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

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

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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 piece of 250 cm3 of separating funnel, 1 piece of 10 cm3 of measuring cylinder, 1 piece of electronic hot plate, oil bath, several pieces of anti-bumping granules, ice, filter paper and filter funnel.

Background:
Nucleophilic substitution is an important class of organic reaction. In the experiment, 1-bromobutane was synthesized through the second order mechanism in the present of concentrated sulphuric acid and sodium bromide. The nucleophile in the experiment is bromide ion (Br-) while the leaving group is water.

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Purification of the product was then obtained by extraction. The principle of extraction as a purification method was based on the difference in solubility between impurities and product.

Identify of the product (1-bromobutane) can be confirmed by carrying out sodium iodide in acetone test. The test involves displacement of bromide by iodide. Since iodide is strong nucleophile which can displace the bromide ion from attached carbon. The reaction was carried out in acetone since acetone dissolved NaI, but not the products NaBr. So the appearance of precipitate and the time it takes to form is the basis for a qualitative test for alkyl halides. Procedures:

The experiment was divided into three...