Silica micropowder - ≥99.8% metals basis, sphere powder,200-300nm

Cat. No.: S131647

GRADE & PURITY ≥99.8% metals basis, sphere powder,200-300nm

Synonyms

Silicon dioxide

Shipped In

Normal

Specifications

Sinónimos

Silicon dioxide

Especificações e pureza

≥99.8% metals basis, sphere powder,200-300nm

Enviado em

Normal

Pureza

≥99.8% metals basis

Application Protocols

No application protocols are specified for this item. If using silica micropowder as a stationary phase or support, follow method-specific literature or internal SOPs. Examples (literature/general, not item-specific):

• Flash chromatography: Determine loading by TLC scouting; pre-adsorb crude on silica for improved band shape; pack column wet with eluent; collect fractions and analyze by TLC/LC. Scale particle size to balance resolution and backpressure.
• Scavenging/workup: Stir reaction mixture with silica or functionalized silica; filter through a pad of silica or celite; rinse with appropriate solvent. Validate recovery and impurity removal by LC/GC/MS.
• Supported catalysis: Prepare supported catalyst (impregnation or covalent tethering); conduct reaction under conditions recommended for the catalyst; filter and recycle support as appropriate.

For nucleic acid binding or filtration roles, consult validated kits/protocols suited to the specific silica surface area/chemistry—parameters not provided for this listing.

Biological Roles

Item-specific biological data are not provided. The following are literature/general observations regarding silica in biological contexts:

• Biosilicification: Many organisms (e.g., diatoms, radiolarians, sponges, and some plants) biomineralize silica to form intricate frustules/spicules. This process polymerizes monomeric silicic acid (Si(OH)4) under biological control, yielding hydrated amorphous silica.
• Plant physiology: Plants uptake silicic acid from soil; deposition as phytoliths can enhance mechanical strength and stress tolerance. These forms are amorphous and distinct from crystalline mineral quartz.
• Biocompatibility: Amorphous silica nanoparticles and microparticles are widely studied as carriers and adjuvants; surface chemistry (silanol density, porosity, functionalization) governs protein adsorption and cellular interactions. These are research contexts, not product-specific claims.
• Toxicology context: Respirable crystalline silica is associated with lung disease upon chronic exposure, whereas amorphous silica is generally considered to have lower chronic toxicity—yet can still cause irritation at high exposures. The crystallinity of this item is not specified; adopt prudent handling to minimize inhalation.
• Enzymatic/affinity uses: Silica surfaces bind nucleic acids in the presence of chaotropes (e.g., guanidinium salts), a principle used in solid-phase extraction. Performance depends on surface area, porosity, and silanol availability—parameters not specified here.

Note: This product is for research use only and is not intended for food, cosmetic, or clinical applications.

Buffer Applications

Silica micropowder is an inorganic solid and does not function as a classical buffering agent. Therefore, conventional buffer preparation (defined pKa, pH range, ionic strength) is not applicable.

Related practical notes (literature/general):

• In nucleic acid purification, silica-based solid phases are used within chaotropic salt buffers to bind DNA/RNA; the buffer system (e.g., guanidinium thiocyanate with ethanol) governs adsorption/desorption. Performance depends on surface area/porosity and is protocol-specific, not specified for this item.
• For chromatographic stationary phases, eluents rather than buffers are selected in normal-phase work. In HILIC or reversed-phase on silica-based bonded phases, buffered aqueous-organic systems are common, but those require defined bonded chemistries not indicated for this item.

If you require a buffering agent, select an appropriate small-molecule buffer (e.g., phosphate, Tris, HEPES) with a pKa near your target pH. For solid-phase applications, consult method-specific protocols and the item’s CoA to verify suitability.

Green Alternatives

Silica is an abundant, noncombustible, and largely inert inorganic material with broad utility. Selection of a greener alternative depends on the function (adsorbent, filter aid, stationary phase, rheology modifier). The table and notes below summarize literature/industry comparisons; they are not item-specific specifications.

