Question

Why is the preparation of alkynes by dehydrohalogenation often carried out in two steps?

a) Sodamide acts as a base deprotonating the dihalide
b) Sodamide acts as a nucleophile displacing halides
c) To control the reaction and prevent runaway polymerization
d) All of the above

Answer 1

The dehydrohalogenation of alkyl halides to form alkynes is typically performed in two steps to achieve control over the reaction and prevent over-dehydrohalogenation or polymerization, ensuring the desired alkyne is obtained.

Step-by-step explanation:

The preparation of alkynes by dehydrohalogenation is often carried out in two steps to control the reaction and prevent further reactions such as runaway polymerization. This two-step process is not solely because sodamide acts as a base or nucleophile, although it does indeed act as a base in the deprotonating step. The reasons behind a two-step method include controlling the reaction to obtain a specific product and avoiding over-dehydrohalogenation which can lead to side reactions or polymerization. The stepwise approach allows for precise removal of hydrogen halides to achieve the alkyne compound without further unsought transformations.