Question

propanoic acid treated with Cl2/red p, H2O(catalyst)?​

Answer 1

Answer:

Hell-Volhard-Zelinskii Reaction

The treatment of carboxylic acids with bromine and phosphorus tribromide (PBr3) or a mixture of bromine and phosphorus, yields the α-bromocarboxylic acid. Phosphorus tribromide is often applied only as a catalyst. Thus, if chlorine and PBr3 are applied, chlorination occurs instead of bromination.

The reaction is known as the Hell-Volhard-Zelinskii reaction (after J. Volhard, C.M. Hell, and N.D. Zelinskii). In the frist reaction step, PBr3 converts the carboxylic acid into the corresponding acyl bromide. The acyl bromide is in equlibrium with the corresponding enol. A nucleophilic attack of the enol π bond on a bromine molecule yields HBr and an α-bromoacyl bromide, which may be isolated.

For­ma­tion of the in­ter­me­di­ate α-bro­moa­cyl bro­mide in the Hell-Vol­hard-Zelin­skii re­ac­tion

Analogous to acyl halides, α-bromoacyl halides may be converted into α-bromoesters, α-bromocarboxamides, and "back" to the α-bromocarboxylic acid. However, their α bromine atom may also be exchanged for another nucleophile in an SN2 reaction. The α-cyanocarboxylic acids and α-aminocarboxylic acids are, for example, available in this way.

Fig.6 Ap­pli­ca­tions of α-bro­moa­cyl halides

If catalytic amounts of PBr3 are applied, the intermediate α-bromoacyl bromide is attacked by another carboxylic acid molecule, yielding the corresponding anhydride. The bromide that is released during anhydride formation, then cleaves the anhydride into an α-bromocarboxylic acid - the product - and an acyl bromide. The acyl bromide reenters the reaction cycle.......

Answer 2

The propanoic acid treated with Cl2/red p, H2O(catalyst)

Explanation:

Propanoic acid is a member of Carboxylic acid .

1. The molecular formula is CH₃CH₂COOH
2. This reaction comes under some of the special reaction of carboxylic acids  in which the carboxylic  acid reacts with halogen that is X₂ in presence of red phosphorous to form alpha halo acid .
3. In case of propanoic acid when reacted with Chlorine in presence of red phosphorous , it forms 2-Chloro ethanoic acid .
4. The reaction for the same is attached below .