D4 SILOXANE

D4 siloxane = Octamethylcyclotetrasiloxane

CAS Number : 556-67-2 
EC Number  : 209-136-7
ECHA InfoCard : 100.008.307 
PubChem CID   : 11169
ChemSpider    : 10696
Molecular Formula : C8H24O4Si4
Molar mass      : 296.616 g·mol−1
Density              : 0.956 g/mL
Melting point      : 17–18 °C 

Preferred IUPAC name : 
Octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane

Other names
-D4
-D4
-OMCTS

Octamethylcyclotetrasiloxane, also called D4, is an organosilicon compound with the formula [(CH3)2SiO]4. 
D4 siloxane is a colorless viscous liquid. 
D4 siloxane is a common cyclomethicone. 
D4 siloxane is widely used in cosmetics.

Production and polymerization of D4 siloxane
Commercially D4 siloxane is produced from dimethyldichlorosilane. 
Hydrolysis of the dichloride produces a mixture of cyclic dimethylsiloxanes and polydimethylsiloxane. 
From this mixture, the cyclic siloxanes including D4 can be removed by distillation. 
In the presence of a strong base such as KOH, the polymer/ring mixture is equilibrated, allowing complete conversion to the more volatile cyclic siloxanes:

[(CH3)2SiO]4n → n [(CH3)2SiO]4

D4 and D5 are also precursors to the polymer. 
The catalyst is again KOH.

Occurrence of D4 siloxane
D4 siloxane is among the most important of all the cyclic siloxanes, with a global production volume of 136 million kilograms in 1993.
100,000–1,000,000 tonnes per year of D4 is manufactured and/or imported in the European Economic Area.

Safety and environmental considerations of D4 siloxane
D4 siloxane is of low acute toxicity. 
The LC50 for a single four hour inhalation exposure in rats is 36 mg/L. 
The oral LD50 in rats is above 4800 mg/kg and the dermal LD50in rats is above 2400 mg/kg.
As the smallest cyclic dimethylsiloxane that does not experience considerable ring strain,D4 siloxane is one of the most abundant siloxanes in the environment, e.g. in landfill gases.

D4 and D5 have attracted attention because they are pervasive. 
Cyclic siloxanes can be detected in some species of aquatic life.
An independent, peer-reviewed study in the US found "negligible risk from D4 to organisms" while a scientific assessment by the Australian government stated, "the direct risks to aquatic life from exposure to these chemicals at expected surface water concentrations are not likely to be significant."

Use and Manufacturing of D4 siloxane
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]
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.

D4 siloxane has widespread use 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, deasphalting, boiler treatments, detergents, cleaning solutions, surfactants, cosmetic products, and polishes.

Used as a precursor in the production of polydimethylsiloxane polymers, which are widely used in various industrial and consumer applications, topical pharmaceutical formulations and as breast implants; the polymers contain some residual monomers. 
Used in cosmetics as an antistatic, emollient, humectant, solvent, viscosity controller, and hair conditioner. 

Depending on the product type, the concentration of D4 (octamethylcyclotetrasiloxane) in formulations varies between 0.1 and 54%; it is common to use a blend of cyclosiloxanes D4, D5 and D6 in cosmetic products. 
Cyclosiloxane blends containing D4, D5 and D6 are used in the formulation of various types of hair care and skin care products as well as in antiperspirants/deodorants. 4
Certain food products are processed using silicone antifoam containing octamethyltetracyclosiloxane.

Industry Uses of D4 siloxane
-Adhesives and sealant chemicals
-Intermediates
-Lubricants and lubricant additives
-Paint additives and coating additives not described by other categories
-Process regulators
-Solvents (which become part of product formulation or mixture)

Consumer Uses of D4 siloxane
-Adhesives and sealants
-Automotive care products
-Cleaning and furnishing care products
-Paints and coatings
-Personal care products
-Plastic and rubber products not covered elsewhere

Household Products of D4 siloxane
Household & Commercial/Institutional Products
Information on 126 consumer products that contain D4 siloxane in the following categories is provided:
-Auto Products
-Commercial / Institutional
-Hobby/Craft
-Home Maintenance
-Inside the Home
-Personal Care

D4 siloxane 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 siloxane can be used in the manufacture of silicone based polymers for use in medical devices and personal care products.

