課程名稱︰化學反應工程
課程性質︰必修
課程教師︰吳紀聖
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰102/05/15
考試時限（分鐘）：120
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1. (a) A reaction Tl+ + 2 Ce4+ ==> Tl3+ + 2 Ce3+ is catalyzed by Ag. Under
certain conditions, the rate is proportional to [Ce4+][Tl+]/[Ce3+].
Suggest a mechanism to explain this behavior. (2002 PhD.)
(b) If the irreversible reaction a A + b B ==> c C + d D, is elementary
as written The rate expression was -rA = k*Ca^(a)*Cb^(b), if we take
A as our basis and divide through equation by stoichiometric coefficient
of A so that the equation is expressed as A + b/a B ==> c/a C + d/a D.
Will the rate expression then become -rA = k Ca*Cb^(b/a)? Explain.
2. The gas phase decomposition A ==> B +2 C, is carried outin a constant volume
batch reactor. Run 1-5 are at 100 decree C and Run 6 is at 110.
(a) Determine the reaction order and specify rate constant.
(b) What is the activation energy?
Run Initial concentration, Ca0 (M) Half-life (min)
1 0.025 4.1
2 0.0133 7.7
3 0.010 9.8
4 0.05 1.96
5 0.075 1.3
6 0.025 2.0
3. To retard the motor oil degradation (by odidation), most oils (RH) contains
an antioxidant. Without an inhibator (antioxidant), the odidation occurs.
The suggested mechanism is following (left hand side). When an antioxidant
(AH) is added to retard degradation, the followubg addutuibal termination
steps occur (right hand side).
No antioxidant With antioxidant
I2 ==> 2I。 RO2。 + AH ==> ROOH + A 。
I。 +RH ==> R。+ HI A。 + RO2。 ==> inactive
R。+ O2 ==>RO2。
RO2。 + RH ==>ROOH + R 。
2RO2。 ==> inactive
(a) Derive a rate law for the degradation of oil without antioxidant.
(b) Derive a rate law for the degradation of oil with antioxidant.
4. A gas phase reaction is the hydrogenation of o-cresol to
2-methylcyclohexanone, o-cresol + 2H2 ==> 2-methylcyclohexanone.
The reaction on a nickle-silica catalyst was found to be zero-order in
o-cresol abd first order in hydrogen with a specific rate of
1.74 mol o-cresol / kg cat-min-atm at 170 degree C. The reaction mixture
enters the packed-bed tubular at a total pressure of 10atm. The molar feed
consists 67% hydrogen and 33% i-cresol at a total molar flow rate of
40 mol/min.
(a) Neglecting pressure drop in the packed bed reactor, what is the
ratio of catalyst weight needed to achieve the last 5% conversion
(94% ~ 99%) to the weight needed to achieve tje forst 5% conversion
(0% ~ 5%)?
(b) Accounting for pressure drop in the packed bed reactir, and using
a value of alpha = 0.34 (1/kg), derive differential equations of
conversion (dx/dw) and pressure drop (dy/dw).
5. (a) The rate law for hydrogenation (H) of ethylene (E) to form ethane (A)
over Co-Mo catalyst is following. Suggest a mechanism and rate-limiting
step consistent with the rate law.
-rA = k(Pe)*(Ph)/(1+(Ke)*(Pe))
(b) The formation of propanol on a catalytic surface is believed to be
proceed by the following mechanism.
Suggest a rate-limiting step and derive a rate law.
O2 + 2S <==> O。S
C3H6 + O。S ==> C3H5OH。S
C3H5OH。S <==> C3H5OH + S
============
gas constant R = 8314 Pa*L/(mol*K) = 82.06E-3 L-bar/(mol-K) = 1.987 cal/mol-K
Batch : Na (dX/dt) = -rA*V CSTR: V = Fa (Xout - Xin)/(-rA)out
PFR: Fao (dX/dV) = -rA
total points: 100
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