PoornaPrajna Institute of scientific researchBangalore.

A novel stable silylated ZSM-5 zeolite with tunable shape-selectivity for the methylation of toluene to

produce p-xylene

VIJAYKUMAR MARAKATTI

Outline Of Talk

# Introduction to zeolites.

# Synthesis of zeolites .

# Surface modification.

# Catalyst Characterization.

# Toluene methylation study.

# Conclusions.

What are ZEOLITES ?

- microporous crystalline aluminosilicates- Strong Brönsted acidity.- Acidity arises from framework Al.- high thermal stability.- Heterogeneous shape selective catalyst.

ZSM-5 zeolite

Eco-Friendly Catalyst for Alkylation of Toluene

p-xylene (27%) o-xylene(23%) m-xylene (50%)

ZSM-5

Toluene Methanol

CH3

CH3

CH3

CH3

CH3

CH3

COOCH3

COOCH3

CH3

CH3

COOH

COOH

oxidation

(O)

esterification

(CH3OH)

PTA DMT

* PTA & DMT are raw material for the synthesis of polyester, plastic etc in industry.

B.P 138 °C 139°C 144°C

Application

+ CH3OH

CH3

CH3

CH3OH

CH3

ZSM-5

O O OOOO O O O

Si

O

Si

O

OSi

O

O O- Si

O

O O Si

Si

O

Si

O

OSi

O

O O O Si - O Si

O O

Si

O

Si

O

OSi

O

O O- Si

O

O O

Si

O

Si

O

OSi

O

O O- Si

O

O O

O

CH3CH3

CH3

CH3

CH3

CH3CH3

CH3

PORE

Synthesis of ZeoliteZeolites 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

Lab Procedure for making Extrudates & silylation.

1M NH4NO3Reflux for 6 h Filter &

Dry

Alumina/ silica binder Mixed well

Activate

540 C

Silylation with TEOS

Reflux for 6 h

Distillation Cool dry

Activate

540 CREACTION

1.XRD

Characterization of ZEOLITES

BRUKER D2 Phaser, PPISR.

5 10 15 20 25 30 35 40

SAR 408

SAR 272

SAR 187

SAR 84

Inte

nsi

ty (

a.u

.)

2 (°)

2. N2 Sorption and AAS Study

HZSM5(1)

HZSM5(2) HZSM5(3)

HZSM5(4)

SiO2/Al2O3 Mole Ratio

84 187 272 408

Surface Area

m2/gm

380 352 356 380

AAS aanalyst 200,Perkin Elmer,PPISR.N2Sorption Omnisorb-100CX(Coulter analyzer)NCL,PUNE.

3.SEM IMAGES

SAR -84

SAR -187Leica Stereoscan-440,(EDAX),NCL ,PUNE.

H2 Gas

TEMP

Syringe Pump

Catalytic bed

(Tol+MeOH)

Condenser

Quartz reactor

Preheater

Products

Continuous down flow tubular quartz reactor

Automated Micro reactor

Results of reaction

1.Effect of silylation Zeolite + alumina extudates

Wt% TEOS

Toluene conversion (wt%) *

p-Xylene selectvity(wt%)

HZSM-5 SAR-187

0 9.4 40

HZSM-5 SAR-187

32 9.3 80.5

HZSM-5 SAR-187

64 8.7 90.4

HZSM-5 SAR-187

96 5.1 88.2

Reaction Conditions: Catalyst wt: 2g, Tol: MeOH mole ratio: 8:1, H2: HC = 2,WHSV = 4 h-1,

time = 3h, Pressure = 1 atm

2.Selection of Catalyst recipe

Catalyst with Different SiO2/Al 2O3 ratio

Toluene Conversion (Wt%)

p-xylene selectivity(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

Effect of 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

SAR 272 showed better conversion and stability but lower PX selectivity

Methanol utilization improved by 6% with increase in SAR

3.Efect of BinderBinder Zeolite Toluene

conversion P-xylene selectivity

Alumina

Silica

SAR-187

SAR-187

8.7

9.5

90.4

93

4.Effect of Tol: MeOH mole ratio

HZSM-187 With silica binder

Tol:MeOH Toluene conversion

P-xylene selectivity

Silica 864

9.513.416.6

939292.8

5.Effect of WHSVWHSV Toluene

conversion P-xylene selectivity

346

1816.616.1

91.292.894.1

Reaction Conditions: Catalyst wt: 2g, Tol: MeOH mole ratio: 4:1, H2:

HC = 2,WHSV = 4 h-1, time = 3h, Pressure = 1 atm

6.Effect of Temperature

7. Life and stabality of catalyst

Catalyst Temperature

Toluene Conversion

P-xylene selectivity

SAR-187 Silica binder With 32 Wt % TEOS

410 15 92

435 16.6 92.8

460 18.7 91.1

0 5 10 15 2010

20

30

40

50

60

70

80

90

100

toluene conversion

p-xylene selectivity

time in hours

8. Effect of hydrogen pressure

CatalystSilylated ZSM-5 extrudates SAR 187

Test Conditions 435C, 50psig

H2O &H2

435C, 2psig

H2O &H2

Liquid HC 6 hr 6hrBenzene 0.16 0.02Toluene 79.63 79.44Ethyl Benzene 0.09 0.03p-xylene 9.21 10.45m-xylene 1.69 0.76o-xylene 0.56 0.16Ethyl toluenes 2.71 0.65Trimethyl benzenes 0.27 0.03C10 armatics and others 0.31 0.06Conversion & Selectivity (mol%)Toluene conversion 13.7 11.7Mixed xylene selectivity 78.5 94.0p-xylene selectivity 80.4 92.0MeOH Utilization 46% 44%

Pressure effect!Conversions improved by 2%

Selectivities dropped by 12%

Higher Ethyl toluene!

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

Conclusion

Silica to alumina ratio of zeolite was optimized to obtain good conversion and high PX selectivity. SAR 187 found to be better with H2 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 H2 pressure.

Presently the reactions with water and no H2 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.

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.