Octamethylcyclotetrasiloxane CAS 556-67-2
Introduction：Basic information about Octamethylcyclotetrasiloxane CAS 556-67-2, including its chemical name, molecular formula, synonyms, physicochemical properties, and safety information, etc.
Octamethylcyclotetrasiloxane Basic information
| Product Name: | Octamethylcyclotetrasiloxane |
| Synonyms: | JACS-556-67-2;uc7207;unioncarbide7207;vs7207;Octamethylcyclotetrasiloxane,98%;1H-Benzimidazol-2-yl-carbamic Acid Methyl Ester-d4;2-Benzimidazolecarbamic Acid Methyl Ester-d4;BAS-3460-d4 |
| CAS: | 556-67-2 |
| MF: | C8H24O4Si4 |
| MW: | 296.62 |
| EINECS: | 209-136-7 |
| Product Categories: | Organics;Silicon Compounds;Siloxanes;Silicone Series;Self Assembly&Contact Printing;Self-Assembly Materials;Si (Classes of Silicon Compounds);Si-O Compounds;Intermediates & Fine Chemicals;Isotope Labeled Compounds;Pharmaceuticals;Organometallic Reagents;Organosilicon;SilanesOrganometallic Reagents;Chemical Synthesis;Contact Printing;Materials Science;Micro/NanoElectronics;Organometallic Reagents;Self Assembly &Self-Assembly Materials;Silanes;1;556-67-2 |
| Mol File: | 556-67-2.mol |
Octamethylcyclotetrasiloxane Chemical Properties
| Melting point | 17-18 °C (lit.) |
| Boiling point | 175-176 °C (lit.) |
| density | 0.956 g/mL at 25 °C (lit.) |
| vapor density | 1 (vs air) |
| vapor pressure | 1.32hPa at 25℃ |
| refractive index | n |
| Fp | 140 °F |
| storage temp. | Store below +30°C. |
| solubility | <0.001g/l Hydrolysis |
| form | liquid |
| Specific Gravity | 0.956 |
| color | colorless |
| biological source | rabbit |
| explosive limit | 0.4-11.7%(V) |
| Water Solubility | INSOLUBLE |
| Sensitive | Moisture Sensitive |
| Merck | 14,6747 |
| BRN | 1787074 |
| Dielectric constant | 2.4（20℃） |
| Cosmetics Ingredients Functions | SOLVENT SKIN CONDITIONING - EMOLLIENT HAIR CONDITIONING |
| InChI | 1S/C8H24O4Si4/c1-13(2)9-14(3,4)11-16(7,8)12-15(5,6)10-13/h1-8H3 |
| InChIKey | HMMGMWAXVFQUOA-UHFFFAOYSA-N |
| SMILES | C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 |
| LogP | 6.98 at 21.7℃ |
| CAS DataBase Reference | 556-67-2(CAS DataBase Reference) |
| NIST Chemistry Reference | Cyclotetrasiloxane, octamethyl-(556-67-2) |
| EPA Substance Registry System | Octamethylcyclotetrasiloxane (556-67-2) |
Safety Information
| Hazard Codes | Xn |
| Risk Statements | 53-62-10 |
| Safety Statements | 36/37-46-51-61 |
| RIDADR | UN 1993 3/PG 3 |
| WGK Germany | 1 |
| RTECS | GZ4397000 |
| Autoignition Temperature | 400°C |
| TSCA | TSCA listed |
| HazardClass | 3 |
| PackingGroup | III |
| HS Code | 29319090 |
| Storage Class | 3 - Flammable liquids |
| Hazard Classifications | Aquatic Acute 1 Aquatic Chronic 1 Flam. Liq. 3 Repr. 2 |
| Hazardous Substances Data | 556-67-2(Hazardous Substances Data) |
| Toxicity | LD50 oral in rat: 1540mg/kg |
| Chemical Properties | Octamethylcyclotetrasiloxane is also known as D4. It is an odorless, colorless non-oily silicone fluid which has C8H24O4Si4 as chemical formula. It is a cyclic organic silicon substance which can be used as monomer in the production of silicone polymers such as rubber, resins and greases. |
| Uses | Octamethylcyclotetrasiloxane is used as a monomer in the production of silicone polymers and as an intermediate in the production of other organosilicon substances.Further it finds its application in electronics, textiles, personal care products and household care products. Polydimethylsiloxane by the Polymerization of Octamethylcyclotetrasiloxane: To a resin flask equipped with a thermometer, stirrer, and reflux eondenser is added 1000 gm of octamethylcyclotetrasiloxane. The siloxane is heated to 165°C, and then 0.14gm of a potassium hydroxide-isopropanol complex (neutral equivalent = 193.5) is added to give a Si : Κ ratio of 4470:1. In 25 min the stirrer begins to stall, and the polymer is now heated for 3(1/2) hr at 150°C to complete polymerization. The resulting polymer has an intrinsic viscosity of 1.5 dl/gm corresponding to a molecular weight of 804,600. |
