# How does sulfuric acid catalyze the preparation of esters?

Nov 17, 2015

Because it is very hygroscopic.

#### Explanation:

It litterally tears out ${H}_{2} O$ combinations out of substances that do not even contain water, as long as it contains $H$'s and $O$'s. That's why sulfuric acid is so dangerous, as it rips away these $H$'s and $O$'s from all organic material, like skin...
As you might know, esterization is the combination of a alkanoic acid (${R}_{1} - C O O H$) with an alcohol (${R}_{2} - O H$), where the $R$'s are the stuff that's attached to it.

It goes like this:

${R}_{1} - C O O H + {R}_{2} - O H r i g h t \le f t h a r p \infty n s {R}_{1} - C O O - {R}_{2} + {H}_{2} O$

This is an equilibrium reaction. If you remove one of the reaction products (in this case water) the reaction will shift to the right.

Note: in this view, sulfuric acid is not really a catalyst, because it changes (becomes more diluted) in the process.