# Reactions of alcohol with sulfuric acid

I knew two chemical reactions of alcohol with sulfuric acid

1. $\ce{CH3CH2OH + H2SO4 -> CH2CH2}$
Here product is having a double bond (ethene) and this reaction happens at 443 K temperature.

2. $\ce{CH3CH2OH + H2SO4 -> C2H5OC2H5}$
Here product is ether an happens at 413 K temperature.

But today I came across another reaction.

1. $\ce{C2H5OH + H2SO4 -> C2H5OSO2OH + H2O}$

Now my question is when will this third reaction happen? Any specific temperature?

The book from which I found this reaction doesn't describe anything. Just says: Alcohols react with inorganic acids (except halogen acids) to form inorganic esters.

• Have you tried searching? en.wikipedia.org/wiki/Organosulfate – Mithoron Dec 7 '15 at 20:47
• @Mithoron It doesn't say anything about this reaction. – manshu Dec 7 '15 at 20:52
• You understand that these are equilibrium reactions, which happen concurrently and lots of things affect those equilibria? – Mithoron Dec 7 '15 at 21:04
• @Mithoron You mean to say these are three different Major products at different temperatures? – manshu Dec 7 '15 at 21:06
• Yes, but you can also influence concentrations directly on start and during reaction. Also pressure, additional compounds like solvent and other factor may be important. – Mithoron Dec 7 '15 at 21:14

## 2 Answers

This article on Wikipedia says your compound, ethyl sulphate, can be synthesized, by adding sulfuric acid drop-wise to boiling ethanol and temperature should be kept below 413K which agrees with your data. I found also an article according to which authors conducted esterification at about 300K, but with starting presence of anhydrous sodium sulfate.

Also proportion of reagents should be right, if you add more than equimolar amount of acid, removal of leftover is problematic, as sulfuric acid has high boiling point and there's no suitable selective extractant.

• See: "The Ethyl Sulfuric Acid Reaction", Evans, P. N. and Albertson, J. M., J. Am. Chem. Soc., 1917, 39, 456. – user55119 Jan 1 '18 at 23:08

Actually this is the product produces when ethene reacts with sulphuric acid. You can say like that firstly ethyl alcohol coverts to ethene and futher it reacts with sulphuric acid to give $\ce{CH3-CH2-OSO3H}$. It futher reacts with water to give ethyl achohol again at $\pu{100 ^\circ C}$