| Definition | ChEBI: Octamethylcyclotetrasiloxane is a cyclosiloxane that is the octamethyl derivative of cyclotetrasiloxane. It is an organosilicon compound and a cyclosiloxane. It derives from a hydride of a cyclotetrasiloxane. |
| Preparation | Commercially Octamethylcyclotetrasiloxane is produced from dimethyldichlorosilane. Dimethyldichlorosilane is added dropwise to water, the temperature is maintained at 30-40°C, stratified, the acid water is released, the oily material is hydrolyzed with sodium hydroxide solution, the hydrolysate and 0.5%-2% potassium hydroxide are added to the cracking kettle and cracked at 120-140°C and 99.8 kPa vacuum. The cracked material is fractionated and the fraction is collected at 173-176°C to obtain octamethylcyclotetraoxysilane. |
| General Description | Octamethylcyclotetrasiloxane (D4) is a volatile methylsiloxane (VMS) with a relatively low molecular weight. This silicone fluid has a silicon-oxygen bond in a cyclic arrangement and methyl groups are attached to the silicon atom. D4 can be used in the manufacture of silicone based polymers for use in medical devices and personal care products. |
| Health Hazard | Octamethylcyclotetrasiloxane (D4) can interfere with the body’s hormones. In animals, it can affect the reproductive system. D4 is classified as a category 1 endocrine disruptor by the European Commission. A 2018 study commissioned by the Danish EPA identified D4 as an endocrine disruptor. The Global Harmonized System Label Requirements classified D4 as suspected to produce reproductive toxicity. D4 was added to the Toxic Substances Control Act work plan due to reproductive toxicity, moderate environmental persistence, and high bioaccumulation potential. Adverse reproductive effects including estrogenic effects have been observed in rodents. The European Chemicals Agency characterized D4 as a persistent, bioaccumulative, and toxic chemical, and designated D4 as a Substance of Very High Concern. |
| Flammability and Explosibility | Flammable |
| Safety Profile | A skin irritant. When heated todecomposition it emits acrid smoke and irritating vapors. |
| Purification Methods | The solid exists in two forms, m 16.30o and 17.65o. Dry it over CaH2 and distil it. Further fractionation can be effected by repeated partial freezing and discarding the liquid phase. [Osthoff & Grubb J Am Chem Soc 76 399 1954, Hoffman J Am Chem Soc 75 6313 1953, Beilstein 4 IV 4125.] |
| Toxics Screening Level | The initial threshold screening level (ITSL) for octamethylcyclotetrasiloxane is 75 μg/m3 based on an annual averaging time. |
Octamethylcyclotetrasiloxane Preparation Products And Raw materials
| Raw materials | Dichlorodimethylsilane |
| Preparation Products | Silicone oil-->Dimethoxymethylphenylsilane-->silicone softener RS-->Amino-modified silicone oil-->Dimethicone-->Silicone rubber,methyl RTV 107-->Hydroxy silicone oil emulsion-->Poly(dimethylsiloxane)-->Organosilicon water-proofing agent-->Polydimethylsiloxane, dihydroxy terminated-->Silicone rubber,high temperature-vulcanized mixing-->Silicone oil polyether modified-->Hexamethylcyclotrisiloxane-->1,1,3,3-tetramethyldisiloxane-1,3-diol-->Tetradecamethylcycloheptasiloxane-->DIMETHYLDIFLUOROSILANE-->TETRADECAMETHYLHEXASILOXANE |
