. Complete the reaction when vapour of – 2-methyl-butan-2-ol is passed through red hot Cu-tube?

When the vapor of 2-methyl-butan-2-ol is passed through a red-hot copper tube, a significant reaction occurs, primarily involving dehydration and rearrangement. This process leads to the formation of alkenes through the elimination of water. Let's break down the reaction step by step.

The Structure of 2-Methyl-Butan-2-ol

2-Methyl-butan-2-ol is a tertiary alcohol, which means that the hydroxyl group (-OH) is attached to a carbon atom that is connected to three other carbon atoms. Its molecular formula is C₅H₁₂O, and its structure can be represented as follows:

• Central carbon (C) with the -OH group.
• Two methyl groups (–CH₃) attached to the central carbon.
• One butyl chain (–C₃H₇) connected to the central carbon.

Reaction Mechanism

When 2-methyl-butan-2-ol is heated in the presence of red-hot copper, the following reactions take place:

1. Dehydration: The heat causes the hydroxyl group (-OH) to be eliminated as water (H₂O). This process is known as dehydration.
2. Formation of Alkenes: The removal of water leads to the formation of a double bond between the adjacent carbon atoms, resulting in the formation of alkenes.

Products of the Reaction

The primary product from this reaction is 2-methylbut-2-ene, which is formed due to the stability of the double bond created during the dehydration process. The reaction can be summarized as follows:

C₅H₁₂O (2-methyl-butan-2-ol) → C₅H₁₀ (2-methylbut-2-ene) + H₂O

Factors Influencing the Reaction

Several factors can influence the outcome of this reaction:

• Temperature: Higher temperatures favor the elimination reaction, promoting the formation of alkenes.
• Copper Surface: The red-hot copper acts as a catalyst, facilitating the dehydration process.
• Concentration: The concentration of the alcohol can also affect the rate and extent of the reaction.

Summary of the Reaction

In summary, when 2-methyl-butan-2-ol is passed through a red-hot copper tube, it undergoes dehydration to form 2-methylbut-2-ene and water. This reaction highlights the importance of heat and catalysts in organic reactions, particularly in the formation of alkenes from alcohols.