Conversion of C₈ aromatics over a dual-bed catalyst.

Area of Science:

• Catalysis
• Chemical Engineering
• Materials Science

Background:

• Efficient conversion of C8 aromatics is crucial for petrochemical processes.
• Traditional single-bed catalysts often face limitations in activity and selectivity for complex aromatic mixtures.
• Developing advanced catalytic materials is essential for optimizing aromatic hydrocarbon transformations.

Purpose of the Study:

• To design and synthesize a dual-bed catalyst for improved C8 aromatics conversion.
• To optimize the preparation of ZSM-5 and ZSM-39 components for specific reactions.
• To evaluate the performance of the dual-bed catalyst against conventional single-bed systems.

Main Methods:

• Preparation of a dual-bed catalyst comprising SiO2-coated ZSM-5 (upper layer) and ZSM-39 (lower layer).
• Modification of ZSM-5 using tetraethyl orthosilicate (TEOS) via chemical liquid deposition (CLD).
• Synthesis of ZSM-39 using pyrrolidine with controlled OH-/SiO2 molar ratio (0.05).

Main Results:

• Optimal catalytic performance for ZSM-5 achieved with 0.6 g TEOS per gram of catalyst.
• Optimal catalytic performance for ZSM-39 achieved at an OH-/SiO2 molar ratio of 0.05.
• The dual-bed catalyst, with a 1:1 mass ratio of upper to lower layers, showed superior activity and selectivity compared to single-bed ZSM-5.

Conclusions:

• The developed dual-bed catalyst effectively converts C8 aromatics.
• The synergistic combination of modified ZSM-5 for ethylbenzene dealkylation and ZSM-39 for xylene isomerization leads to enhanced performance.
• This dual-bed approach offers a promising strategy for improving catalytic processes involving aromatic hydrocarbons.