SiliaMetS®- Metal Scavengers Typical Experimental Procedures
Screening in Batch Reactor Mode (Bulk)
To select the best scavenger for initial screening experiments, do the following steps for each SiliaMetS Metal Scavengers included in the kit. Use 4-8 molar equivalents of each SiliaMetS in respect to the residual metal concentration.
- 1. Dissolve the crude product to be treated in a suitable solvent (or use directly the crude reaction mixture) and prepare vials containing the same solution volume.
- 2. Directly, add to these vials the amount needed for each SiliaMetS included in the kit. Note: no pre-wetting of the SiliaMetS is required. See "Calculation of the amount of SiliaMetS to use" page xx.
- 3. For initial tests, stir the solution for at least one hour at room temperature.
- 4. Scavenging progress can be followed by normal analytical techniques. The scavenging progress can be estimated by looking at the color of the solution as demonstrated in the figure. When the scavenging is almost completed, the solution is less colored and SiliaMetS becomes colored. In some occasional cases, if all the samples are still coloured, let them react for a longer time and/or add more equivalents of the SiliaMetS and/or increase the temperature of the reaction.
- 5. At the end of the scavenging, filter off the SiliaMetS using a fritted funnel or filtration device.
- 6. Wash the SiliaMetS with additional solvent for total recovery of the API (or compound of interest) and concentrate the solution under vacuum.
- 7. Analyze the residual metal concentration of each vial to identify the most efficient SiliaMetS Metal Scavenger. Note: you can choose more than one scavenger.
- 8. If you are satisfied with the scavenging efficiency of the best SiliaMetS, direct scale-up is possible. Otherwise, scavenging optimization can be done with SiliaMetS identified in #7 (see next section).
Screening with SiliaMetS Fixed Bed Mode (SPE or Flash Cartridges)
SiliaMetS fixed bed formats are a great alternative for metal removal and are directly scalable. Initial screening investigations can be done using SiliaPrep 2g/6mL SPE cartridges.
- 1. Condition the cartridge with 3-4 cartridge volume using the same solvent as the solution to be treated.
- 2. Add to the top of the cartridge the solution containing the API and the metal and let it pass through the cartridge under gravity
Note: if needed, a slight positive pressure on the top of the cartridge or a light vacuum can be applied to speed up the flow rate. - 3. As shown by the picture on the right, a dark coloured band will be observed on the top of the silica bed most of the time.
- 4. If the residual solution is still coloured, multiple passes through the same cartridge can be done.
- 5. Once the scavenging is completed, wash the cartridge using at least 3 column volumes of solvent to insure total API (or compound of interest) recovery. Note: in some particular cases, additional washing may be required.
Experiment Optimization with SiliaMetS
If, upon completion of the screening procedure, the scavenging is not completed or you wish to reduce the number of equivalents, or the reaction time, optimization can be undertaken.
Various parameters can be changed one at a time or simultaneously to improve the metal removal efficiency.
Note: you can mix multiple Silia MetS to get superior efficiency.
Number of SiliaMetS Equivalents
| For initial screening experiments we suggest to use 4-8 molar equivalents in respect to the residual metal concentration of each SiliaMetS. Once the preferred scavenger is identified, further optimization can be done to reduce the number of equivalents used (typically down to 2-4 equivalents). Graph represents residual concentration (%) of Pd(AcO)2 with SiliaMetS Thiol in DMR. |
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Subsequent Treatments with SiliaMetS
In some particular cases (equilibrium process or the presence of multiple species), multiple treatments with SiliaMetS could be suitable instead of one single treatment with a larger amount. For optimal results, filtration between each treatment can allow for a higher scavenging efficiency.
Reaction time
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In some particular cases, where increasing the temperature is impossible, longer contact time with the scavenger can allow higher scavenging efficiency. Conditions: Pd(AcO)2, THF, SiliaMetS Thiol, RT. |
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Temperature In initial screening, we suggest to run the scavenging experiments at room temperature. Usually, metal scavenging is completed after one hour or so. However, if the timescale is too long for your need, higher scavenging rates can be achieved by increasing the temperature. SiliaMetS can be safely used at elevated temperature without degradation and can be added either at room temperature or directly to warm solution. Mixing Rate SiliaMetS are mechanically stable and offer excellent scavenging efficiency in batch processes agitated with overhead and magnetic stirrers, as well as orbital shaking under low to moderate agitation rate. pH of Aqueous Solution When the scavenging is done in aqueous solution, it is possible to use SiliaMetS in a pH range of 2 to 12. Furthermore, depending on the nature of the SiliaMetS, pH can modify the nature of functional groups present on the scavengers by charging them. Scavenging can be affected (i.e.: amine groups in acidic conditions). Solvent SiliaMetS can safely be used in a wide range of organic and aqueous solvents commonly used in laboratory and in process, such as DMF, DMSO, THF, 2-butanone, alcohols, ethers, chlorinated solvent, etc. As demonstrated in the graphs below, the nature of the solvent does sometimes influence the scavenging efficiency. If scavenging or kinetic are too slow, changing solvent or co-solvent addition should be considered. SiliaMetS Format (Mode Used) One advantage of SiliaMetS is their great compatibility with various technologies. They can be used in batch, in fixed bed (SPE or Flash cartridges), in flow chemistry, or in microwave. Scavenging efficiency can be improved by changing the mode used. |
37 Item(s)
List Grid
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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 -
SiliaSep™ Flash Cartridges Amine
Good alternative for normal phase purification of compounds with basic properties, which would normally have to be purified by reversed-phase.
