What reaction conditions most effectively convert a carboxylic acid to a methyl ester

Fischer Esterification

Explanation:

Fischer esterification or Fischer-Speier esterification is a carboxylic esterification reaction that uses an inorganic acid as a catalyst, mainly sulfuric acid (H2SO4).

The carboxylic acids are usually too weak acids, so they have little tendency to yield the proton (H + ) that they lose in the esterification.

A stronger acid, such as sulfuric acid, behaves like a proton donor and facilitates the esterification reaction.

First, sulfuric acid injects a proton into the carboxyl group

The alcohol molecule, R'-OH, has an electron-rich oxygen atom, is attracted to the protonated carboxylic structure

This complex is not very stable and stabilizes towards the most favorable energy molecule, which is the ester, releasing a water molecule and a proton (H + ). The proton is then used to regenerate sulfuric acid

Answer: The convenient and efficient sonochemical method for methyl esterification of carboxylic acids reaction conditions are;

• catalyzation by polymer-supported triphenylphosphine (0.1 eq. PS-PPh3)

• in the presence of 2,4,6-trichloro-1,3,5-triazine (1.0 eq. TCT) and Na2CO3 (2.0 eq.)

• Temperature 50°C for 10 - 30 mins

Explanation:

Methyl esters of various carboxylic acids bearing reactive hydroxyl groups as well as acid - or base-labile functionalities could be rapidly prepared within short times in good to excellent yields in high purities without column chromatography.