In an E1 mechanism, a monomolecular elimination of water will result in an alkyl cation. In an E2 mechanism, a bimolecular reaction occurs in which water acts as a base, abstracting a -hydrogen. The direction of the elimination reaction forming alkenes is typically governed by Zaitsev's rule. Zaitsev's rule states that the most highly substituted alkene will be formed preferentially, which basically states that the double bond folds towards the more substituted carbon. .
Objective and Materials:.
The materials for this experiment is listed on page 87-92(Organic Chemistry laboratory Manual, Haden/McNeil, 2003-04).
Procedure:.
The procedure for this experiment is listed on page 87-92.
(Organic Chemistry laboratory Manual, Haden/McNeil, 2003-04).
Data:.
All data is in laboratory notebook.
Calculations:.
The following is a calculation for approximation of area of triangular peak:.
Area = Height * ½ base .
The following is a sample calculation of the area produced by 1-butene from 2-butanol.
55cm^2 = 1.1cm * ½ (1cm).
The following is a calculation of percent chemical component(Given known order):.
% component = Area of component Total area of all components * 100.
The following is a sample calculation of % 1-butene from 2-butanol.
4.6% = 0.55cm^2 11.76cm^2 * 100.
Results:.
The following is a chart of retention time and percent product from 2-butanol:.
Components % product Retention Time (s).
1-butene 4.6 16.
trans-2-butene 67.3 16.
cis-2-butene 28.1 16.
The following is a chart of retention time and percent product from 2bromobutane:.
Components % product Retention Time (s).
1-butene 19.1 18.
trans-2-butene 69.9 18.
cis-2-butene 11 18.
- It was found that trans-2-butene formed the most product in both cases.
Discussion:.
The objective of this experiment is to successfully perform a dehydration of a 2-butanol and a dehydrohalogenation of 2-bromobutane to form the products 1-butene, trans-2-butene, and cis-2-butene.