SiliaSep flash amine cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Triamine
SiliaSep flash triamine cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Diamine
SiliaSep flash diamine cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Thiol
SiliaSep flash thiol cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges TAAcOH
SiliaSep flash TAAcOH cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges TAAcONa
SiliaSep flash TAAcONa cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Thiourea
SiliaSep flash thiourea cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Dimercaptotriazine (DMT)
SiliaSep flash DMT cartridges offer a superior alternative to the other cartridges available on the market.
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SiliaSep™ Flash Cartridges Cysteine
SiliaSep flash cysteine cartridges offer a superior alternative to the other cartridges available on the market .
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SiliaSep™ Flash Cartridges - Open Top (OT) Amine
SiliaSep™ OT flash cartridges are compatible with FlashMaster instrument.
Good alternative for normal phase purification of compounds with basic properties, which would normally have to be purified by reversed-phase.
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SiliaSep™ Flash Cartridges - Open Top (OT) Thiol
SiliaSep™ OT flash cartridges are compatible with FlashMaster instrument.
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SiliaSep™ Flash Cartridges - Biotage™ Compatible (BT) Amine
SiliaSep™ BT flash cartridges are compatible with Biotage i-style compression modules.
Good alternative for normal phase purification of compounds with basic properties, which would normally have to be purified by reversed-phase.
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SiliaSep™ Flash Cartridges - Büchi™ Compatible (BU) Amine
SiliaSep™ BU flash cartridges are compatible with Büchi Sepacor flash chromatography instrument.
Good alternative for normal phase purification of compounds with basic properties, which would normally have to be purified by reversed-phase.
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SiliaPrep™ SPE Cartridges Amine (WAX)
SiliaPrep Amine is a weak anion exchanger sorbent used in replacement of SAX for strong anions to avoid irreversible retention. Can also be employed as a metal scavenger and norman phase conditions.
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SiliaPrep™ SPE Cartridges Amine nec (WAX)
SiliaPrep Amine nec is a weak anion exchanger sorbent used in replacement of SAX for strong anions to avoid irreversible retention. Can also be employed as a metal scavenger and norman phase conditions.
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SiliaPrep™ SPE Cartridges Diamine
SiliaPrep diamine can be used in replacement of SAX for strong anions to be irreversible retention. Can also be employed as metal scavenger and in normal-phase conditions.
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SiliaPrep™ SPE Cartridges Diamine nec
SiliaPrep diamine can be used in replacement of SAX for strong anions to be irreversible retention. Can also be employed as metal scavenger and in normal-phase conditions.
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SiliaPrep™ SPE Cartridges Triamine
SiliaPrep Metal Scavengers will lower the residual metal concentration of various metal complexes to single digit ppm.
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SiliaPrep™ SPE Cartridges Thiol
SiliaPrep Metal Scavengers will lower the residual metal concentration of various metal complexes to single digit ppm.
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SiliaPrep™ SPE Cartridges Thiourea
SiliaPrep Metal Scavengers will lower the residual metal concentration of various metal complexes to single digit ppm.
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SiliaPrep™ SPE Cartridges TAAcOH
SiliaPrep Metal Scavengers will lower the residual metal concentration of various metal complexes to single digit ppm.
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SiliaPrep™ SPE Cartridges TAAcONa
SiliaPrep Metal Scavengers will lower the residual metal concentration of variois metal complexes to single digit ppm.
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SiliaPrep™ SPE Cartridges Dimercaptotriazine (DMT)
SiliaPrep Metal Scavengers will lower the residual metal concentration of various metal complexes to single digit ppm.
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SiliaPrep™ 96 Well Plates Amine
Standard SiliaPrep 96 Well Plates are available in 2 mL with different bed weight up to 200 mg. Various sorbents are available and are divided into several sections based on sorbent characteristics.
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SiliaPrep™ 96 Well Plates Amine nec
Standard SiliaPrep 96 Well Plates are available in 2 mL with different bed weight up to 200 mg. Various sorbents are available and are divided into several sections based on sorbent characteristics.
37 Item(s)
List Grid
- Metal to Remove
- Family / Formats
- Phases
- Pore Size
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- 60 Å (36)
- Endcapping
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- Endcapped (35)
- Non-endcapped (3)
- Cartridges Volume
- Bed Weight
- Particle Size
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