2. Parameters Effect On Scavenging Efficiency
A metal scavenging study using SiliaBond® Metal Scavengers products was conducted on various metal catalysts commonly used in organic synthesis. Various parameters were studied for their influence on the scavengers' robustness as well as to establish the best conditions to bring the level of metal down to an acceptable level for the pharmaceutical industry (i.e.: solvent, number of equivalents, temperature, reaction time, and nature of the catalyst).
Solvent effect on Scavenging Efficiency
SiliaBond Metal Scavengers can safely be used in any organic and aqueous solvents. However, the nature of the solvent does sometimes influence the scavenging efficiency.
Reaction Time and Number of Equivalents effect on Scavenging Efficiency
The fast scavenging kinetic of SiliaBond Metal Scavengers allows the reduction of the residual metal concentration to very low ppm in a few minutes. However, various parameters affect the kinetic. The influence of reaction time, temperature, and number of equivalents used are parameters to consider.
12 Item(s)
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SiliaMetS® Thiol
SiliaMetS® Thiol (Si-Thiol) is a robust metal scavenger for a variety of metals including Pd, Pt, Cu, Ag and Pb under a wide range of conditions. It has been used in pharmaceutical processes up to the pilot plant scale. It is our most versatile metal scavenger and is the preferred metal scavenger for Pd(II), Cu, Ag, and Hg.
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SiliaMetS® Thiourea
SiliaMetS® Thiourea (Si-THU) is a versatile metal scavenger for all forms of palladium and is widely used in the pharmaceutical industry. It works particularly well in organic solvents. It can also be used to scavenge Ag, Pt, Ru, Rh and Hg. Once complexed with a transition metal, it has been reported as being an effective catalyst.
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SiliaMetS® Cysteine
SiliaMetS® Cysteine (Si-Cys) is the silica bound equivalent of the amino acid Cysteine. By attaching the molecule to the backbone via the amino group, the thiol group remains free and accessible for higher metal scavenging efficiency. It is a versatile metal scavenger for a variety of metals including Pd, Sn, Ru, Pt, Cu, Rh, Cd and Sc under a wide range of conditions and the preferred metal scavenger for tin residues.
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SiliaMetS® Dimercaptotriazine (DMT)
SiliaMetS® DMT (Si-DMT) is the silica bound equivalent of 2,4,6-trimercaptotriazine (trithiocyanuric acid). It is a versatile metal scavenger for a variety of metals including Cd, Co, Ni, Pd, Pt, Rh, and Ru under a wide range of conditions and the preferred metal scavenger for ruthenium catalysts.
TMT has been reported to efficiently remove palladium and heavy metals by precipitation. Unfortunately, its solubility in organic solvents causes problem. SiliaMetS DMT solves this issue and almost all solvents can now be used.
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SiliaBond® Amine
SiliaBond® Amine (Si-NH2) is an effective scavenger of acid chlorides, sulfonyl chlorides, isocyanates and other electrophiles. Si-NH2 has been shown to be effective metal scavenger and catalyst for Knoevenagel reactions. SiliaBond Amine is also used in chromatography as normal phase sorbent.
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SiliaBond® Amine nec
SiliaBond® Amine (Si-NH2) is an effective scavenger of acid chlorides, sulfonyl chlorides, isocyanates and other electrophiles. Si-NH2 has been shown to be effective metal scavenger and catalyst for Knoevenagel reactions. SiliaBond Amine is also used in chromatography as normal phase sorbent.
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SiliaMetS® Diamine
SiliaMetS® Diamine (Si-DIA) is a proven scavenger for metals and electrophiles. It scavenges acids, acid chlorides, anhydrides, aldehydes, isocyanates, and chloroformates as well as Pb, Ni, and Cd.
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SiliaMetS® Triamine
SiliaMetS® Triamine (SiliaMetS WAX-3, Si-TRI) is effective for scavenging metals such as Pb, Co, Ru and Pd. Our screening studies have shown it to be the preferred scavenger for Pb. It can also be used as a scavenger for acid chlorides, isocyanates and other electrophiles.
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SiliaMetS® Imidazole
SiliaMetS® Imidazole (Si-IMI) is a versatile metal scavenger for a variety of metals including Cd, Co, Cu, Fe, Ni, Pd, and Rh under a wide range of conditions and the preferred metal scavenger for iron catalysts.
SiliaMetS Imidazole can also be used as an amine base in systems that are generally sensitive to basic conditions compared to other SiliaMetS supported bases.
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SiliaMetS® TAAcOH
SiliaMetS® TAAcOH (SiliaMetS Triaminetetraacetic Acid) is a silica bound metal scavenger for Pd(0), Ni(0) and Cu. It is the supported version of EDTA in its free form. It is an effective scavenger for metals in low or zero oxidation states, which includes many of the most synthetically useful catalysts such as tetrakis-(triphenylphosphine)palladium(0).
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SiliaMetS® TAAcONa
SiliaMetS® TAAcONa or (or SiliaMetS Triaminetetraacetate, sodium salt) is a silica bound metal scavenger for Pd(II), Ni(II) and Cu. It is the supported version of EDTA in its sodium salt form. It is an effective scavenger for metals in higher oxidation state, 2+ or higher.
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SiliaMetS® Metal Scavenger Kit
Cysteine - DMT - Imidazole - Triamine - TAAcOH - TAAcONa - Thiol - Thiourea
12 Item(s)
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- Metal to Remove
- Family / Formats
- Phases
- Pore Size
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- 60 Å (11)
- Endcapping
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- Endcapped (12)
- Non-endcapped (2)
- Particle Size
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