Question

Ethyl hydrogen sulphate when heated with excess of ethyl alcohol at 413k,it gives

Answer 1

The above stated reaction occurs as

C2H5OHC2H5OH −→−−−H2SO4→H2SO4 C2H5−O−C2H5C2H5−O−C2H5 + H2OH2O

This reaction has a two step mechanism. It is as follows

Step I: Formation of ethyl hydrogen sulphate- Ethyl alcohol molecule reacts with Sulphuric acid molecule to form Ethyl hydrogen sulphate & water

C2H5OHC2H5OH + H−OSO3HH−OSO3H −→−−−−−−413K/140°C→413K/140°C C2H5−OSO3HC2H5−OSO3H + H2OH2O

Step II: Formation of Diethyl ether- Ethyl hydrogen sulphate molecule reacts with another Ethyl alcohol molecule to form Diethyl ether & Sulphuric acid

C2H5OSO3HC2H5OSO3H + H−O−C2H5H−O−C2H5 −→−−−−−−413K/140°C→413K/140°C C2H5−O−C2H5C2H5−O−C2H5 + H2SO4H2SO4

The Sulphuric acid consumed during the first step is regenerated in the second step, which can be reused in first step. Thus large amount of ethyl alcohol can be converted into diethyl ether by usung smaoo amount of sulphuric acid. Hence this reaction is also known as continuous etherification process.