SiliaCat®- Heterogeneous Catalysts
SiliaCat is the new heterogeneous catalysts family from Silicycle. It is made by using an innovative technology that confers these materials advantageous properties for catalysis. SiliaCat is an organically modified silica made by a proprietary encapsulation process resulting in a new chemical matrix structure.1
SiliaCat is a leach-proof organoceramic matrix with high catalyst loading and surface area that provides high turn over number (TON).
1Org. Process Res. Dev. 11 (2007) 766
Advantages of using SiliaCat heterogeneous catalysts over competitive products include:
- High stability
- Rigid & Porous Structure (no swelling)
- Compatibility with a wide range of solvents
- Ease of use: no swelling or static charge
- High turnover number (TON)
- Fast kinetics
- Accurate loading
The SiliaCat Matrix
Inspired by the ORganically MOdified SILica (ORMOSIL) technology, the SiliaCat family is composed by new and innovative catalysts. Resulting from the co-condensation of two organosilane monomers by the sol-gel process (confer condensation mechanism below), the hybrid organic-inorganic materials present the highest stability and reactivity available with heterogeneous catalysts. Furthermore, the high cross linked framework presents an unmatched resistance, significantly better than the usual post-synthesis functionalized ligand.
Like any other silica-based material, SiliaCat presents the following:
- Easy to handle (free flowing, no static charge)
Easy to weigh and handle since silica does not carry a static charge and is always free flowing. Its high density makes it suitable for small volume work. It does not require extensive -washing for high recoveries and will not stick to glassware. It is amenable to automation.
- Robust (mechanically & thermally stable)
Works well with overhead stirring and can stand very high temperature; suitable for microwave synthesizers.
- Rigid & porous structure
- No swelling
- Solvent independent
Silica neither shrinks nor swells in any solvent.
- Fast kinetics
The rate of the reaction is not controlled by the diffusion in and out of the polymer (or other support). SiliaCat does not dictate the solvent of the reaction.
- Accurate loading
- Lot-to-lot reproducibility
Usually, heterogeneous catalysts supported on a silica matrix are immobilized by post-modification of the inorganic support. These supports, however, present a high degree of leaching due to the poor stability of the immobilized phase. With SiliaCat Heterogeneous Catalysts, the ligand is directly cross linked in an organic-inorganic framework. This results a high degree of stability of the catalysts. Compared to homogeneous catalysts, SiliaCat exhibits a good reactivity and selectivity with one of the major advantages being that the catalyst is eliminated from the reaction mixture by a simple filtration. Forget your purification problems with our SiliaCat catalysts family.
The process for using SiliaCat Heterogeneous Catalysts is outlined in the scheme below.
The significant costs associated with precious metal catalysts and their undesired tendency to remain in organic products has generated interest for an increase in reactivity and ways to recover and reuse these metals. SiliaCat® DPP-Pd is a unique diphenylphosphine palladium (II) heterogeneous catalysts made from a leach-resistant organoceramic matrix.
The significant costs associated with precious metal catalysts and their undesired tendency to remain in organic products has generated interest for an increase in reactivity and ways to recover and reuse these metals. SiliaCat® S-Pd is a unique thiol based palladium (II) heterogeneous catalysts made from a leach-resistant organoceramic matrix.
SiliaCat® TEMPO is a heterogeneous catalyst/reagent made from a proprietary class of organosilica-entrapped radicals suitable for the selective oxidation of delicate substrates into valued carbonyl derivatives.