The synthesis of alkyl fluorides is best accomplished by :
(B) R–Cl + AgF R–F + AgCl
The synthesis of alkyl fluorides is best accomplished by the Swarts reaction. This reaction involves the conversion of alkyl chlorides or bromides into alkyl fluorides by heating them with metallic fluorides such as silver fluoride (AgF), mercurous fluoride (Hg2F2), or cobalt fluoride (CoF3). The reaction proceeds via a nucleophilic substitution mechanism where fluoride ion replaces the chloride or bromide ion.
The general reaction can be represented as:
where R is an alkyl group, X is Cl or Br, and M is a metal like Ag, Hg, or Co.
This method is preferred because direct fluorination using F2 is highly exothermic and difficult to control, often leading to side reactions such as carbon chain fragmentation. The Swarts reaction provides a controlled and efficient way to produce alkyl fluorides.
Now, let's evaluate the other options:
Thus, the correct choice is the Swarts reaction.
Nucleophilic Substitution Reactions: These involve the replacement of a leaving group by a nucleophile. The Swarts reaction is an example of this, where fluoride acts as the nucleophile.
Preparation of Haloalkanes: Various methods exist for synthesizing different haloalkanes, such as Finkelstein for iodides/bromides, and Swarts for fluorides.
Swarts Reaction Equation:
Match the reactions in column I with appropriate types of steps / reactive intermediate involved in these reactions as given in column II
| Column-I | Column-II |
 |
(p) Nucleophilic substitution |
 |
(q) Electrophilic substitution |
 |
(r) Dehydration |
 |
(s) Nucleophilic addition |
| (t) Carbanion |