how will you bring about the following transformation. (1) ethyl magnesium bromide to ethane. (2) benzoic acid to benzoyl chloride. (3) benzyl bromide to benzyl alcohol.
Answers
Transforming one compound into another :
(1) Ethyl magnesium bromide to ethane
C₂H₅MgBr + H₂O → C₂H₆ + Mg(OH)Br
• The hydrolysis of ethyl magnesium bromide with water breaks the bond between carbon and magnesium.
• The hydrogen ion from water migrates towards the carbon, forming ethane.
(2) Benzoic acid to benzoyl chloride
C₆H₅COOH + SOCl₂ → C₆H₅COCl + SO₂ + HCl
• Benzoic acid is converted into benzoyl chloride by reacting it with sulphurous dichloride, commonly known as thionyl chloride.
• SOCl₂ is chosen over other chlorides because it gives two gases, SO₂ and HCl as by-products, which escape and leave behind benzoyl chloride only.
(3) Benzyl bromide to benzyl alcohol
C₆H₅CH₂Br + aq. KOH → C₆H₅CH₂OH + KBr
Benzyl bromide on being reacted with an aqueous solution of potassium hydroxide gives benzyl alcohol and potassium bromide.