八甲基环四硅氧烷

Description

Octamethyl cyclotetrasiloxane · CAS 556-67-2 · C8H24O4Si4. UNII CZ227117JE. Boiling Point: 175 °C; Boiling Point: BP: 74 °C at 20 mm Hg; Boiling Point: 175 °C @760 [mm Hg].

Identification

CAS Registry Number	556-67-2
PubChem CID	11169
Molecular formula	C8H24O4Si4
IUPAC name	2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
UNII (FDA)	CZ227117JE

Computed Descriptors

Molecular Weight	296.61
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	0
Exact Mass	296.07516538
Monoisotopic Mass	296.07516538
Topological Polar Surface Area	36.9
Heavy Atom Count	16
Formal Charge	0
Complexity	197

Physical & Chemical Properties

Boiling Point	175 °C
Boiling Point	BP: 74 °C at 20 mm Hg
Boiling Point	175 °C @760 [mm Hg]
Melting Point	17.5 °C
Flash Point	55 °C (131 °F) - closed cup
Flash Point	56 °C
Solubility	In water, 0.056 mg/L at 23 °C
Density	0.9558 @25 °C
Vapor Pressure	1.05 [mmHg]
Vapor Pressure	1.05 mm Hg at 25 °C

Physical description & handling notes

• CBI; Liquid; Liquid; Other Solid
• Colorless liquid; mp = 17.5 deg C; [ICSC]
• COLOURLESS OILY LIQUID.
• Oily liquid
• Smooth, viscous liquid
• In synthetic seawater water, 0.033 mg/L at 25 °C

Regulatory Status

Regulatory & Food Contact	FDA Cumulative Estimated Daily Intake (CEDI): FCS OCTAMETHYLCYCLOTETRASILOXANE (D4) CIR / INCI: Cosmetics ingredient -> Conditioning/Emollient; Moisturizing/Humectant CIR / INCI: Solvent; Emollient; Viscosity controlling; Antistatic; Humectant; Hair conditioning
GHS notification summary	0.1% (2 / 4700)

GHS Hazard Classification

GHS notification summary	0.1% (2 / 4700)
Reported hazard statements	H410, H226 (72.1%), H361 (96%), H413 (89.7%)

Documented Uses

• Used to make methyl silicon oils, silicone fluids, and elastomers; Also used in a variety of applications including fermentation processes, instant coffee production, paper coatings and sizing, diet soft drinks, waste yeast tanks, food washing solutions, adhesives, textiles, de-asphalting, boiler treatments, detergents, cleaning solutions, surfactants, cosmetic products, and polishes; [HSDB]
• Pulp and Paper Processing [Category: Industry]
• Textiles (Fiber & Fabric Manufacturing) [Category: Industry]
• Working with Glues and Adhesives [Category: Other]
• Preparation of methyl silicon oils.
• Field of application: Fuel additives; cleaning/washing agents; impregnation materials; adhesives; binding agents; surface treatment; construction materials; paints; lacquers and varnishes; fillers; reprographic agents; process regulators; anti-set-off; anti adhesive agents. /From table/

Synonyms

OCTAMETHYLCYCLOTETRASILOXANE; 556-67-2; Cyclotetrasiloxane, octamethyl-; 2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane; Oktamethylcyklotetrasiloxan; OMCTS; Cyclic dimethylsiloxane tetramer; Cyclomethicone 4; NUC silicone VS 7207; Union carbide 7207; Silicone SF 1173; DTXSID7027205; KF 994; SF 1173; UC 7207; VS 7207

Frequently Asked Questions

What are the CAS number and molecular formula of Octamethyl cyclotetrasiloxane?

CAS 556-67-2; molecular formula C8H24O4Si4; molecular weight — g/mol.

What other names is Octamethyl cyclotetrasiloxane known by?

OCTAMETHYLCYCLOTETRASILOXANE, 556-67-2, Cyclotetrasiloxane, octamethyl-, 2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane, Oktamethylcyklotetrasiloxan, OMCTS.

What is the regulatory status of Octamethyl cyclotetrasiloxane?

Documented regulatory listings: FDA Cumulative Estimated Daily Intake (CEDI): FCS; OCTAMETHYLCYCLOTETRASILOXANE (D4); CIR / INCI: Cosmetics ingredient -> Conditioning/Emollient; Moisturizing/Humectant.

Is Octamethyl cyclotetrasiloxane classified as hazardous?

0.1% of GHS notifications report no hazard classification (2 of 4700).

What are the key physical properties of Octamethyl cyclotetrasiloxane?

Boiling Point: 175 °C; Boiling Point: BP: 74 °C at 20 mm Hg; Boiling Point: 175 °C @760 [mm Hg]; Melting Point: 17.5 °C.

Facts on this page are taken from PubChem (US National Library of Medicine) and Wikidata. Grade-specific data — assay, moisture, particle size, packaging, shelf life — is issued per batch on the COA and is not published here.