Sn2 Reaction 1-Bromobutane Lab Report
Lab 5: The SN2 Reaction: 1-Bromobutane
From K. L. Williamson, Macroscale and Microscale Organic Experiments, 2nd Ed. 1994, Houghton Mifflin, Boston. p247; revised 2/22/02
Prelab Exercise: Write a detailed flow sheet/ flow chart for the isolation and purification of 1-bromobutane. Designate how each minor-product is removed from the major product and which layer holds the product in each experimental step performed.
[pic]
Introduction
This experiment utilizes SN2 chemistry to convert 1-butanol (n-butanol) to 1-bromobutane (n-bromobutane). The nucleophile for the reaction is Br- ions. The nucleophile in this lab is generated from an aqueous solution of sodium bromide. The sulfuric acid acts as a catalyst in converting …show more content…
As time proceeds you should see the formation of your product as a separate layer on top of the aqueous layer. After the 45 minutes of reflux, distill (simple distillation) the product (from ~60-95 0C) into a large test-tube until no more water-insoluble droplets are seen to collect in the test-tube. One lab partner should wash the round-bottomed flask and the distillation apparatus as soon as the distillation is done and the apparatus has cooled down.
The other lab partner should move the distillate to a small disposable test-tube. Rinse the larger test-tube with about 1mL of water and transfer it to the same small disposable test-tube containing your product. Note that the 1-bromobutane now forms the lower layer.
Remove the 1-bromobutane from above, with a plastic pipette, and place it in another dry small test-tube. Add 1mL of concentrated sulfuric acid, and mix the contents well by flicking the tube. The acid will remove unreacted starting material and any …show more content…
Wash the 1-bromobutane layer (density 1.275 g/mL) with 1mL of 3 M NaOH (density 1.11 g/mL). NaOH neutralizes any traces of H2SO4 in the organic product layer. At this point, your product layer will turn milky. Let the two layers separate out and remove the top NaOH layer with a new plastic pipette. Please save all layers until you are absolutely sure that you have the product in hand.
Dry 1-bromobutane (product) by adding a small amount of anhydrous magnesium sulfate and mixing (glass rod) until the liquid clears. After 5 min, pour out the dried liquid into clean, dry and pre-weighed flask. Weigh the final product. Show your limiting reagent and calculate the theoretical yield and determine your percent yield (You need to show all work to get any credit!).
Your last step is to get the IR of your product and the IR of the starting material. This is important since it will give you proof that you manufactured the proper product. Your TA will show you how to use this instrument, especially for the first time. Analysis of the spectra should show a change from reactant to product. What functional group changes did you predict and did you actually
From K. L. Williamson, Macroscale and Microscale Organic Experiments, 2nd Ed. 1994, Houghton Mifflin, Boston. p247; revised 2/22/02
Prelab Exercise: Write a detailed flow sheet/ flow chart for the isolation and purification of 1-bromobutane. Designate how each minor-product is removed from the major product and which layer holds the product in each experimental step performed.
[pic]
Introduction
This experiment utilizes SN2 chemistry to convert 1-butanol (n-butanol) to 1-bromobutane (n-bromobutane). The nucleophile for the reaction is Br- ions. The nucleophile in this lab is generated from an aqueous solution of sodium bromide. The sulfuric acid acts as a catalyst in converting …show more content…
As time proceeds you should see the formation of your product as a separate layer on top of the aqueous layer. After the 45 minutes of reflux, distill (simple distillation) the product (from ~60-95 0C) into a large test-tube until no more water-insoluble droplets are seen to collect in the test-tube. One lab partner should wash the round-bottomed flask and the distillation apparatus as soon as the distillation is done and the apparatus has cooled down.
The other lab partner should move the distillate to a small disposable test-tube. Rinse the larger test-tube with about 1mL of water and transfer it to the same small disposable test-tube containing your product. Note that the 1-bromobutane now forms the lower layer.
Remove the 1-bromobutane from above, with a plastic pipette, and place it in another dry small test-tube. Add 1mL of concentrated sulfuric acid, and mix the contents well by flicking the tube. The acid will remove unreacted starting material and any …show more content…
Wash the 1-bromobutane layer (density 1.275 g/mL) with 1mL of 3 M NaOH (density 1.11 g/mL). NaOH neutralizes any traces of H2SO4 in the organic product layer. At this point, your product layer will turn milky. Let the two layers separate out and remove the top NaOH layer with a new plastic pipette. Please save all layers until you are absolutely sure that you have the product in hand.
Dry 1-bromobutane (product) by adding a small amount of anhydrous magnesium sulfate and mixing (glass rod) until the liquid clears. After 5 min, pour out the dried liquid into clean, dry and pre-weighed flask. Weigh the final product. Show your limiting reagent and calculate the theoretical yield and determine your percent yield (You need to show all work to get any credit!).
Your last step is to get the IR of your product and the IR of the starting material. This is important since it will give you proof that you manufactured the proper product. Your TA will show you how to use this instrument, especially for the first time. Analysis of the spectra should show a change from reactant to product. What functional group changes did you predict and did you actually