Comparison (literature/general):

• Silica (SiO2): High polarity; readily available; reusable after calcination (energy-intensive); dust control needed; avoid HF. Common for normal-phase separations and as catalyst support.
• Alumina (Al2O3): Basic/neutral/acidic grades available; sometimes more robust to moisture in chromatography; may promote side reactions for acid-sensitive substrates.
• Cellulose-based media: Renewable, biodegradable; useful for chiral separations (derivatized phases) or as filter aids; generally lower capacity for highly polar adsorption compared to silica.
• Diatomaceous earth (kieselguhr): Natural silica-based filter aid with large particle size and low pressure drop; limited adsorption selectivity vs chromatographic silica.
• Polymer resins (e.g., polystyrene-divinylbenzene): Recyclable by solvent washing; tunable functionality; lower density and different swelling behavior; temperature limitations.

Greener practice suggestions:

• Minimize silica consumption by optimizing TLC/flash conditions (steeper gradients, higher-efficiency smaller particles, or alternative purification strategies such as crystallization).
• Regenerate spent silica by solvent washing and thermal treatment where appropriate, observing energy and emissions trade-offs.
• For workup/filtration, consider reusable filter media (sintered glass, fabric filters) when adsorption selectivity is not required.
• Evaluate aqueous biphasic extraction or membrane separations before resorting to large-scale silica chromatography to reduce solid waste.

Pharmaceutical Uses

No pharmacopeial grade or excipient designation is specified for this item; consult the CoA/Spec Sheet for suitability. The following are literature/industry roles of silica in pharmaceutical manufacturing and formulation (not specific to this product):

• Colloidal silicon dioxide (amorphous) is widely used as a glidant, anti-caking agent, and rheology modifier in solid oral dosage forms, improving powder flow and preventing clumping. Typical use levels are low (e.g., 0.1–1% w/w), with performance depending on surface area and particle size.
• As a carrier: Porous silica can adsorb liquids (oils, lipids, flavors) to convert them into free-flowing powders (“solidification of liquids”), facilitating blending and tableting.
• As a processing aid: Filter aids based on silica/diatomaceous earth assist in clarification of process streams.
• Silica-based chromatographic media are used in API/intermediate purification at development scale; selection is driven by loadability, particle size, and pore size for the targeted compound.
• Regulatory context: Pharmacopeias (e.g., USP–NF, Ph. Eur.) include monographs for Colloidal Silicon Dioxide and Silicon Dioxide with defined purity and heavy metal limits. Meeting those monographs requires item-specific testing and documentation; this item’s compliance is not stated.

Important: This catalog entry is for research use only. Do not use in human or veterinary applications unless separately qualified to the relevant pharmacopeial/quality standards.

Physical Properties

Item-specific specifications are not provided with this listing. Consult the CoA/Spec Sheet for certified values. The following are typical literature/general properties of silicon dioxide (silica) to aid method planning:

• Appearance: White to off-white fine powder (literature/general for silica micropowders). Not specified for this item; refer to CoA/Spec Sheet.
• Density: ~2.20 g/cm³ (amorphous) to ~2.65 g/cm³ (quartz) at 25 °C (literature).
• Melting/softening: Softening ~1200–1500 °C; melting ~1710 °C (quartz) (literature). Amorphous silica does not exhibit a sharp melting point.
• Boiling/decomposition: Sublimes/decomposes >2000 °C (literature).
• Solubility: Insoluble in water and most organic solvents; reacts/dissolves in hydrofluoric acid and hot concentrated solutions of fluorides to form hexafluorosilicate (literature). Slowly attacked by hot strong bases (e.g., NaOH) to form silicates.
• Refractive index (bulk fused SiO2): nD ~1.458 at 589 nm (literature). Powders exhibit effective refractive behavior depending on packing/porosity.
• Surface area: Highly formulation-dependent (e.g., fumed silica 50–400 m²/g; precipitated/gel silica spans 100–1000+ m²/g) (literature). Not specified for this item; refer to CoA/Spec Sheet.
• Particle size: Micropowder typically denotes sub-100 µm primary aggregates/agglomerates; exact distribution not specified for this item.
• pKa (surface silanols): Apparent acidity varies; reported pKa values for silanol populations often around ~4.5–5.5 (acidic) and ~8.5–9.5 (weakly acidic) depending on hydration and site type (literature/computational models). These are not discrete molecular pKa values.
• Thermal stability: Stable under ambient conditions; dehydroxylation increases with heating above ~200–400 °C (literature).

Quality and Grades

• Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.

