Fumed Silica CAS 112945-52-5

Introduction：Basic information about Fumed Silica CAS 112945-52-5, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.

Fumed Silica Basic information

• Product Name: Fumed Silica
• Synonyms: acticel;SILICA GEL 7G;SILICA GEL 8-20 MESH;SILICA GEL 12-28 MESH;SILICA GEL 100;SILICA GEL 60;SILICA GEL 30;SILICA GEL 60 G
• CAS: 112945-52-5
• MF: O2Si
• MW: 60.08
• EINECS: 231-545-4
• Product Categories: UVCBs-inorganic;metal oxide
• Mol File: 112945-52-5.mol

Fumed Silica Chemical Properties

• Melting point: >1600°C
• density: 2.3 lb/cu.ft at 25 °C (bulk density)(lit.)
• refractive index: n20/D 1.46(lit.)
• solubility: Practically insoluble in organic solvents, water, andacids, except hydrofluoric acid; soluble in hot solutions of alkalihydroxide. Forms a colloidal dispersion with water. For Aerosil,solubility in water is 150 mg/L at 258℃ (pH 7).
• form: powder
• Specific Gravity: 2.2
• Hydrolytic Sensitivity: 5: forms reversible hydrate
• Cosmetics Ingredients Functions: OPACIFYING ABRASIVE BULKING VISCOSITY CONTROLLING ANTICAKING ABSORBENT
• InChI: InChI=1S/O2Si/c1-3-2
• InChIKey: VYPSYNLAJGMNEJ-UHFFFAOYSA-N
• SMILES: [Si](=O)=O
• CAS DataBase Reference: 112945-52-5(CAS DataBase Reference)
• EPA Substance Registry System: Silica, amorphous, fumed, cryst.-free (112945-52-5)

Safety Information

• Safety Statements: 24/25
• WGK Germany: 2
• RTECS: VV7310000
• TSCA: Yes
• HS Code: 28112290
• Storage Class: 13 - Non Combustible Solids

Fumed Silica Usage And Synthesis

Chemical Properties

Amorphous silica, the noncrystalline form of SiO2, is a transparent to gray, odorless, amorphous powder

Chemical Properties

Colloidal silicon dioxide is a submicroscopic fumed silica with aparticle size of about 15 nm. It is a light, loose, bluish-white-colored,odorless, tasteless, amorphous powder.

Uses

Synthetic Amorphous Silica has interesting thickening and thixotropic properties, and an enormous external surface area. It is produced by a vapor phase hydrolysis process using chlorosilanes or substituted silanes such as, silicon tetrachloride in a flame of hydrogen and oxygen. This material is formed and collected in a dry state. This product contains no detectable crystalline silica.

Production Methods

Colloidal silicon dioxide is prepared by the flame hydrolysis ofchlorosilanes, such as silicon tetrachloride, at 18008℃ using ahydrogen–oxygen flame. Rapid cooling from the molten stateduring manufacture causes the product to remain amorphous.

Definition

ChEBI: Silicon dioxide is a silicon oxide made up of linear triatomic molecules in which a silicon atom is covalently bonded to two oxygens.

General Description

Fumed silica may be synthesized by high temperature hydrolysis of SiCl₄ in O₂(N₂)/H₂ flame. It is amorphous in nature and possesses very high specific area. The micro droplets of amorphous silica fuse into a branch and form a chain like agglomerate.

Pharmaceutical Applications

Colloidal silicon dioxide is widely used in pharmaceuticals,cosmetics, and food products. Its small particle sizeand large specific surface area give it desirable flow characteristicsthat are exploited to improve the flow properties of dry powdersin a number of processes such as tableting and capsule filling.
Colloidal silicon dioxide is also used to stabilize emulsions andas a thixotropic thickening and suspending agent in gels andsemisolid preparations. With other ingredients of similar refractiveindex, transparent gels may be formed. The degree of viscosityincrease depends on the polarity of the liquid (polar liquidsgenerally require a greater concentration of colloidal silicon dioxidethan nonpolar liquids). Viscosity is largely independent oftemperature. However, changes to the pH of a system may affectthe viscosity1.
In aerosols, other than those for inhalation, colloidal silicondioxide is used to promote particulate suspension, eliminate hardsettling, and minimize the clogging of spray nozzles. Colloidalsilicon dioxide is also used as a tablet disintegrant and as anadsorbent dispersing agent for liquids in powders. Colloidalsilicon dioxide is frequently added to suppository formulationscontaining lipophilic excipients to increase viscosity, preventsedimentation during molding, and decrease the release rate.Colloidal silicon dioxide is also used as an adsorbent during thepreparation of wax microspheres; as a thickening agent fortopical preparations; and has been used to aid the freeze-dryingof nanocapsules and nanosphere suspensions.

