Alkyl Halide
Essay by review • February 4, 2011 • Lab Report • 3,071 Words (13 Pages) • 3,632 Views
Table of Contents Page
1. Aims 3
2. Preparation 3
2.1 Apparatus needed 3
2.2 Procedure 3
2.2.1 Preparation of Mixture 3
2.2.2 Carrying out Reflux 3
2.2.3 Carrying out Distillation 3
2.2.4 Washing 4
2.2.5 Further purification of 1-Bromobutane 4
3. Results 5
3.1 Molecular weight of 1-bromobutane 5
3.2 Theoretical yield of 1-bromobutane 5
3.3 Density and percentage yield of 1-bromobutane 5
4. Discussion 6
4.1 Brief overview 6
4.2 Balanced equations for reactions of 6
4.2.1 potassium bromide with sulphuric acid 6
4.2.2 hydrogen bromide with sulphuric acid 6
4.3 Mechanisms involved 6
4.3.1 Mechanism involved in 1-bromobutane formation 6
4.3.2 Possible side-products 7
4.3.3 Alternative method 7
4.4 Preparation of Mixture - Reasons for : 8
4.4.1 Why concentrated sulphuric acid was added 8
4.4.2 Why concentrated sulphuric acid needs to be cold 8
4.4.3 Why KBr needs to be finely powdered 8
4.5 Carrying out Reflux - Reasons for : 8
4.5.1 Why a heating mantle is used 8
4.5.2 Why the refluxing mixture has slight yellowish colouration 8
4.6 Carrying out Distillation - Reasons for : 8
4.6.1 Distillation at range of 99 - 103oC 8
4.7 Washing - Reasons for : 8
4.7.1 Washing with deionised water, then sulphuric acid, then sodium 9
hydrogencarbonate and finally deionised water
4.8 Further purification of 1-bromobutane - Reasons for : 9
4.8.1 Addition of anhydrous calcium chloride 9
4.9 Separation of layers 9
4.10 Possible errors that contribute to inaccuracy of yield 10
4.11 Precautions 10
5. Conclusion 10
6. References 10
6.1 Internet references 10
6.2 Book references 10
7. Appendix 11
7.1 Figures 11
1. Aims
The aims of this experiment is for the student to attempt questions in the 'Pre-Lab' section before the experiment, and to prepare a sample of 1-bromobutane using reflux and distillation, and then to determine the percent yield and density of 1-bromobutane.
2. Preparation
2.1 Apparatus
A 25-mL and a 100-mL round-bottom flask, separatory funnel, ice-water bath, apparatus for heating under reflux, simple distillation, magnetic stirring, and flameless heating.
2.2 Procedure
Chemical Equation:
CH3CH2CH2CH2OH + KBr + H2SO4 → CH3CH2CH2CH2Br + KHSO4 + H2O
2.2.1 Preparation of Mixture:
2.2.2 Carrying out Reflux:
2.2.3 Carrying out Distillation
2.2.4 Washing
2.2.5 Further purification of 1-bromobutane
3. Results
CH3CH2CH2CH2OH + KBr + H2SO4 → CH3CH2CH2CH2Br + KHSO4 + H2O
3.1 Molecular weight of 1-bromobutane
Molecular weight of 1-bromobutane = 4 (12.0) + 9 (1.01) + 79.9
= 137.0 g (3sf)
3.2 Theoretical yield of 1-bromobutane
According to the equation,
No. of moles of n-butyl alcohol = 0.25mol
= no. of moles of 1-bromobutane
Theoretical yield of 1-bromobutane = 0.25 mol X 137.0 g
= 34.25 g
3.3 Density and percentage yield of 1-bromobutane
Weight
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