Carboxylic Acid Chloride and Alcohol Reaction | Preparing Ester

Esters can be prepared from reaction of carboxylic acid chlorides and alcohols to give ester as the product.

We discuss about this reaction and preparing esters with a organic conversion problem. After the problem, some example reactions and properties of this reaction are explained in detail.



Question

Synthesis following ester from 2-bromopropane. You can use only use following compounds.


The ester, wants to prepare

ester

alcoholic KOH, HBr, organic peroxide, PCl3, H+ / KMnO4, dilute NaOH


2-bromopropane

2-bromopropane is an alkyl halide compound with three carbon atoms. Bromine atom is positioned at 2nd carbon atom in the molecule.

2-bromopropane

Ester preparation methods

  1. from reaction of carboxylic acid chlorides and alcohols
  2. from reaction of carboxylic acid, concentrated sulfuric acid and alcohols

Reaction of carboxylic acid chlorides and alcohols is the best way to prepare esters.


Reaction of carboxylic acid chlorides and alcohols

Ester and hydrogen halide are given as the products and this reaction is not a reversible reaction like carboxylic acid and alcohol reaction. So if we want to get a good yield of ester, we want to mix a carboxylic acid chloride and an alcohol as reactants.


carboxylic acid chloride and alcohol reaction

But we are not given a carboxylic acid chloride and an alcohol. Only we have an alkyl halide compound. Therefore we have to convert that alkyl halide to alcohol compound and carboxylic acid chloride.


Now, we are going to discuss about each reactions which are used to convert 2-bromopropane to given ester.


Propanoyl chloride and 2-propanol reaction

Propanoyl chloride and 2-propanol react to give ester as the product.



Preparing carboxylic acid chloride | Propanoyl chloride


2-bromopropane and alcoholic KOH reaction

When an alkyl halide is heated with alcoholic KOH, alkene is given as the product. Also hydrogen halide is formed as a by product with alkene. So 2-bromopropane will give propene as the product when heated with NaOH.


Propene and HBr reaction in the presence of organic peroxide

In the presence of organic peroxide, addition of HBr molecule happens according to the Anti-Markovnikov rule. That means, halogen atom is added to the carbon atom which has more hydrogen atoms.

In this case, 1-bromopropane is given as the product from the reaction of propene and HBr in the presence of organic peroxide.


1-bromopropane and aqueous NaOH reaction

Bromine atom is replaced by hydroxyl ion in the NaOH. Propanol is given as the organic product.


Propanol oxidation by strong oxidation agents

Carboxylic acids are given when primary alcohols are oxidized by strong oxidizing agents. So propanoic acid is the product after the oxidation of propanol.


Propanoic acid and PCl3 reaction

Propanoyl chloride is given as the product.



2-bromopropane and aqueous NaOH reaction

Propane-2-ol is prodyced as the product when aqueous NaOH is added to the 2-bromopropane.



Complete conversion of ester preparing

2-bromopropane to ester

How do you identify, the reaction is being happened?

When esters are formed, a scent is spread. Usually carboxylic acids and alcohols have unpleasant odor.



Example reactions of carboxylic acid chloride and alcohol

Now we see some examples which will help you to learn more about this reaction.


Ethanoyl chloride and ethanol reaction

Ethyl ethanoate and HCl is given as the products when ethanoyl chloride reacts with ethanol.

ethanoyl chloride and ethanol reaction

Benzoyl chloride and methanol reaction

When -COCl group is combined with a benzene group, we call it benzoyl chloride. When methanol is added to the benzoyl chloride, methyl benzoate is produced as the ester. Also HCl is given as a by product.

benzoyl chloride and methanol reaction


Properties of carboxylic acid reaction and alcohol reaction

  • Do not want a catalyst to occur the reaction.
  • Not a reversible reaction. So best way of producing ester.
  • Hydrogen chloride (HCl) is given as a by product.

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