Q 11-11-78 E - Organic Chemistry (Mcmurry)

Question

When primary alcohol is treated with p-toluenesulfonyl chloride at room temperature in the presence of an organic base such as pyridine, a tosylate is formed. When the same reaction is carried out at a higher temperature, an alkyl chloride is often formed. Explain.

 

Step-by-Step Solution

Answer

Due to further reaction of chlorine ion with –Otos group. . 

At room temperature

At room temperature toluenesulfonyl group of p-toluenesulfonyl chloride forms a new bond with oxygen of primary alcohol giving tosylate.

At a high temperature

The Toluenesulfonyl group of p-toluenesulfonyl chloride forms a bond with the oxygen of alcohol to give tosylate but at higher temperatures chloride ion displaces –Otos group to give organochloride.