Experiment 13: Synthesis of 1-Bromobutane An SN2 Reaction
Experiment #13: Synthesis of 1-Bromobutane an SN2 Reaction
Introduction: In order to synthesize 1-Bromobutane an alkyl halide must be present to undergo a nucleophilic substitution reaction of an alcohol. Since 1-butanol is a primary substrate it will undergo an SN2 reaction with sodium bromide in order to convert the alcohol group to water which is a better leaving group and will in the end produce 1-bromobutane. Experimentally the lab students will see the reaction take place using their knowledge from lecture class to justify why this reaction occurs. Purpose: In order for a safe and effective experiment the correct amounts of both the substrate and nucleophile must be measured out and mixed together in the presence of water in order for 1-bromobutane to be created. The lab students will have to use multiple different laboratory techniques in order to yield the final product being 1-bromobutane. This simple reaction shows how an SN2 reaction takes place and how an acid-mediated reaction can synthesize an alkyl halide from the original alcohol compound. Abstract: The sodium bromide being the nucleophile in the reaction was combined with water and 1-butanol allowing the reaction to complete. The flask was cooled with an ice bath to keep the reaction under control, and then sulfuric acid was added to the cold mixture. The sulfuric acid allowed for the metal in this case sodium to dissociate from the bromine atom allowing it to have a negative charge. The positive cation left on the carbon that lost the alcohol will be replaced by the bromine ion, creating 1-bromobutane. The lab students had to understand the basic separation techniques to conduct this lab safe and effectively. They had to setup a simple distillation to distill the mixture quickly once the reaction took place. The distillate then had to be transferred to a separatory funnel to further separate. By following the...
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