Conversion of Alcohol to Alkyl Halides
Conversion of Alcohols to Alkyl Halides
Ankita Patel
August 6, 2013
Introduction This lab consisted of the conversion of alcohols into alkyl halides through common substitution methods. These methods include SN1 and SN2 mechanism, both of which can occur for this type of reaction. For both reactions, the first step of protonation will be to add hydrogen to the –OH group and then the rest of the reaction will proceed according to the type of mechanism. SN1 reactions form a cation intermediate once the H2O group leaves, then allowing a halide (such as Br) to attack the positively charged reagent1. On the other hand, SN2 reactions are one-step mechanism in which no intermediate is formed and the halide attaches as the leaving group detaches1. Rearrangements of the product are possible during the SN1 mechanisms, but not for SN2 mechanisms. This lab will examine the reaction of 1-propanol and 2-pentanol with NaBr in H2SO4, in which the H2O acts as the leaving group and Br as the attaching nucleophile (1). After the reaction has taken place through reflux and distillation, the product is able to be examined through NMR and IR spectroscopy analysis. Finally, these graphs will help in determining the products of each reaction and the type of mechanism used.
SN1:
SN2:
Mechanism of 1-propanol:
Mechanism of 2-pentanol:
Table of Reagents Compound | Molecular Weight | Boiling Point | Melting Point | Density | 1-propanol | 60.10 g/mol | 97 °C | -127 °C | 0.804 g/mL | 2-pentanol | 88.15 g/mol | 119 °C | -50 °C | 0.812 g/mL | NaBr | 102.89 g/mol | 1396 °C | 747 °C | 0.733 g/mL | H2SO4 | 98.08 g/mol | 337 °C | 10 °C | 1.84 g/mL | 1-bromopropane | 122.99 g/mol | 71 °C | -110 °C | 1.354 g/mL | 2-bromopropane | 122.99 g/mol | 59 °C | -90 °C | 1.31 g/mL | 2-bromopentane | 151.04 g/mol | 117 °C | -95 °C | 1.223g/mL | 3-bromopentane | 151.04 g/mol | 119 °C | -97 °C | 1.216 g/mL | NaHCO3 | 84.01 g/mol | decomposes | 60 °C | 2.2 g/mL |
Ankita Patel
August 6, 2013
Introduction This lab consisted of the conversion of alcohols into alkyl halides through common substitution methods. These methods include SN1 and SN2 mechanism, both of which can occur for this type of reaction. For both reactions, the first step of protonation will be to add hydrogen to the –OH group and then the rest of the reaction will proceed according to the type of mechanism. SN1 reactions form a cation intermediate once the H2O group leaves, then allowing a halide (such as Br) to attack the positively charged reagent1. On the other hand, SN2 reactions are one-step mechanism in which no intermediate is formed and the halide attaches as the leaving group detaches1. Rearrangements of the product are possible during the SN1 mechanisms, but not for SN2 mechanisms. This lab will examine the reaction of 1-propanol and 2-pentanol with NaBr in H2SO4, in which the H2O acts as the leaving group and Br as the attaching nucleophile (1). After the reaction has taken place through reflux and distillation, the product is able to be examined through NMR and IR spectroscopy analysis. Finally, these graphs will help in determining the products of each reaction and the type of mechanism used.
SN1:
SN2:
Mechanism of 1-propanol:
Mechanism of 2-pentanol:
Table of Reagents Compound | Molecular Weight | Boiling Point | Melting Point | Density | 1-propanol | 60.10 g/mol | 97 °C | -127 °C | 0.804 g/mL | 2-pentanol | 88.15 g/mol | 119 °C | -50 °C | 0.812 g/mL | NaBr | 102.89 g/mol | 1396 °C | 747 °C | 0.733 g/mL | H2SO4 | 98.08 g/mol | 337 °C | 10 °C | 1.84 g/mL | 1-bromopropane | 122.99 g/mol | 71 °C | -110 °C | 1.354 g/mL | 2-bromopropane | 122.99 g/mol | 59 °C | -90 °C | 1.31 g/mL | 2-bromopentane | 151.04 g/mol | 117 °C | -95 °C | 1.223g/mL | 3-bromopentane | 151.04 g/mol | 119 °C | -97 °C | 1.216 g/mL | NaHCO3 | 84.01 g/mol | decomposes | 60 °C | 2.2 g/mL |
References: Brown, William Henry, Christopher S. Foote, Brent L. Iverson, and Eric Anslyn. Organic Chemistry. Belmont, CA: Brooks/Cole Cengage Learning, 2009. Print. Hill, Richard K. and John Barbaro, Experiments in Organic Chemistry, 3rd Edition; Contempory Publishing Company of Raleigh Inc., 2005; T1-4, E2.