Application of D4 siloxane
D4 siloxane can be polymerized through ring opening mechanism with a rare earth solid super acid as a catalyst for potential usage in the synthesis of vinyl coated polydimethylsiloxane (PDMS). 
D4 siloxane may also be used as a probe liquid for nuclear magnetic resonance cryoporometry (NMRC) to analyze the pore size distribution (PSD) of oil-bearing tight sandstone. 
Chemical vapor deposition (CVD) of D4 may be utilized for the preparation of siloxane based thin films.

D4 siloxane is used in processing aids, textile applications, cosmetics, toiletries, medical/pharmaceutical preparations, paper coatings, defoamers, paints, coatings, waxes, mechanical fluids, sealants and rubber.
D4 siloxane, also known as cyclotetrasiloxane and Octamethylcyclotetrasiloxane. 
D4 siloxane is an industrial product used in many applications, primarly in cosmetic products and polymers, in its pure form and in mixtures with other siloxanes.  
All silicone polymers have residual of D4, because it is a byproduct of polymerisation.
D4 siloxane was identified as a harmfull compound to the environment, and it may accumulate in living organisms and cause complications.
Government of Canada issued a notice to prevent or limit D4 releases to the environment from industrial effluents. 

D4 siloxane is a common chemical name for octamethylcyclotetra- siloxane. 
The primary use for D4 is to make other silicone chemicals and as an ingredient in some personal care products.

Uses of D4 siloxane
In the draft scope of the D4 siloxane risk evaluation, EPA preliminarily identified conditions of use associated with the manufacture and importing; processing; distribution in commerce; industrial, commercial and consumer uses; and disposal of D4, including:

-In the production of other silicone chemicals;
-In paints and coatings;
-In cleaning, laundry, and dishwashing products; and
-In other commercial and consumer products, including adhesives and sealants, automotive care products, and other plastic and rubber products.

The above listed conditions of use are ways that a person or the environment could be potentially exposed to this chemical. However, when conducting a risk evaluation, EPA also considers the hazards (i.e., health effects or environmental impacts) that could occur from coming in contact with a chemical.

D4 siloxane is a member of the cyclic siloxane, or cyclomethicone, family. 
D4 siloxane is often called simply D4 because of its four dimethylsiloxane units. 
D4 siloxane exists as an oily liquid or low-melting solid.

In 1946, Winton Patnode and Donald F. Wilcock at General Electric (Schenectady, NY) prepared D4 as part of an extensive study of methylpolysiloxanes made by hydrolyzing methylchlorosilanes. In one the many reactions they reported, they mixed dimethyldichlorosilane1 (Me2SiCl2) with large volumes of water to produce a colorless oil with a composition that had an empirical formula close to that of Me2SiO.

Analysis of the oil showed that it was primarily a mixture of cyclic oligomers of the formula (Me2SiO)x, with isolated compounds ranging from x = 3 to x = 10. The relative amounts of each of the cyclosiloxanes varied with hydrolysis conditions such as the Me2SiCl2/H2O ratio and the presence of cosolvents, acids, or bases. 
In general, D4 (x = 4) was the most abundant product.

Today, D4 siloxane is commercially produced by the same general method. 
The product mixture is separated into its components via distillation. 
D4 siloxane and the other oligomers are used to prepare poly(dimethylsiloxane)2 [(Me2SiO)n], familiarly known as silicone oil. 
D4 siloxane itself is used as an additive to plastic and rubber products, paints, adhesives, cosmetics, food packaging, and many other product areas. 
Its worldwide production is in the hundreds of thousands of tonnes.

