Functionalized Silica

SiliCycle is the leader in the development of functionalized silica gels, gathered under the name SiliaBond, for use in organic synthesis. The backbone of all SiliaBond products is SiliCycle SiliaFlash® F60 which provides superior performance for all types of applications due to the narrow particle size distribution and high purity. All the products in this section are made of standard flash silica gel, namely 40-63µm, 60A. SiliCycle is able to provide all functionalized products on any silica of this catalog (SiliaFlash, IMPAQ™, SiliaSphere™ and SiliaSphere™ PC) in any format (SiliaPrep™ SPE and SiliaSep™, SiliaSep, etc.) on a custom basis.

The use of solid supported reagents and scavengers is an excellent way to expedite organic synthesis by simplifying the purification process. Standard purification procedures including chromatography, liquid-liquid extraction, and crystallization can be time-consuming and difficult to scale up. In many cases, supported reagents have distinct advantages over their solution-phase counterparts, the biggest one being the ability to do multiple transformations in a single pot, the immobilization of toxic reagents, and increased selectivity. They are suitable for use in batch reactions and in flow through applications.

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For all the listed SiliaBond sorbents from SiliCycle, particle size is 40 – 63 μm and pore diameter is 60 Å. Please note that any irregular SiliaFlash or spherical SiliaSphere PC silica gel, with the function of your choice can be accommodated. Simply contact us for more information.

All functionalized SiliaBond sorbents are available in bulk but also pre-packed in SiliaPrep SPE cartridges and SiliaSep flash cartridges.

Reversed-Phases

In reversed-phase chromatography, the packing material is always hydrophobic (non polar) while the mobile phase is polar. The more hydrophobic the packing material, the more retention of non polar analytes. Usual reversed-phases are standard alkyl chains grafted on silica (C18, C8, C4, C1) and cyclic or aromatic functions (Phenyl, Pentafluorophenyl, Cyclohexyl).

Important parameters to keep in mind in reversed-phase chromatography:

• Carbon load (% C) will give the relative hydrophobicity of the packing media. Most of the time, it varies between 4 % and 19 %.
• Endcapping: it is impossible to react with all available silanol groups (free -OH groups on the silica surface) when functionalizing silica. But these free silanols are acidic and will react with basic compounds, so we endcap them with a capping agent to avoid non-specific bindings.

Normal Phases

In normal phase chromatography, the packing material is always polar while the mobile phase is non polar. The interactions between analytes and sorbent mainly take place on the highly polar silanols of the silica gel surface. Some hydrogen bonds can also happen on polar functionalized groups. Usual normal phases are ungrafted silica, polar functions (amino, cyano and diol) or alternative adsorbents (Alumina and Florisil for example).

Ion Exchange Phases

In ion exchange chromatography, both silica support and analytes must be ionized. If the stationary phase (packing material) is positively charged, anionic analytes only will retain (these phases are called WAX & SAX). And in the contrary if the stationary phase is negatively charged, cationic analytes only will retain (these phases are called WCX & SCX). Hence, pH of the mobile phase is of crucial importance and needs to be chosen carefully, so that both functions are charged.

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• Extremely easy product / API isolation and purification (simple & quick filtration of the heterogeneous support)
• Eliminates or strongly reduces the need for laborious purifications
• No leaching of silica or catalyst and no cross contamination
• Highly suitable for either batch or continuous flow applications
• Convenient for high throughput medicinal & discovery chemistry
• Improved reactivity & selectivity over homogeneous reagents / catalyst
• Compares very favourably to polymer-based reagents: no swelling, thermally stable, more easily scalabe, faster kinetics, compatible with all solvents and mechanically stable.

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SiliCycle’s SiliaMetS Metal Scavengers are functionalized silica gels designed to react and bind excess metal complexes.  In recent years, the time pressure associated with quickly bringing candidate drugs to market has increased the number of transition metal-catalyzed reactions being transferred from lead optimization to early scale-up. The removal of post-reactions metal residues has become a major issue in the pharmaceutical industry. Purification of APIs from residual metal catalyst by traditional methods (chromatography, activated carbon, distillation, etc.) often leads to problems such as high costs, time loss, low efficiency, and reduced API yields. To overcome these limitations, SiliCycle has developed SiliaMetS Metal Scavengers, a range of products that have significantly changed how chemists can purify APIs.

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