Context for silica materials (literature/industry):

• Form/type: Silica micropowders may be amorphous (fumed/pyrogenic or precipitated) or crystalline (e.g., ground quartz). Performance and safety profiles differ—amorphous grades are typical for rheology control and chromatography supports; crystalline grades are typical mineral fillers.
• Chromatography grade: Defined by controlled particle size distribution, pore diameter (e.g., 60, 100, 120 Å), high surface area (e.g., 300–600 m²/g), low metal content, and consistent silanol acidity—enabling reproducible retention and resolution. If your application is TLC/flash/HPLC support, confirm pore size, particle size (e.g., 5–40 µm), and endcapping status.
• Fumed/pyrogenic silica: Very high surface area (50–400 m²/g), low bulk density, aggregated primary particles ~5–50 nm; used for thixotropy and reinforcement. Moisture content and silanol density influence performance.
• Precipitated/gel silica: Tunable pore structures (mesoporous), often used as desiccants, catalyst supports, and adsorbents.
• Electronic/ultra-trace grades: Controlled alkali/transition metal impurities and particles for semiconductor and analytical applications.
• Stabilizers/additives: Some silica powders are surface-modified (silanized, hydrophobic). If present, these alter wettability and chromatographic selectivity. This item does not specify any surface treatment—verify via CoA.

Recommendation: Align selection with your critical quality attributes (CQAs): particle size distribution, BET surface area, pore volume/diameter, metal content, loss on drying/ignition, and residual silanol acidity. Request the CoA/Spec Sheet for quantitative acceptance criteria.

Reaction and Applications

Applications below are based on literature/general practice for silica micropowders; they are not item-specific specifications.

• Chromatography and purification: Silica is the canonical normal-phase stationary phase for TLC and flash chromatography. Surface silanols provide adsorption/partitioning selectivity for polar compounds. Typical eluent systems: hexanes/EtOAc, DCM/MeOH. Pre-drying or controlled activation improves reproducibility. Particle size and pore size critically determine efficiency and loadability (verify for this item via CoA if intended for chromatography).
• Workup aids and scavengers: Silica can remove residual acids (via hydrogen bonding) and amines (after acidifying silica), adsorb metal salts/oxides, and facilitate filtration by immobilizing gums/tars. Functionalized silicas (e.g., thiol-, amine-, or sulfonic-acid-modified) act as scavengers for Pd, Cu, or electrophiles.
• Catalyst support: High-surface-area silica stabilizes dispersed metals (e.g., Pd/SiO2, Pt/SiO2), metal oxides, or organocatalysts. Thermal pre-treatment tailors silanol density for better anchoring. Used in hydrogenations, oxidations, and acid-catalyzed processes.
• Mild acid catalysis: Surface silanols exhibit weak Brønsted acidity; silica promotes acetalizations, rearrangements, or dehydration under solvent-free or supported protocols, sometimes as SiO2–H2SO4 (sulfuric acid supported on silica) for stronger acidity.
• Desiccation and adsorption: Although dedicated desiccant gels are optimized for water uptake, generic silica surfaces adsorb moisture and polar volatiles; pre-dried silica can act as a mild drying agent for sensitive transformations or during solvent removal in vacuo.
• Composites and rheology: In polymer and coating formulations, micropowder silica functions as matting agent, anti-blocking filler, and rheology/thixotropy modifier (particularly for fumed or surface-treated grades).

Tip: For reproducibility, document activation temperature/time, particle size, and any pre-treatment, as these parameters strongly influence performance.

Reaction Conditions

No item-specific operating limits are provided. The following literature/general conditions illustrate how silica micropowder is used across workflows:

• Flash chromatography/TLC: Use silica appropriate to your target (verify particle and pore sizes). Common eluents: hexanes/EtOAc (0–100%), DCM/MeOH (0–20%), toluene, MTBE. Column conditioning with eluent, careful packing, and dust control are essential. Typical room-temperature operation; pressure as required by particle size and column geometry.
• Supported acid catalysis (SiO2–H2SO4): Prepare by impregnating silica with conc. H2SO4, then drying (safety critical). Reactions such as acetalization or dehydration often proceed at 25–80 °C under solvent-free or low-polarity solvents (e.g., toluene) with catalyst loadings of 5–30 wt% relative to substrate. Work up by filtration to remove the solid.
• Silica-assisted condensations: Aldolizations, Knoevenagel, and heterocycle formations have been reported under microwave/solvent-free conditions using neat reagents on silica at 60–140 °C. Yields and times vary widely; pilot trials recommended.
• Scavenging: Add 0.5–5 wt% silica (or functionalized silica) to reaction mixtures at ambient temperature; stir 10–60 min and filter. Monitor by LC/GC to avoid over-adsorption of product.
• Drying/activation: Heat silica at 120–200 °C for 2–6 h under air or vacuum; cool in a desiccator. Higher temperatures (≥400–800 °C) reduce silanol density and change acidity; apply only if compatible with intended use.
• Catalyst supports: Metal deposition (e.g., incipient wetness impregnation) followed by calcination/reduction typically uses 80–500 °C thermal steps depending on the metal precursor.

