The SN2 Reaction: 1-Bromobutane
In this experiment, an SN2 reaction was utilized to synthesize 1-bromobutane (n-bromobutane) from 1-butanol (n-butanol). To obtain this reaction, sulfuric acid was added to a sodium bromide and 1-butanol solution to create hydrobromic acid. Upon heating, the alcohol reacted with the hydrobromic acid to create the alkyl bromide 1-bromobutane. Impurities of the bromobutane were then further removed through steam distillation, the addition and removal of both sulfuric acid an aqueous base, the product dried over calcium chloride, and finally fractionally distilled to render a pure sample of 1-bromobutane. The final sample product weighed 1.886 g, and the percent yield was determined to be 0.0138 moles.
An SN2 reaction is defined as a type of nucleophilic substitution where a lone pair from a nucleophile attacks an electron deficient electrophilic center and bonds to it. Doing so expels another group, known as the leaving group, thereby replacing the leaving group in one step.
experiment utilizes SN2 chemistry to convert 1-butanol (n-butanol) to 1-bromobutane (n-bromobutane). The nucleophile for the reaction is Br- ions. The nucleophile in this lab is generated from an aqueous solution of sodium bromide. The sulfuric acid acts as a catalyst in converting the OH functional group of butanol, to a better leaving group (water).
The by-products for this lab are 1-butene, di-n-butyl ether, and the starting alcohol (butanol). Any by-products are removed by extraction using concentrated sulfuric acid. The product can be removed from sulfuric acid, since it does not mix with H2SO4 and will remain as a separate layer.
|Chemical Name |Molecular Weight|Chemical Formula |Boiling Point|Safety Hazards |
|Acetone |58.08 |(CH3)2CO |56.5°C |Extremely flammable....