Pablo Miguel Barranco Fernando
Institute of Chemistry, University of the Philippines, Diliman, Quezon City 1101 Philippines
Date Performed: December 11 , 2012; Date Submitted: January 8, 2013
Abstract: Alkyl halides can be synthesized from alcohols through its reaction with strong acids acting as hydrogen halides, HX (X = Cl, Br, I). The mechanisms of acid-catalyzed substitution of alcohols can be classified as either SN1 or SN2, where SN stands for nucleophilic subsitution and 1 or 2 designating its molecularity. The main objective of the experiment was to synthesize tert-butyl chloride with the utilization of an SN1 mechanism and purifying it with a simple distillation set-up, wherein a mixture of different substances separate by taking advantage of the different volatility and boiling points of the individual components. Tertiary alcohols are the most conducive alcohols whenever those must be synthesized into alkyl halides. In the experiment, hydrochloric acid was used in order to react with tert-butyl chloride to produce tert-butyl alcohol through an SN1 reaction. This reation includes three steps. The first part is the rapid, reversible (through hydrolysis) protonation of the alcohol followed by a slower rate-determining step which is the loss of water, eventually producing a more stable tertiary carbocation. To conclude the process, the carbocation is swiftly attack by the halogen ion (chloride in this experiment) in order to form the alkyl halide. Alkyl halide is insoluble in water, making it easy for it to separate from the aqueous layer. Hydrochloric acid was then mixed with tert-butyl alcohol producing water and tert-butyl chloride and was purified through distillation. Eventually, a clear and colorless solution of alkyl halide was synthesized, 0.8 milliliters in volume, with only a 7.38% percent yield. It can be concluded that the synthesis of alkyl halides with the reaction between an alcohol and a...