Always verify compatibility with your substrate and scale, and consult the SDS/CoA for any limits relevant to this specific item.

Safety and Handling

Item-specific GHS classification, signal word, and hazard statements: Not specified for this item; refer to SDS.

General safety guidance for silica powders (literature/industry practice):

• Primary hazards: Nuisance dust; mechanical eye/skin irritation. Prolonged/repeated inhalation of respirable crystalline silica can cause serious lung disease (silicosis). Amorphous silica is generally considered less hazardous but can still irritate the respiratory tract at high dust levels. This listing does not specify crystallinity—apply conservative controls.
• PPE: Use safety glasses with side shields or goggles, lab coat, and suitable gloves. When handling fine powders or generating dust, use a NIOSH-certified particulate respirator as dictated by risk assessment.
• Engineering controls: Work in a well-ventilated area or fume hood. Avoid aerosolization; handle with gentle techniques. Employ closed transfers or local exhaust for bulk handling.
• Incompatibilities: Reacts with hydrofluoric acid (HF) and fluoride salts in strong acid to form volatile silicon tetrafluoride or soluble fluoro-complexes. Slowly attacked by hot concentrated alkali (NaOH/KOH) to form silicates. Avoid contact with strong dehydrating agents that may generate heat with adsorbed moisture.
• First aid overview: If inhaled—move to fresh air; seek medical advice if symptoms persist. Eye contact—rinse cautiously with water for several minutes; remove contact lenses; seek medical attention if irritation continues. Skin—wash with soap and water. Ingestion—rinse mouth; seek advice if unwell. Always defer to the SDS for authoritative measures.
• Fire/explosion: Noncombustible, inert. Fine dust can obscure vision and deposit on equipment; maintain housekeeping to prevent nuisance accumulations.

Solvent Selection

This product is a solid inorganic oxide, not a solvent. Solvent selection is therefore not directly applicable. However, understanding solvent compatibility is important when using silica as an adsorbent, support, or filler.

General compatibility and polarity (literature/industry):

• Surface polarity: Silica is strongly polar due to surface silanols (≡Si–OH) and hydrogen-bonding sites, favoring adsorption of polar/protic solutes. Surface modification (e.g., trimethylsilylation) reduces polarity.
• Miscibility/chemical resistance: Insoluble in water and in most organic solvents (alcohols, hydrocarbons, ethers, chlorinated solvents, esters, ketones). Swelling is not observed. Avoid hydrofluoric acid, fluoride-containing strong acids, and hot strong bases, which dissolve silica.

When to use silica vs alternatives:

• Choose silica for normal-phase chromatography and for removing polar impurities, metal salts, and residual amines/acids via adsorption. Prefer alumina when basic surfaces are desired or when acid-labile analytes are at risk on silica.
• For filtration/clarification at workup, kieselguhr/diatomaceous earth or filter aids may be preferable due to larger pore structure and reduced fine dusting.
• For rheology control in nonpolar formulations, hydrophobically modified (silanized) silicas may outperform hydrophilic silica.

Practical tips:

• Pre-condition silica with eluent to minimize fines and dusting in columns.
• In moisture-sensitive workflows, dry silica at 120–200 °C to lower surface water and standardize activity; cool in a desiccator before use.
• Verify solvent purity rather than silica compatibility—silica is widely compatible with common organic elution systems (hexanes/ethyl acetate, DCM/MeOH, toluene, etc.).

