Benzene Reaction

1
Benzene Reaction

• Catalytic Reaction

2
Reaction

• C6H5CH3 H2 ? C6H6 CH4
• Toluene Hydrogen?BenzeneMethane
• On a clinoptiloite (SiO2-Al2O3) catalyst

3
Mechanism

• Overall Reaction
• T(g)H2(g)?B(g)M(g)
• Adsorption
• T(g) S ??TS
• Surface Reaction
• TS H2(g) ??BSM(g)
• Desorption
• BS ?? B(g) S
• Hydrogen and Methane not adsorbed

• rADkACvPT-kACTS/KT
• rSks CTS PH2 - ks CBS PM/KS
• rDkD CBS kDPBCv/KB

4
Surface Rxn is Rate Determining

• -rT(ksKT)PTPH2/(1KBPBKTPT)
• _at_600ºC catalyst bulk density, ?B2.3 g/cc
• (ksKT) 10,010 kmole/kgcat/s/atm2 e(-EA/RT)
• EA36.4 kcal/mole
• KB1.26/atm
• KT1.01/atm
• ln (Keq(T)) -?Grxn(T)/RT -(?Hrxn(T)-T ?Srxn)/RT
• ln (Keq(T)) -(?Hºrxn(TR) ?Cp(T-TR)-T ?Srxn)/RT

Fogler, H. S., Elements of Reaction
Engineering, 2nd Ed., Prentice Hall, 1992 p. 281
5
How Do we put this in Aspen?

• Rate kgmole/s/(holdup unit)
• Heterogeneous Catalysis
• Holdup unit kg catalyst
• Homogeneous Rxn
• Holdup unit m3
• ks1.386x10-8gmole/gmcat/s
• 2.3 gmcat/cm3kgmole/1000gmole