How Can You Calculate the Temperature-Dependent Heat Capacity of Ethyl Acetate?

[sicjeff]

I need the heat capacity Ethyl Acetate as a function of temperature. I've seen books that give heat capacity as a function of functional group, but the problem is they are only at one temperature. What I basically need is some coefficients that would fit into the equation Cp= A +BT+CT^2+DT^-2. For this capacity, I can approximate Ethyl Acetate as a liquid operating from 298.15K to approximately 373.15K (I know this isn't realistic because the boiling point of ethyl acetate is around 350.25K).

I have already checked Perry's Handbook and other various thermochemical fluid properties texts, but I still can't find anything.

Thanks for any assistance you can give me.

 

[Q_Goest]

Hi sicjeff,
Can you be more specific? What pressure and what temperature range to you need?

 

[sicjeff]

Thanks for responding. I am running my reaction at temperature ranges of 298.15-373.15 K and my pressure will be in the area of 1 bar.

 

[Q_Goest]

Hi sicjeff,
I have a computerized database that has these values in it, but it doesn't give equations. You can print out values and then do a curve fit though. Also, the database is in English units, so you'll need to convert to metric.

I'm assuming you mean a pressure of 1 bara, not 1 barg. If you need it for 1 barg, I can simply change the value and give you the same spreadsheet if you'd like.

At 1 bara, it shows a saturation temperature of roughly 170.85 F which is where the disjoint is in the spreadsheet.

Hope that helps.

 

[Q_Goest]

sicjeff,
I'm not sure what you're using this for, but I suspect you're working out the equation so you can integrate it and determine the change of state between two temperatures, such as by adding X amount of heat.

You might consider simply using enthalpy and internal energy directly instead. They're generally much easier to work with IMO. Coming up with an equation for U or H as a function of temperature is just as easy as Cp.

 

[sicjeff]

Actually I'm doing reaction equillibria with the extended van't Hoff equation. Thank you so very much for your assistance.

Can I get the name of the database you are using if you don't mind?

 

[whitshadw8]

If we say Cp=α+βT+γT^2 and Cp=a +bT+cT^-2, combined, we get your equation Cp=A+BT+CT^2+DT^-2. (Intro. to Chemical Engineering, Pavia, pp 127)

Since I couldn’t find coefficients for your derived formula, I looked up the coefficients of Cp=α+βT+γT^2. Basically Coefficient α = 7.235; Coefficient β= 0.4072; Coefficient γ =2.092E-04. Units of Cp are in kJ/kg-mol , Temperature in Kelvins.
http://www.cheric.org/kdb/kdb/hcprop/showcoef.php?cmpid=1059&prop=CPG

You see that there is another coefficient (Coefficient D), if Cp=α+βT+γT^2 was extended to another higher power.