Storage and Reconstitution

• Storage conditions: Not specified for this item; refer to CoA/Spec Sheet. General guidance for silica powders (literature/industry): store tightly closed in a clean, dry container at ambient temperature; protect from moisture uptake to maintain consistent surface activity; avoid conditions that generate dust. Use secondary containment to control spills of fine powder.
• Shipped in: Normal (per product data).
• Shelf life: Not specified for this item; silica is chemically stable, but performance in adsorption/catalysis can drift with moisture/contaminant exposure. Re-dry before critical uses.
• Reconstitution: Not applicable; solid inorganic powder. If preparing slurries or suspensions (e.g., for column packing), wet with a low-surface-tension solvent (e.g., hexanes, DCM, ethanol depending on application) while minimizing dust generation. Degas slurry to remove trapped air for uniform packing.
• Pre-use activation (optional, literature/general): Dry at 120–200 °C for several hours to reduce physisorbed water; cool in a desiccator before opening. Record activation conditions to ensure reproducibility.
• Incompatibilities during storage: Keep away from hydrofluoric acid, fluoride-containing acids, and strongly basic solutions. Avoid prolonged exposure to acidic/basic vapors that could modify surface chemistry.

Always consult the SDS and the item’s CoA/Spec Sheet for definitive storage and handling instructions specific to this catalog number.

Structure and Identity

• Item name: Silica micropowder (fine particulate SiO2)
• SKU: S131647
• CAS: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular formula: SiO2 (literature/general)
• Molecular weight: 60.0843 g/mol (literature/general)
• SMILES: Not applicable to extended solids; often represented as [SiO2]n (literature/general)
• InChIKey: Not applicable to polymeric/extended network solids (literature/general)

Structural features (literature/general):

• Extended 3D network of corner-sharing SiO4 tetrahedra forming amorphous or crystalline polymorphs (e.g., quartz, cristobalite, tridymite). Micropowder refers to particle-size distribution, typically in the micron range, and does not by itself specify crystallinity or porosity.
• Surface chemistry dominated by silanol (≡Si–OH) groups and siloxane bridges (≡Si–O–Si≡). The balance of isolated, vicinal, and geminal silanols depends on thermal history and hydration. These sites govern adsorption, acidity, and reactivity toward silanization.
• In 2D depiction terms: silicon centers (formal +4) each bonded to four oxygen atoms in tetrahedral geometry; each oxygen bridges two silicons (Si–O–Si) or terminates as –OH at the surface. No discrete molecular entity exists in the bulk.

Notes specific to this item:

• No particle size, surface area, pore structure (nonporous vs mesoporous), or phase (amorphous vs crystalline) is specified for this catalog entry. For precise identity attributes (e.g., BET surface area, median particle size, metal content), consult the item’s CoA/Spec Sheet.
• If your use depends on chromatographic performance or surface reactivity, verify the silica type (fumed/pyrogenic, precipitated, gel/porous) before use.

Synthetic Utility

Silica’s combination of high surface area, tunable porosity, and accessible surface silanols underpins its value in synthesis and process chemistry (literature/general):

• Supported reagents and catalysts: Covalent anchoring via silanization (e.g., trialkoxysilane linkers) enables immobilized bases/acids, organocatalysts, and transition-metal complexes. Benefits include simplified separation, catalyst recycling, and reduced metal leaching when designed properly.
• Workup and purification: As a normal-phase stationary phase, silica affords predictable retention trends driven by polarity and hydrogen bonding. In batch, silica slurries scavenge residual reagents (e.g., excess amines after acylations using acid-activated silica, or thiol-silica to capture soft metals/electrophiles).
• Reaction media and promoters: Neat or solvent-free transforms on silica can accelerate rates via micro-concentration and acid-site catalysis (e.g., acetalizations, rearrangements, deprotections), particularly with modified silica (e.g., SiO2–H2SO4, SiO2–NaHSO4, SiO2–HClO4) where a mineral acid is dispersed on the support.
• Desiccation/activation: Pre-dried silica (120–200 °C) provides a mildly dehydrating surface, useful for shifting equilibria in condensation reactions or for protecting moisture-sensitive intermediates during transfers and filtrations.
• Surface modification chemistry: Reaction of surface silanols with chlorosilanes or alkoxysilanes affords hydrophobic or functionalized surfaces (e.g., –(CH2)n–X), enabling tailored interactions for selective adsorption or as solid-phase synthesis platforms.

Note: Performance hinges on particle size distribution, BET area, pore size/volume, and silanol density—parameters not specified for this item. Calibrate protocols with small-scale trials and document activation history for reproducibility.

Target Specificity

Not applicable. This product is an inorganic micropowder (silica), not a biological targeting reagent (e.g., antibody, ligand, enzyme). No antigen/epitope, species reactivity, clone, or isotype information applies.