D4 siloxane based compounds are used in cosmetics to soften, smooth, and moisten. 
They make hair products dry more quickly and deodorant creams slide on more easily. 
They are also used extensively in moisturizers and facial treatments. 
D4 siloxane can also be found in medical implants, water-repelling windshield coatings, building sealants and lubricants.

D4 siloxane is an odorless, colorless non-oily volatile silicone fluid used primarily to make other silicone materials. 
During this process, virtually all of the material is consumed, with only a tiny amount of D4 remaining. 
Additionally, D4 siloxane is a critical substance for electronic component manufacturing.

First aid measures of D4 siloxane

First-aid measures general : 
Remove contaminated clothing and shoes. 
In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible). 
If possible show this sheet; if not available show packaging or label. 
IF exposed or concerned: Get medical advice/attention

First-aid measures after inhalation : 
Remove to fresh air and keep at rest in a position comfortable for breathing. 
If you feel unwell, seek medical advice.

First-aid measures after skin contact : 
Wash with plenty of soap and water.

First-aid measures after eye contact : 
Immediately flush eyes thoroughly with water for at least 15 minutes. 
Remove contact lenses, if present and easy to do. 
Continue rinsing. 
Get medical advice/attention.

First-aid measures after ingestion : 
Never give anything by mouth to an unconscious person. 
Get medical advice/attention.

Substance identity

EC / List no.: 209-136-7
CAS no.: 556-67-2
Mol. formula: C8H24O4Si4

Hazard classification & labelling of D4 siloxane
Warning! According to the harmonised classification and labelling (ATP15) approved by the European Union, this substance is very toxic to aquatic life with long lasting effects and is suspected of damaging fertility.
Additionally, the classification provided by companies to ECHA in REACH registrations identifies that this substance is a flammable liquid and vapour, is suspected of damaging fertility or the unborn child and may cause long lasting harmful effects to aquatic life.

About D4 siloxane
D4 siloxane is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 10 000 to < 100 000 tonnes per annum.
D4 siloxane is used by consumers, in articles, by professional workers (widespread uses), in formulation or re-packing, at industrial sites and in manufacturing.

Consumer Uses of D4 siloxane
D4 siloxane is used in the following products: cosmetics and personal care products, washing & cleaning products, polishes and waxes and inks and toners.
Other release to the environment of this substance is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners) and outdoor use.

Article service life of D4 siloxane
Release to the environment of D4 siloxane can occur from industrial use: industrial abrasion processing with low release rate (e.g. cutting of textile, cutting, machining or grinding of metal) and of articles where the substances are not intended to be released and where the conditions of use do not promote release.
Other release to the environment of this substance is likely to occur from: indoor use in long-life materials with low release rate (e.g. flooring, furniture, toys, construction materials, curtains, foot-wear, leather products, paper and cardboard products, electronic equipment).

D4 siloxane can be found in products with material based on: paper (e.g. tissues, feminine hygiene products, nappies, books, magazines, wallpaper) and leather (e.g. gloves, shoes, purses, furniture).

Widespread uses by professional workers of D4 siloxane
D4 siloxane is used in the following products: cosmetics and personal care products, washing & cleaning products, laboratory chemicals, polishes and waxes and coating products. 
D4 siloxane is used in the following areas: scientific research and development, formulation of mixtures and/or re-packaging and building & construction work. 
D4 siloxane is used for the manufacture of: Other release to the environment of this substance is likely to occur from: indoor use (e.g. machine wash liquids/detergents, automotive care products, paints and coating or adhesives, fragrances and air fresheners) and outdoor use.

Formulation or re-packing of D4 siloxane
D4 siloxane is used in the following products: cosmetics and personal care products, leather treatment products, lubricants and greases and textile treatment products and dyes.
Release to the environment of D4 siloxane can occur from industrial use: formulation of mixtures.

