Metal Catalyst for Dimethylnaphthalene Dehydrogenation

The patent employs a composite catalyst system combining multiple metal components (Pt, Sn, In, K, Mg, Cs, Zn, Ga) with sulfur addition on a carrier material. This composite structure allows synergistic effects where each component contributes specific functions: Pt provides dehydrogenation activity, Sn/In enhance selectivity, K/Mg/Cs promote stability, and sulfur prevents coke formation. The composite material approach resolves the contradiction by maintaining high activity through metal synergy while ensuring long-term stability through distributed functional components.

The patent optimizes specific parameter ranges for each catalyst component to achieve the desired balance between activity and stability. The metal content ratios (Pt: 0.05-2.5 wt%, Sn/In: 0.1-3.0 wt%, K/Mg/Cs: 0.5-15.0 wt%, Zn/Ga: 0.01-3.0 wt%, Sulfur: 0.01-4.0 wt%) are carefully controlled to maximize dehydrogenation activity while preventing catalyst deterioration. This parameter optimization ensures that the catalyst maintains both high productivity and reliability under reaction conditions.

The composite catalyst structure with multiple metal components distributed on a robust carrier material provides both high reaction activity and mechanical strength. The carrier material serves as a stable support that maintains structural integrity under high temperature and pressure, while the dispersed metal components facilitate the dehydrogenation reaction. This composite architecture resolves the contradiction by separating the functions of structural support and catalytic activity.

Different regions of the catalyst possess different properties: the carrier material provides mechanical strength and thermal stability, while the metal components concentrated at active sites provide catalytic activity. The sulfur addition specifically targets coke prevention at the metal-active sites. This local quality differentiation allows the catalyst to simultaneously withstand harsh conditions and maintain high reaction rates.

The patent converts the harmful effect of coke formation into a beneficial outcome by adding sulfur (0.01-4.0 wt%) to the catalyst system. Sulfur acts as a coke inhibitor, preventing carbon deposition that would otherwise deactivate the catalyst. This transforms the potential harm of extended operation (coke accumulation) into a benefit (maintained activity over time), enabling longer catalyst lifespan while sustaining high production volumes.

The multi-component composite catalyst system enhances long-term durability through synergistic effects. K, Mg, and Cs components specifically contribute to thermal stability and resistance against sintering during extended operation. The combination of these stabilizing elements with the active metal components creates a robust catalyst that maintains both high productivity and extended lifespan under continuous reaction conditions.

The composite catalyst system assigns specific functions to different components: Pt (0.05-2.5 wt%) and Sn/In (0.1-3.0 wt%) primarily drive dehydrogenation activity and reaction rate, while K (0.5-15.0 wt%), Mg (0.5-15.0 wt%), and Cs (0.5-15.0 wt%) components enhance selectivity by modifying the electronic and geometric properties of the active sites. This functional differentiation within the composite material allows simultaneous optimization of both rate and selectivity.

The patent optimizes the ratio and concentration parameters of each metal component to achieve the desired balance between rate and selectivity. By carefully controlling the content of each element within specified ranges and optimizing their interactions, the catalyst achieves high dehydrogenation rates while maintaining excellent selectivity for the desired dimethylnaphthalene products.