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

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The discussion focuses on calculating the temperature-dependent heat capacity of ethyl acetate, specifically seeking coefficients for the equation Cp = A + BT + CT^2 + DT^-2 over a temperature range of 298.15K to 373.15K at 1 bar pressure. Various resources, including Perry's Handbook, have been checked without success in finding the necessary coefficients. A participant suggests using a computerized database that provides values suitable for curve fitting, although it requires conversion from English to metric units. Another contributor mentions the possibility of using enthalpy and internal energy for calculations, which may simplify the process. Coefficients for a simplified heat capacity equation are also provided, indicating potential values for further analysis.
sicjeff
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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.
 
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Hi sicjeff,
Can you be more specific? What pressure and what temperature range to you need?
 
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.
 
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.
 

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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.
 
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?
 
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.
 
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