Safety Profile

Poison by intraperitoneal, intravenous, and intratracheal routes. Moderately toxic by ingestion. An inhalation hazard. Much less toxic than crystalhe forms. Questionable carcinogen with experimental carcinogenic data. Mutation data reported. Does not cause silicosis. See also other silica entries

Safety

Colloidal silicon dioxide is widely used in oral and topicalpharmaceutical products and is generally regarded as an essentiallynontoxic and nonirritant excipient. However, intraperitoneal andsubcutaneous injection may produce local tissue reactions and/orgranulomas. Colloidal silicon dioxide should therefore not beadministered parenterally.
LD₅₀ (rat, IV): 0.015 g/kg
LD₅₀ (rat, oral): 3.16 g/kg

Potential Exposure

Amorphous fumed silica is used as a mineral, natural or synthetic fiber. A potential danger to those involved in the production and handling of fumed silica for paint pigments or catalysts. Diatomaceous earth is used in clarifying liquids, in manufacture of fire brick and heat insulators; used as a filtering agent; as a filler in construction materials; pesticides, paints, and varnishes. A potential danger to those involved in mining of diatomaceous earth or fabrication of products there from.

storage

Colloidal silicon dioxide is hygroscopic but adsorbs large quantitiesof water without liquefying. When used in aqueous systems at a pH0–7.5, colloidal silicon dioxide is effective in increasing the viscosityof a system. However, at a pH greater than 7.5 the viscosityincreasingproperties of colloidal silicon dioxide are reduced; and ata pH greater than 10.7 this ability is lost entirely since the silicondioxide dissolves to form silicates. Colloidal silicon dioxidepowder should be stored in a well-closed container.

Purification Methods

Purification of silica for high technology applications uses isopiestic vapour distillation from concentrated volatile acids and is absorbed in high purity water. The impurities remain behind. Preliminary cleaning to remove surface contaminants uses dip etching in HF or a mixture of HCl, H2O2 and deionised water [Phelan & Powell Analyst 109 1299 1984].

Incompatibilities

Silica, amorphous is a noncombustible solid. Generally unreactive chemically. Incompatible with fluorine, oxygen difluoride, chlorine trifluoride. Soluble in molten alkalis and reacts with most metallic oxides at high temperature.

Incompatibilities

Incompatible with diethylstilbestrol preparations.

Toxics Screening Level

The initial threshold screening level (ITSL) for the amorphous silica compounds listed above is 60 μg/m3 based on an 8-hour averaging time.

Waste Disposal

Sanitary landfill.

Regulatory Status

GRAS listed. Included in the FDA Inactive Ingredients Database(oral capsules, suspensions, and tablets; transdermal, rectal, andvaginal preparations). Also approved by the FDA as a food additiveand for food contact. Included in nonparenteral medicines licensedin the UK. Included in the Canadian List of Acceptable NonmedicinalIngredients.

Fumed Silica Preparation Products And Raw materials

• Raw materials: Sulfuric acid-->Methyltrichlorosilane-->Tetrachlorosilane-->Trichlorosilane
• Preparation Products: Sodium silicate-->Calcium phosphate dibasic dihydrate-->Hexafluorosilicic acid-->Sodium fluorosilicate-->Silicon carbide-->Sodium fluoride-->Silica glass-->Magnesium fluorosilicate-->Porcelain glaze,industrial-->Potassium silicate-->piling adhesive YH-891-->Premixing agent-->SODIUM METASILICATE PENTAHYDRATE-->1-OCTADECENE-->LEAD SILICOCHROMATE