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Specific heat of Isoprene

Specific heat of Isoprene

Specific heat of Isoprene

(OP)
Can anyone help me out with the specific heat of Isoprene or Isobutylene?

RE: Specific heat of Isoprene

From NIST webbook, for liquids

isoprene at 25 Celsius, 152 J/(mol.K)            MW: 68.12
isobutylene at -20 Celsius, 121.4 J/(mol.K)     MW: 56.11

RE: Specific heat of Isoprene

Further to 25362's values, here are the constants for a temperature dependent equation:
Cp(liq) = A + B*T + C*T^2 + D*T^3, where
Cp(liq) is in [J/(mol K)]
and T is in [K]
REFERENCE: Carl L. Yaws "Chemical Properties Handbook" (McGraw-Hill, 1999).  A great general reference, probably the most comprehensive in the open literature.  For hydrocarbons, however, I would normally have used the API Technical Data Book except that liquid heat capacities are found using an indirect method.

Yaws' constants for isoprene liquid:
A= 80.542
B= 0.45089
C= -0.0016166
D= 2.7723E-6
Tmin = 128
Tmax = 436
CHECK: Cp(liq) at 25 C = 144.75 [J/(mol K)]


Yaws' constants for isobutylene (or isobutene) liquid:
A= 57.611
B= 0.56251
C= -0.0022985
D= 4.1773E-6
Tmin = 134
Tmax = 376
CHECK: Cp(liq) at 25 C = 131.72 [J/(mol K)]
                                
    T(C)    T(K)    Cp(liq)Isoprene    "25362"        % Error        Cp(liq)Isobutene      "25362"      % Error
    25    298.15    144.746              152              -4.77             131.715         
    -20    253.15    136.060                                                      120.480                 21.4       -0.758

For isoprene, the error between the value from 25362 and that from the above equation is < 5%, acceptable for this property which is not commonly measured and usually estimated from correlations, e.g., Poling, Prausnitz, and O'Connell, "The Properties of Gases and Liquids" (5th Ed., McGraw-Hill, 2001).

RE: Specific heat of Isoprene

Sorry, I had a typographical error on the Cp of liquid isobutene at -20 C; it should be 121.4, not 21.4.

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