Silylation is one of the method by w

1. A novel stable silylated ZSM-5 zeolite with tunable
shape-selectivity for the methylation of toluene to
produce p-xylene
VIJAYKUMAR MARAKATTI
PoornaPrajna Institute of scientific research
Bangalore.

2. Outline Of Talk
# Introduction to zeolites.
# Synthesis of zeolites .
# Surface modification.
# Catalyst Characterization.
# Toluene methylation study.
# Conclusions.

3. What are ZEOLITES ?
- microporous crystalline
aluminosilicates
- Strong Brönsted acidity.
ZSM-5 zeolite
- Acidity arises from framework Al.
- high thermal stability.
- Heterogeneous shape selective
catalyst.

4. Eco-Friendly Catalyst for Alkylation of Toluene
CH3 CH3
CH3
ZSM-5 CH3
+ CH3OH
CH3 CH3
Toluene Methanol p-xylene (27%) o-xylene(23%) m-xylene
(50%)
B.P 138 °C 139°C 144°C
Application
* PTA & DMT are raw material for the synthesis of polyester, plastic
etc in industry.
CH 3 COOH COOCH3
oxida tion e s te rifica tion
(O) (CH3 OH)
CH 3 COOH COOCH3
PTA DMT

5. CH3
CH3
ZSM-5
CH 3 O
H

6. O O O O O
O O O O
O Si O Si O Si O Si - O Si
O- Si O Si O Si O Si O
O O O O O O O O O
O- Si O Si O Si O Si O O- Si O Si O Si O Si O Si
O O O O O O O O O
CH3
CH3
CH3
PORE CH3
CH3
CH3
CH3
CH3

7. Synthesis of Zeolite
Zeolites are synthesized by hydrothermal method.
Silica source: Tetra ethyl orthosilicate(TEOS).
Template : Tetrapropyl ammonium bromide.
(TPABr)
Aluminum source : Aluminum sulfate.
Solvent : Water
Gel autoclave 170 °C for 3 days.
Calcined at 550 °C to remove template .
By above method zeolites with different SiO2/Al2O3
ratio 84, 187, 272, and 408 are synthesized

8. Lab Procedure for making Extrudates & silylation.
Reflux for 6 h Filter &
1M NH4NO3
Dry
Alumina/
silica binder Mixed wel
Silylation with TEOS Activate
540 C
Reflux for 6 h
Cool dry Activate
Distillation
REACTION
540 C

9. Characterization of ZEOLITES
1.XRD
SAR 84
Intensity (a.u.)
SAR 187
SAR 272
SAR 408
5 10 15 20 25 30 35 40
2θ (°)
BRUKER D2 Phaser, PPISR.

10. 2. N2 Sorption and AAS Study
HZSM5(1) HZSM5(2) HZSM5(3) HZSM5(4)
SiO2/Al2O 84 187 272 408
3 Mole
Ratio
Surface 380 352 356 380
Area
m2/gm
AAS aanalyst 200,Perkin Elmer,PPISR.
N2Sorption Omnisorb-100CX(Coulter analyzer)NCL,PUNE.

11. 3.SEM IMAGES
SAR -84
SAR -187
Leica Stereoscan-440,(EDAX),NCL ,PUNE.

12. Continuous down flow tubular quartz reactor
Preheater
Syringe Pump Quartz reactor
(Tol+MeOH)
Catalytic bed
Automated Micro reactor
TEMP
Condenser
H2 Gas Products

13. Results of reaction
1.Effect of silylation
Zeolite + alumina Wt% TEOS Toluene p-Xylene
extudates conversion (wt%) * selectvity
(wt%)
HZSM-5 SAR- 0 9.4 40
187
HZSM-5 SAR- 32 9.3 80.5
187
HZSM-5 SAR- 64 8.7 90.4
187
HZSM-5 SAR- 96 5.1 88.2
187
Reaction Conditions: Catalyst wt: 2g, Tol: MeOH mole ratio: 8:1, H2: HC = 2,WHSV = 4 h-1,
time = 3h, Pressure = 1 atm

