1. Examples for heterogeneous reaction

2. Model Discrimination e
H2 + C2H4  C2H6
Is carried over molybdenum catalyst
run
Rxn rate PE
PEA PH 1 2
3.13 3
5.12 5 4
3.82
4.2 6
2.4
0.5 7
3.8 8
2.2 9
0.75

10. Tut 12

11. P10-4(a,c)
t-butyl alcohol (TBA) produced by liquid phase hydration (W) of isobutene (I) over Amberlyst-15 catalyst. The system is multiphase mixture of hydrocarbon, water and solid catalysts.

12. solution

13. (a) Surface reaction limited

14. (C) Eley Rideal Kinetics

15. P10-9
Methyl-ethyl ketone (MEK) produced from dehydrogenation of butan-2-ol (Bu) over zinc oxide catalyst
Bu  MEK +H2 (A  B+C)
The following data giving the reaction rate for MEK obtained from differential reactor at 490C
P(Bu) 2
0.1
0.5 1
P(MEK) 5
P(H2) 10
r’(MEK)
0.044
0.04
0.069
0.06
0.043
0.059

16. P10-9 Suggest a rate law consist with the exp. Data
P(Bu) 2
0.1
0.5 1
P(MEK) 5
P(H2) 10
r’(MEK)
0.044
0.04
0.069
0.06
0.043
0.059
Any increase in Bu parial pressure slightly increases the reaction rate

17. P10-9 Suggest a rate law consist with the exp. Data
P(Bu) 2
0.1
0.5 1
P(MEK) 5
P(H2) 10
r’(MEK)
0.044
0.04
0.069
0.06
0.043
0.059
MEK partial pressure has little effect on the reaction rate

18. P10-9 Suggest a rate law consist with the exp. Data
P(Bu) 2
0.1
0.5 1
P(MEK) 5
P(H2) 10
r’(MEK)
0.044
0.04
0.069
0.06
0.043
0.059
The partial pressure of H2 has no effect on the reaction rate

19. For H2 and MEK showing little effect we may propose a reaction rate
P(Bu) 2
0.1
0.5 1
r’(MEK)
0.044
0.04
0.069
0.06
0.043
0.059
r’(MEK)
P(Bu)

20. P10-9
(b) Suggest a reaction mechanism and a rate limiting step consistent with the rate law.
One possible mechanism
Assume step 2 is the limiting step and the others are steady state

23. (c) Plot conversion up to 90% and reaction rate as function of catalyst weight for an entering molar flow rate of pure Bu of 10 mol /min and an entering pressure P0=10atm, Wmax = 23kg

24. (PBu/r’MEK)0.5
PBu

28. Now consider the change in pressure

31. Cyclohexanol  Cyclohexene+water
P10-11
Cyclohexene is produced by passing cyclohexanol over catalyst
Cyclohexanol  Cyclohexene+water
It is suspected that the reaction may involve dual-site mechanism but not known for certain. It is believed that the adsorption equilibrium constant for cyclohexanol is around 1 and it is roughly around One or Two orders of magnitude greater than the adsorption equilibrium constants for other compounds.
Suggest a rate law and mechanism consistent with the data given
Determine the constants needed for the rate law
Why do you think estimates of the rate law parameters were given.

32. Run
Reaction rate *105 P
(cyclohexanol)
P (cyclohexene)
P (H2O) 1
3.3 2
1.05 5 3
0.565 10 4
1.826
1.49 6
1.36 7
1.08 8
0.862 9
1.37

35. (b)
To evaluate the rate constants use Polymath with non-linear equation regression
k =
KA= 4.76
KB= 0.259
KC=0.424

36. Tut 12

37. P10-14

38. P10-14

39. Low PTTIP: 2ND order Rxn
Since 1>>KP2TTIP/PPI
High PTTIP:
1<<KP2TTIP/PPI 0-order Rxn
High temperature
KI very small such that P2TTIPKPKI<<PPI

40. P10-20(a)

41. P10-20(b)