Preparation of 1-Bromobutane from 1-Butanol by Sn2 Reaction

2275 Words Aug 2nd, 2010 10 Pages
Name: Tonny, Chan Kar Yu, Student ID: 10297729
Date of Experiment: 19th March 2005, Group: B1
Title: Preparation of 1-bromobutane from 1-butanol by SN2 reaction
Objective:
1. To study the preparation of 1-bromobutane from 1-butanol by an SN2 reaction
2. To study the method of purification of an organic compound by simple extraction
3. To study the test of identification of alkyl halide

Chemicals and Apparatus:
~18.0 g 1-butanol, ~20.0 g sodium bromide, 15 ml of concentrated sulfuric acid, anhydrous magnesium sulfate, ~10 ml of 5% aqueous sodium bicarbonate, ~1 ml of sodium iodide – acetone reagent, 1 ml of bromine in chloroform, 1 piece of 100 cm3 round-bottomed flask, 1 piece of 50 cm3 of beaker, 1 piece of 50 cm3 of conical flask, 1
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10. The dry organic extract (1-bromobutane) was collected in a pre-weighed beaker and the exact mass of product was obtained.

C) Test for the product i) Sodium iodide in acetone test 1. 5 drops of the product (1-bromobutane) was placed to a test tube 2. A few drops of sodium iodide-acetone reagent were added to the test tube 3. The mixture was shaken and let it stand for 3 minutes. 4. Changes were observed. ii) Bromine test 1. 5 drops of the product (1-bromobutane) was placed to a test tube 2. A few drops of bromine-chloroform reagent were added to the test tube. 3. The mixture was shaken and let it stand for 3 minutes. 4. Changes were observed.

Results:
Preparation of 1-bromobutane from 1-butanol
Mass of 1-butanol used = 18.0 g

Mass of 1-bromobutane (dried) = 9.207 g

Percentage yield
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Observation during the course of reaction: two immiscible liquid formed, the one on the top is yellow colour, and the one on the bottom is colourless.

Purification of 1-bromobutane by extraction
Observation during the exaction: Two colourless layers formed, the yellow layer was decolourized, and the organic layer has glue-like smell.

Test for the product i) Sodium iodide in acetone test
Observation from the test: A small amount of white precipitate formed. ii) Bromine test
Observation from the test: Negative result, no observable change.
Discussion:
1. The purpose of this experiment was to prepare
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