[vanklik]

In the reaction of ethanoic acid with ethanol what possible impurities will include in addition to unreacted starting materials and water produced by the reaction?

Thank you!

[Arctic-Nation]

Very little, actually. Both reagents are stable under the conditions used (acid catalysis), with the possible exception of tar formation in the presence of excess acid, but that's something you actively have to mess up. A small amount of diethyl ether, perhaps, too, but that requires higher temperatures to be formed in any inconveniencing quantities.

[vanklik]

That's great! Thanks! 

[xiaojunzhang]

maybe ether will appear，I  think.