Uses at industrial sites of D4 siloxane
D4 siloxane is used in the following products: laboratory chemicals, non-metal-surface treatment products, polymers, semiconductors, leather treatment products, lubricants and greases and textile treatment products and dyes.
D4 siloxane has an industrial use resulting in manufacture of another substance (use of intermediates).
D4 siloxane is used in the following areas: scientific research and development.
D4 siloxane is used for the manufacture of: chemicals.

Release to the environment of D4 siloxane can occur from industrial use: as an intermediate step in further manufacturing of another substance (use of intermediates), for thermoplastic manufacture, in processing aids at industrial sites and as processing aid.

Manufacture of D4 siloxane
Release to the environment of D4 siloxane can occur from industrial use: manufacturing of the substance.

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
Cyclic dimethylsiloxane tetramer
NUC silicone VS 7207
Oktamethylzyklotetrasiloxan
octamethyl cyclotetrasiloxane
UNII-CZ227117JE
octamethyl-cyclotetrasiloxane
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane
CHEBI:25640
CZ227117JE
OMCTS
DSSTox_CID_7205
DSSTox_RID_78349
DSSTox_GSID_27205
Union carbide 7207
Silicone SF 1173
MFCD00003269
C8H24O4Si4
CAS-556-67-2
CCRIS 1327
HSDB 6131
Oktamethylcyklotetrasiloxan [Czech]
EINECS 209-136-7
KF 994
NSC 345674
SF 1173
UC 7207
VS 7207
BRN 1787074
volasil(tm) 244
bmse000765
EC 209-136-7
SCHEMBL18354
BIDD:ER0157
Dimethylsiloxane Cyclic Tetramer
CHEMBL1869229
DTXSID7027205
HMMGMWAXVFQUOA-UHFFFAOYSA-
Octamethylcyclotetrasiloxane, 98%
Tox21_201398
Tox21_300547
7595AH
CO9810
NSC345674
AKOS008901191
ZINC169743112
MCULE-2162943570
NSC-345674
NCGC00164099-01
NCGC00164099-02
NCGC00164099-03
NCGC00254406-01
NCGC00258949-01
CS-0213747
FT-0688100
O0142
O9810
Octamethylcyclotetrasiloxane, analytical standard
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-
octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
Q2013804
UNII-NMQ347994Z component HMMGMWAXVFQUOA-UHFFFAOYSA-N
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-, homopolymer
2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane #
Cyclomethicone 4, United States Pharmacopeia (USP) Reference Standard
D4 Cyclomethicone, Pharmaceutical Secondary Standard; Certified Reference Material
25037-57-4
Octamethylcyclotetrasiloxane [Wiki]
1787074 [Beilstein]
2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocan [German] [ACD/IUPAC Name]
2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane [ACD/IUPAC Name]
2,2,4,4,6,6,8,8-Octaméthyl-1,3,5,7,2,4,6,8-tétroxatétrasilocane [French] [ACD/IUPAC Name]
209-136-7 [EINECS]
556-67-2 [RN]
CYCLOMETHICONE 4
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl- [ACD/Index Name]
CZ227117JE
D4 Cyclomethicone
GZ4397000
MFCD00003269 [MDL number]
[556-67-2] [RN]
104986-37-0 [RN]
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane; D4
3-Methylbut-2-en-1-ol
