Polysciences, Inc. now offers the latest in silica based “precious metal” recovery systems for heavy metal scavenging of heterogeneous or homogeneous catalysts in API synthesis.
Thiol-SAMMS®* stands for “Self Assembled Monolayers on Mesoporous Support”. Molecularly engineered mesoporous functionalized silica has the unique ability to bind palladium and other precious metals. The high surface area and functional thiol binding sites give the Thiol-SAMMS® tremendous capacity and kinetics to absorb such metals very quickly in catalyzed reactions.
Advantages of Thiol-SAMMS® technology:
- Adsorption of 99% of targeted metals in minutes
- Capacity up to 60% of SAMMS weight
- Operational over a wide pH range (pH 2-12)
- Meets the requirements of TCLP (EPA Toxicity Characteristic Leaching Procedure)
- Allows for the reclamation of metals and adsorbents
Features of Thiol-SAMMS® technology vs. competitive systems including:
- Superior scavenging for a range of metals such as Pd, Pt, Rh, Ru, Au, Ag, Cu, Cd, Hg and Pb
- Metals may be in colloidal form, oxidized or zero - valent
- Solvent compatible for homogeneous catalysts
- Controlled pore size structures with high specific surface area
- Excellent filtration behavior
- High thermal stability with excellent thermal and structural stability
- Thiol-SAMMS® may be used in batch mode or fixed bed mode
- Available as a test kit for quick sample evaluations and bulk quantities
- Cost effective compared to alternative commercial technologies
Precious metals (e.g. Palladium, Platinum, Rhodium, Ruthenium, Silver and Copper) are versatile catalysts in many organic reactions:
- Cross-coupling reactions: Buchwalk-Hartwig, Heck, Suzuki, Talladacycles and Sonogashiras
- Hydrogenation (aromatic rings, carbonyl compounds, carboxylic acids, heterocyclics, nitriles, nitro compounds, oximes, etc.)
Catalysis is a very versatile tool for chemical synthesis. Heterogeneous or homogeneous catalyst may be used, and in most cases contain precious or transition metals. However, chemical reactions utilizing such catalyst can be detrimental to product quality and product yield. In the case of active pharmaceutical ingredients (APIs), the metal catalyst must be removed to a regulated level.
| Physical Properties of Thiol-SAMMS®
|Average particle size (micron, d50)
|Tap Density (g/cc)
** THMS-M1 is a ferrite based magnetic support that allows for magnetic removal of the support containing the captured metal.
Thiol-SAMMS® metal removal adsorption rates are very rapid (minutes). For comparison, Palladium adsorption of a 1mM Pd(2+) buffered solution at pH 4 is complete (99%) within 200 minutes. Platinum removal occurs slightly slower but is 99.7% complete in 500 minutes. Capacities of 0.1 mmole/gram of Thiol-SAMMS® with palladium and 0.1 mmole/grams for platinum have been demonstrated. The fast kinetics are observed even in the presence of many cations and anions. Silver, Cadmium, Palladium, Mercury and Nickel show insensitivity to phosphate, sulfate, cyanide, calcium, potassium, sodium, silica and zinc ions. Conditions will vary by process and each process should be evaluated independently.
Polysciences, Inc. offers a test kit for quick sample evaluations that includes THMS-03 (50 grams), THMS-04 (50 grams) and THMS-M1 (100 gram sample) for testing of laboratory scale waste stream removal. Technical Data Sheet #782 is supplied with the kit as a starting point to assist in preliminary process development. Please Note: THMS-03 and THMS-04 are interchangeable in terms of capacity and performance.
Related Press Reference:
- New standards proposed by U.S. Pharmacopeia will change how drugmakers analyze and report metal impurities by early 2010.
- Chemical & Engineering News (December 8, 2008) pp. 32-34, "Improving Metal Detection in Drugs"
All materials are commercially available in bulk quantities, please call for quotation.
For convenience in laboratory scale testing, Polysciences, Inc. also offers rare earth block magnets (Neodymium-Iron-Boron) or Multi-SEP Magnetic separator magnets that will accommodate test tubes for metal separation.
* Thiol-SAMMS® technology is supplied by Polysciences, Inc. under agreement with Steward Environmental Solutions, Chattanooga, TN