CHEM 233 Lecture Notes - Lecture 8: Hjo, Alkene
7 Dec 2015
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Document Summary
Preparation of alkenes by e1 and e2 elimination reactions. Figure 1: (top) e2 elimination reaction and (bottom) e1 elimination. The purpose of this lab is to from two alkene isomers through two separate elimination reactions. In one reaction, 2-methyl-1-butene and 2-methyl-2-butene are prepared by dehydration of 2-methyl-2-propanol with h2so4 through an e1 elimination reaction. In a separate reaction, the same two alkenes were derived from dehydrohalogenation of 2-chloro-2-methylbutane which was obtained from lab 7 with koh through an e2 elimination reaction. Elimination reactions are used to make carbon-carbon -bonds. These two reactions, their mechanism, important characteristics, and also their regioselectivity are explained thoroughly in the equations that are shown below. In dehydrohalogenation of alkyl halides, the electronegative halogen of the alkyl halide has a polar characteristic causing a partial positive charge ( +) on the carbon and a partial negative charge ( -) on the halogen.