14. 2.Selection of Catalyst recipe
Catalyst with Toluene p-xylene selectivity
Different Conversion (Wt%)
SiO2/Al 2O3 ratio (Wt%)
84 9.5 85
187 8.7 90.4
272 8.5 85.0
408 7.5 87.0
Reaction Conditions: Catalyst wt: 2g, Tol: MeOH mole ratio: 8:1, H2: HC = 2, WHSV = 4 h-1,
time = 3h, Pressure = 1 atm

15. Effect of SAR
SAR 272 showed
better conversion
and stability but
lower PX selectivity
Methanol utilization
improved by 6%
with increase in SAR
Reaction Conditions: Catalyst wt: 10g, Temp = 480 °C, WHSV = 10 h-1
Tol: MeOH = 4:1, H2: HC = 0, H2O/HC = 1, time = 3h, Pressure = 1 atm

16. 3.Efect of Binder
Binder Zeolite Toluene P-xylene
conversion selectivity
Alumina SAR-187 8.7 90.4
Silica SAR-187 9.5 93
4.Effect of Tol: MeOH mole ratio
HZSM-187 With Tol:MeOH Toluene P-xylene
silica binder conversion selectivity
Silica 8 9.5 93
6 13.4 92
4 16.6 92.8
5.Effect of WHSV
WHSV Toluene P-xylene Reaction Conditions: Catalyst wt:
conversion selectivity 2g, Tol: MeOH mole ratio: 4:1, H2:
3 18 91.2 HC = 2,WHSV = 4 h-1, time = 3h,
4 16.6 92.8 Pressure = 1 atm
6 16.1 94.1

17. 6.Effect of Temperature
Catalyst Temperature Toluene P-xylene
Conversion selectivity
SAR-187 410 15 92
Silica
binder With 435 16.6 92.8
32 Wt % 460 18.7 91.1
TEOS
7. Life and stabality of catalyst
100
90
p-xylene selectivity
80
70
60
50
40
30
toluene conversion
20
10
0 5 10 15 20
time in hours

18. 8. Effect of hydrogen pressure
Catalyst
Silylated ZSM-5 extrudates SAR 187
Test Conditions 435C, 50psig 435C,
H2O &H2 2psig
H2O &H2
Pressure effect!
Liquid HC 6 hr 6hr
Conversions
Benzene 0.16 0.02 improved by 2%
Toluene 79.63 79.44
Ethyl Benzene
p-xylene
0.09 0.03 Selectivities
9.21 10.45
m-xylene 1.69 0.76
dropped by 12%
o-xylene 0.56 0.16
Ethyl toluenes 2.71 0.65 Higher Ethyl
Trimethyl benzenes 0.27 0.03
C10 armatics and others 0.31 0.06
toluene!
Conversion & Selectivity (mol%)
Toluene conversion 13.7 11.7
Mixed xylene selectivity 78.5 94.0
p-xylene selectivity 80.4 92.0
MeOH Utilization 46% 44%

19. 9. Effect of water
Water effect!
Higher catalyst
stability
Mix Xylenes
improved
Increase in PX
selectivity
Ethyl toluenes
decreased
Improved MeOH
utilization
by 10%
Reaction Conditions: SAR 187, Catalyst wt: 10g, Temp = 480 °C, WHSV = 10 h-1
Tol: MeOH = 4:1, H2: HC = 0, H2O/HC = 1, time = 3h, Pressure = 1 atm

20. Conclusion
 Silica to alumina ratio of zeolite was optimized to obtain good conversion and
high PX selectivity. SAR 187 found to be better with H 2 and water. But without H2 ,
SAR 187 showed slow deactivation where as SAR 272 showed better stability.
 Silica binder was found to be better than alumina.
 Under H2 pressure, conversion improved but PX and MX selectivities decreased
by 12%. It is better to operate at low or no H 2 pressure.
 Presently the reactions with water and no H 2 are underway. SAR 272 showed good
stability in the absence of H2 .
Advantages of water in the stream
The toluene conversion and mix Xylenes improved. Better catalyst
stability and higher methanol utilization.
 Study of catalyst life with time indicated good catalyst stability upto
22h with once increase in temperature by 5°C.

21. Acknowledgement
 Poornaprajna Institute Of Scientific Research for giving an
healthy environment and all facilities to carry out the
research activity.
Admar mutt education foundation for providing fellowship.
 Dr. A.B Halgeri Director for his encouragement and support.
 all the scientists , lab mates and administrative staff of PPISR.