4-04-00-04125 [Beilstein]
4-04-00-04125 (Beilstein Handbook Reference) [Beilstein]
83874-62-8 [RN]
C024064
CO9810
cyclic dimethylsiloxane tetramer
cyclotetrasiloxane, octamethyl-
D4
EINECS 209-136-7
NCGC00164099-01
NUC silicone VS 7207
O9810
Octamethyl cyclotetrasiloxane
octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
Octamethylcyclotetrasiloxane D4
Octamethylcyclotetrasiloxane(D4)
octamethyltetrasiloxane
Oktamethylcyklotetrasiloxan
Oktamethylcyklotetrasiloxan [Czech]
Oktamethylzyklotetrasiloxan
OMCTS
Silicone SF 1173
UNII:CZ227117JE
UNII-CZ227117JE
Union carbide 7207
volasil 244
Cyclic dimethylsiloxane tetramer
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-
Cyclotetrasiloxane, octamethyl-
KF 994
NUC silicone VS 7207
Octamethylcyclotetrasiloxane
octamethylcyclotetrasiloxane
Octamethylcyclotetrasiloxane
octamethylcyclotetrasiloxane; [D4]
Oktamethylcyklotetrasiloxan
OMCTS
Silicone SF 1173
UC 7207
Union carbide 7207
VS 7207
octamethylcyclotetrasiloxaan; [D4] (nl)
octamethylcyclotetrasiloxan; [D4] (da)
Octamethylcyclotetrasiloxan; [D4] (de)
octametilciclotetrasiloxan; [D4] (ro)
Octametilciclotetrasiloxano; [D4] (es)
octametilciclotetrassiloxano [D4] (pt)
octaméthylcyclotétrasiloxane; [D4] (fr)
oktamethylcyklotetrasiloxan; [D4] (cs)
oktametilciklotetrasiloksan; [D4] (hr)
oktametilciklotetrasiloksan; [D4] (sl)
oktametilciklotetrasiloksanas; [D4] (lt)
oktametilciklotetrasiloksāns; [D4] (lv)
oktametilciklotetrasziloxán; [D4] (hu)
oktametylcyklotetrasiloksan (no)
oktametylcyklotetrasiloxan; [D4] (sv)
oktametylcyklotetrasiloxán; [D4] (sk)
oktametylocyklotetrasiloksan; [D4] (pl)
oktametyylisyklotetrasiloksaani; [D4] (fi)
Oktametüültsüklotetrasiloksaan; [D4] (et)
ottametilciclotetrasilossano; [D4] (it)
ottametilċiklotetrasiloksan; [D4] (mt)
οκταμεθυλοκυκλοτετρασιλοξάνιο· [D4] (el)
октаметилциклотетрасилоксан; [D4] (bg)
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-
2,2,2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasiloxane
2,2,4,4,6,6,8,8-Octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7,2,4,6,8-tetroxatetrasilocane
2,2,4,4,6,6,8,8-octamethyl-1,3,5,7-tetraoxy-2,4,6,8-tetrasilacyclooctane
cyclosiloxane
Cyclotetrasiloxane, 2,2,4,4,6,6,8,8-octamethyl-
Cyclotetrasiloxane, octamethyl-
Cyclotetrasiloxane,2,2,4,4,6,6,8,8,-octamethyl-
D4
octamethyl-1,3,5,7,2,4,6,8-tetraoxatetrasilocane
octamethylcyclotetra
Octamethylcyclotetrasiloxan
octamethylcyclotetrasiloxan
OCTAMETHYLCYCLOTETRASILOXANE
Octamethylcyclotetrasiloxane
octamethylcyclotetrasiloxane
Octamethylcyclotetrasiloxane
octamethylcyclotetrasiloxane
Octamethylcyclotetrasiloxane, D4
octamethylcyclotetrasiloxane, D4
OctaméthylcyclotetrasiloxaneD4
DOW CORNING(R) 244 FLUID
F-28
F-42S
KF-994
Octame.cy.tetrasil
OCTAMETHYLCYCLOTETRASILOXANE
SF 1173
octomethylcyclotetrasiloxane
SILBIONE TETRAMERE D4
T-07V
T-07v
T-206
TETRAMERE D4
TETRAMERE D4 SP
VS-7207
014-018-00-1
104986-37-0
104986-37-0
117563-66-3
117563-66-3
1257661-59-8
1257661-59-8
556-67-2
83874-62-8
83874-62-8