry 25 mL round bottom flask

Add boiling stone and begin distilling the crude n-butyl bromide

Discard first 3 drops, and collect drops between 94 and 102 degree celsius

Weigh the product and calculate the percent yield, and determine a microscale boiling point

Results:

First drop: 75 Degrees Celsius

Last drop: 87 Degrees Celsius

Recovered Amound: 3.05 g

1.

Reagent |Amount |mmol |bp (Celsius) observed | |Sodium Bromide |17 g |1.6522 |na | |1-Butanol |10 mL |1.349 |na | |Sulfuric Acid |14 mL |1.4285 |na | |1-Bromobutane |3.05 g |22.259 |78 | |

2. Percent Yield:

n-butyl bromide (MW = 137.03 g/mol, density = 1.27 g/ml)

10 ml of n-butyl alcohol (density = 0.81 g/mL, MW = 74.1 g/mol)

17 g of sodium bromide (MW = 102.90 g/mol)

10 mL 1-butanol x 0.810 g 1-butanol / 1 mL 1-butanol =

8.1 g 1-butanol

8.1...