Preparation of 2-Chloro-2-Methylbutane in Sn1 Reaction

De’Neisha Bailey

Organic 2 lab

Lab report 1

Preparation of 2-chloro-2-methylbutane in Sn1 reaction

Introduction

Alkyl halides are also known as haloalkane. These are a chemical group of chemical compounds derived from alkanes containing one or more halogens. The common halogens includes: fluorine, chlorine, bromine, and iodine. There electronegativities is significantly higher that carbon. The functional group is polarized so that the carbon is electrophilc and the halogen is nucleophilic. A Sn1 reaction is a nucleophilic substitution reaction that is used to create a variety of compounds. In this reaction Sn1 is used to convert an alcohol into 2-chloro-2-methylbutane. The alcohol that is used in this reaction is t-amyl alcohol.

Theory

Tertiary alcohols are converted when combined with halides. This reaction is usually a fast reaction effected by temperature and the reaction with hydrohalogen acids. Secondary alcohols and the preparation of the halides usually have slower reactions. The preparation of the halides of primary alcohols is even slower and required prolonged heating in order to react. Tertiary alcohols under certain conditions perform a Sn1 reaction and an intermediate carbocation is formed.

[pic 1]

Procedure

Obtain a separatory funnel and place 10 mL of 2-methyl-2-butanol and 25-mL of concentrated hydrochloric acid. Swirl the content to mix the reactants. Stopper the funnel and invert carefully for 1 minute. Open the stopcock to release some of the excess pressure. Continue to do this several times. Place the funnel on a ringstand and allow the mixture to separate into two distinct layers. Determine which the organic layer is. Drain the aqueous layer in a waste beaker. Obtain 10-mL portions of saturated aqueous sodium chloride and 10-mL of cold saturated aqueous sodium bicarbonate. Wash with organic layer with the sodium chloride first. Invert the content and release the pressure as done before. Allow the two layers to separate, and then drain the aqueous layer. Now wash the organic layer with the cold sodium bicarbonate. Invert the content and release the pressure as done before. Allow the two layers to separate, and then drain the aqueous layer. Another wash will be performed first with 10-mL of water and then again with 10-mL of saturated aqueous sodium chloride. Remove the aqueous layer. Transfer the organic layer into a 25-mL Erlenmeyer flask. Dry the product with several spatulas full of anhydrous sodium sulfate. Swirl the flask for 10-15 minutes until the product is dry. Liquid should appear clear, if it looks cloudy, add more anhydrous sodium sulfate.

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