Question

Draw the major product of the following alcohol dehydration in the presence of H2SO4. Use the Zaitsev rule (no rearrangements) to predict the major product when necessary. Include all hydrogen atoms.

Answer 1

Zaitsev rule. It may be possible in some instances to create a double bond through an alcohol dehydration reaction in which hydrogen atoms are lost from two different carbons on the carbocation. The major product is always the more highly substituted alkene, that is, the alkene with the greater number of substituents on the carbon atoms of the double bond, an observation called the Zaitsev rule. Thus, in the dehydration reaction of 2-butanol, the following products are formed.

он CH-CH-CH-CH,e 2-butene 1-butene

The Zaitsev rule predicts that the major product is 2-butene. Notice that each carbon atom involved in the double bond of 2-butene has one methyl group attached to it. In the case of 1-butene, one carbon atom of the double bond has one substituent (the ethyl group), while the other carbon atom has no substituents.

Answer 2

what is the alcohols (ethanol, methanol ?)