[Rayq]

i am required to obtain a very pure ester. so i carry out synthesis, isolation and the distillation. during distillation, i will be distillating alcohol and ester. in my case, i used 1-butanol and ethanoic acid to produce butyl acetate. butanol has a lower boiling point thus it will condense first. this will contaminate the condenser with butanol and thus the ester that i will obtain will not be pure. can i wash away the butanol using water just like in isolation or is there any other way to obtain a pure ester.

[Burner]

Boiling points data(From Chemspider):
Butyl acetate 124-126 °C
1-Butanol 117-118 °C
Ethanoic acid 118 °C

Butyl acetate has the highest boiling point among the three chemicals in your mixture. So you can just heat your mixture in the distillation set-up until all 1-butanol and ethanoic acid boils and be separated out from the mixture.

[Arkcon]

You can stop the distillation, and switch vessels.  There also exists a type of glassware known as a cow or pig -- basically a receiving flask with mini flasks that you rotate into position at a time point of your choosing.

[Babcock_Hall]

 Are you following a standard protocol?  Can you think of a protocol that would remove the ethanoic acid prior to distillation?  Why don't you look up the miscibility of butanol and water?