A novel stable silylated ZSM-5 zeolite with tunableshape-selectivity for the methylation of toluene to produce p-xylene VIJAYKUMAR MARAKATTI PoornaPrajna Institute of scientific research Bangalore.
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. ZSM-5 zeolite- Acidity arises from framework Al.- high thermal stability.- Heterogeneous shape selective catalyst.
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, plasticetc in industry. CH 3 COOH COOCH3 oxida tion e s te rifica tion (O) (CH3 OH) CH 3 COOH COOCH3 PTA DMT
O O O O O O O O O O Si O Si O Si O Si - O SiO- Si O Si O Si O Si O O O O O O O O O OO- 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
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. Reflux for 6 h Filter & 1M NH4NO3 Dry Alumina/ silica binder Mixed wel Silylation with TEOS Activate 540 CReflux for 6 h Cool dry Activate Distillation REACTION 540 C
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.
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/gmAAS aanalyst 200,Perkin Elmer,PPISR.N2Sorption Omnisorb-100CX(Coulter analyzer)NCL,PUNE.
3.SEM IMAGES SAR -84 SAR -187Leica Stereoscan-440,(EDAX),NCL ,PUNE.
Continuous down flow tubular quartz reactor PreheaterSyringe Pump Quartz reactor(Tol+MeOH) Catalytic bed Automated Micro reactor TEMP CondenserH2 Gas Products
Effect of SAR SAR 272 showed better conversion and stability but lower PX selectivity Methanol utilization improved by 6% with increase in SARReaction Conditions: Catalyst wt: 10g, Temp = 480 °C, WHSV = 10 h-1Tol: MeOH = 4:1, H2: HC = 0, H2O/HC = 1, time = 3h, Pressure = 1 atm
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-1Tol: 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 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.
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.