Chemical Equilibrium of the Esterification Reaction Between Propanol and Ethanoic Acid

I am trying to investigate the relationship between temperature and equilibrium constant of the esterification reaction between propanol and ethanoic acid in reflux system, with conc. sulphuric acid as the catalyst. I plan to extract the ester (as I like the fruity smell) and measure the mass of the ester formed, by:



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> 1. Measuring $\pu{50 cm3}$ of propanol and conc. ethanoic acid using a pipette
> 2. Add the propanol, conc. ethanoic acid and $\pu{5 drops}$ of conc. sulphuric acid into a reflux system
> 3. Put the system into a water bath set to $\pu{20 ^\circ C}$, $\pu{40 ^\circ C}$, $\pu{60 ^\circ C}$, $\pu{80 ^\circ C}$, and $\pu{100 ^\circ C}$
> 4. Wait until the system reaches equilibrium (the part I am struggling with)
> 5. Remove the two acids (and thus stopping the reaction) using excess $\ce{Na2CO3 (aq)}$
> 6. Remove alcohol using excess $\ce{CaCl2 (aq)}$
> 7. Use a separatory funnel to get rid of most of the aqueous solution
> 8. Use anhydrous $\ce{Na2SO4 (s)}$ to get rid of the remaining aqueous solution
> 9. Use distillation to obtain pure propyl ethanoate
> 10. Measure the mass of the propyl ethanoate to obtain the amount of propyl ethanoate (in $\pu{mol}$)
> 11. Use the I-C-E method to obtain the $K\_\mathrm{c}$ at that temperature ($\pu{20 ^\circ C}$, $\pu{40 ^\circ C}$, $\pu{60 ^\circ C}$, $\pu{80 ^\circ C}$, and $\pu{100 ^\circ C}$)
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Here comes the problem. How can I determine whether the reaction has reached chemical equilibrium or not? I plan to use the I-C-E method to obtain the $K\_\mathrm{c}$ but if the system hasn't reached equilibrium yet before I quench the reaction, it will be pointless to obtain the mass of the ester. I have thought of measuring the $\mathrm{pH}$ value of the system using a data logging pH meter (since the concentration of ethanoic acid will decrease), but my teacher said it will not work as conc. sulphuric acid is present. Or maybe measure the conductivity of the mixture using a data logger (the pasco-capstone one)? Does that work?


Also, I am supposed to compare my experimental values with literature values. However, I cannot find the literature value of the $K\_\mathrm{c}$ of this reaction on the internet. Does anyone know where I can find the Kc value across different temperatures of this reaction?


In addition, the boiling points of propanol ($\pu{97 ^\circ C}$), ethanoic acid ($\pu{118 ^\circ C}$), water ($\pu{100 ^\circ C}$) and propyl ethanoate ($\pu{102 ^\circ C}$) are very similar. How can I ensure that there will only be pure ester in the distillate?


