Octamethylcyclotetrasiloxane CAS 556-67-2
CAS number：556-67-2
molecular formula：C8H24O4Si4
molecular weight：296.62
EINECS number：209-136-7
English 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
Related categories
Standard products and standard substances; Silicone; Material intermediates; Siloxane; Silane reagents; Elemental organic compounds; Organic raw materials; Silicone series; Silicon compounds; Organic chemical raw materials; Siloxanes; SiliconeSeries; SiliconCompounds; Organics; ;Si-OCompounds;OrganometallicReagents;Organosilicon;SelfAssembly&ContactPrinting;Self-AssemblyMaterials;SilanesOrganometallicReagents;Organic chemistry; intermediates; chemical raw materials; raw materials; organic chemical raw materials; organic intermediates; pharmaceutical raw materials; dimethylsiloxane mixed rings; organic chemical reagents;Intermediates&FineChemicals;IsotopeLabeledCompounds;Pharmaceuticals;ChemicalSynthesis;ContactPrinting;MaterialsScience;Micro/NanoElectronics;
Introduction
Colorless transparent liquid. Melting point 17.5°C, boiling point 175°C, 74°C (2.66kPa). The relative density is 0.9558 (20/4°C). The refractive index is 1.3968. The flash point is 60°C. Miscible with organic solvents, insoluble in water.
Chemical properties
| Melting point | 17-18°C(lit.) |
| Boiling point | 175-176°C(lit.) |
| Density | 0.956g/mLat25°C(lit.) |
| Vapour density | 1(vsair) |
| Vapor Pressure | 1.32hPaat25℃ |
| Refractive index | n20/D1.396(lit.) |
| Flash point | 140°F |
| Storage conditions | Storebelow+30°C. |
| Solubility | <0.001g/lHydrolysis |
| Shape | liquid |
| Color | colorless |
| Specific gravity | 0.956 |
| Explosive limit value | 0.4-11.7%(V) |
| Water solubility | INSOLUBLE |
| Sensitive | Moisture Sensitive |
| Merck | 14,6747 |
| BRN | 1787074I |
| nChIKey | HMMGMWAXVFQUOA-UHFFFAOYSA-N |
| LogP | 6.98 at 21.7℃ |
| CAS database | 556-67-2(CAS DataBase Reference) |
Colorless transparent liquid. Melting point 17.5°C, boiling point 175°C, 74°C (2.66kPa). The relative density is 0.9558 (20/4°C). The refractive index is 1.3968. The flash point is 60°C. Miscible with organic solvents, insoluble in water.
Use
● The product is silicone oil, an intermediate of silicone rubber.
● Used as a raw material for silicone, also used in the electronics industry
● Used in the manufacture of high tear-resistant silicone rubber products, also used in the synthesis of other polymer compounds
● Used as an intermediate for the preparation of silicone oil, and also used for insulation and moisture resistance of radio parts
Production method
● Add dimethyldichlorosilane dropwise to water, keep the temperature at 30-40°C, separate layers, remove the acidic water, hydrolyze the oil with sodium hydroxide solution, add the hydrolyzate and 0.5%-2% potassium hydroxide for cracking In the kettle, cracking is carried out at 120-140°C and 99.8kPa vacuum. The lysate is subjected to fractional distillation, and fractions at 173-176°C are collected to obtain octamethylcyclotetraoxosilane.
