Tetramethylorthosilicat

Bezeichnung:Tetramethylorthosilicat

CAS-Nr681-84-5

Englisch Name:Tetramethyl orthosilicate

CBNumberCB6177258

SummenformelC4H12O4Si

Molgewicht152.22

MOL-Datei681-84-5.mol

Synonyma

Tetramethylorthosilicat

Tetramethylsilikat

Tetramethylorthosilikat

Tetramethylorthosilicat physikalisch-chemischer Eigenschaften

Schmelzpunkt	−4 °C(lit.)
Siedepunkt	121-122 °C(lit.)
Dichte	1.023 g/mL at 25 °C(lit.)
Dampfdichte	5.25 (vs air)
Dampfdruck	3.35 psi ( 20 °C)
Brechungsindex	n20/D 1.368(lit.)
FEMA	3185 \| METHYLATED SILICA
Flammpunkt	84 °F
storage temp.	Store below +30°C.
Aggregatzustand	liquid
Wichte	1.032
Farbe	colorless
Explosionsgrenze	0.88-23.8%(V)
Wasserlöslichkeit	hydrolysis
Sensitive	Moisture Sensitive
Hydrolytic Sensitivity	7: reacts slowly with moisture/water
BRN	1699658
InChIKey	LFQCEHFDDXELDD-UHFFFAOYSA-N
CAS Datenbank	681-84-5(CAS DataBase Reference)
NIST chemische Informationen	Tetramethyl silicate(681-84-5)
EPA chemische Informationen	Tetramethyl silicate (681-84-5)

Sicherheit

Kennzeichnung gefährlicher	T+
R-Sätze:	10-26-37/38-41
S-Sätze:	16-26-36/37/39-45-28A
RIDADR	UN 2606 6.1/PG 1
WGK Germany	3
RTECS-Nr.	VV9800000
F	10-21
Selbstentzündungstemperatur	245 °C
TSCA	Yes
HazardClass	6.1
PackingGroup	I
HS Code	29209085
Giftige Stoffe Daten	681-84-5(Hazardous Substances Data)

Gefahreninformationscode (GHS)

Tetramethyl orthosilicate Chemische Eigenschaften,Einsatz,Produktion Methoden

ERSCHEINUNGSBILD
FARBLOSE FLüSSIGKEIT
ARBEITSPLATZGRENZWERTE
TLV: 1 ppm (als TWA); (ACGIH 2005).
MAK nicht festgelegt (DFG 2005).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation der Dämpfe und durch Verschlucken.
INHALATIONSGEFAHREN
Beim Verdampfen bei 20°C kann sehr schnell eine gesundheitsschädliche Kontamination der Luft eintreten.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION:
Die Substanz reizt stark die Augen, die Haut und die Atemwege. Inhalation von Dampf kann zu Lungenödem führen (s.Anm.). Die Auswirkungen treten u.U. verzögert ein. ärztliche Beobachtung notwendig.
WIRKUNGEN NACH WIEDERHOLTER ODER LANGZEITEXPOSITION
Möglich sind Auswirkungen auf Nieren und Leber.
LECKAGE
Ausgelaufene Flüssigkeit möglichst in abdichtbaren Behältern sammeln. Reste sorgfältig sammeln. An sicheren Ort bringen. Persönliche Schutzausrüstung: Chemikalienschutzanzug mit umgebungsluftunabhängigem Atemschutzgerät.
R-Sätze Betriebsanweisung:
R10:Entzündlich.
R26:Sehr giftig beim Einatmen.
R37/38:Reizt die Atmungsorgane und die Haut.
R41:Gefahr ernster Augenschäden.
S-Sätze Betriebsanweisung:
S16:Von Zündquellen fernhalten - Nicht rauchen.
S26:Bei Berührung mit den Augen sofort gründlich mit Wasser abspülen und Arzt konsultieren.
S36/37/39:Bei der Arbeit geeignete Schutzkleidung,Schutzhandschuhe und Schutzbrille/Gesichtsschutz tragen.
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
Beschreibung
Tetramethyl orthosilicate is the chemical compound with the formula Si(OCH3)4. This molecule consists of four methoxy groups bonded to a silicon atom.
Two common organic precursors are tetraethyl orthosilicate (TEOS) and tetramethyl orthosilicate (TMOS). The latter is more toxic than the former.
Tetraethyl orthosilicate (TEOS), Si(OC2H5)4, is the first alkoxide of the series, followed by tetramethyl orthosilicate (TMOS), Si(OCH3)4, which is, however, less safe to handle and hydrolyzes faster than TEOS.
The hydrolysis of TMOS is, in fact, around six times faster: in general, a lower hydrolysis rate is associated with an increase of the organic group size in the silicon alkoxide. The properties of the silicon alkoxides change according to the dimension of the alkoxy; larger groups produce an increase in molecular weight, viscosity, and boiling point and a decrease in density of the alkoxides.
As a rule of thumb, a larger size of the alkoxy group is associated with a lower hydrolysis rate due to the steric hindrance. The reactivity follows the sequence, with tetramethyl orthosilicate the most reactive alkoxide:
tetramethyl orthosilicate >tetraethyl orthosilicate>tetra-n-propylorthosilicate>tetrabutyl orthosilicate
Chemische Eigenschaften
Tetramethyl orthosilicate (TMOS), the methyl ester of orthosilicic acid, is a colorless, low-viscosity liquid. It is industrially the most important of the tetraalkyl silicates.
Verwenden
Tetramethyl orthosilicate (TMOS) is popularly used in the sol-gel synthesis of silicates1 and chromium-doped silicates and in the formation of hexagonal mesoporous silica layers.
Verwenden
Tetramethyl Orthosilicate is a compound used in the research of the multifunctionality of silicified nanoshells and the efficiency at adsorbing cadmium ions at cell interfaces.
Verwenden
Coating screens of television picture tubes; mold binders; corrosion-resistant coatings; catalyst preparation; silicone intermediate
Vorbereitung Methode
Silica aerogels are usually prepared by base-catalyzed reaction of tetramethoxysilane or tetraethoxysilane, mostly with ammonia as the catalyst. A modification of this procedure is to prehydrolyze Si(OR)4 with a small amount of water under acidic conditions.
Allgemeine Beschreibung
A clear colorless liquid. Flash point below 125°F. Less dense than water and insoluble in water. Very toxic by ingestion and inhalation and very irritating to skin and eyes. Used to make paints and lacquers.
Air & Water Reaktionen
Flammable. Insoluble in water.
Reaktivität anzeigen
Tetramethyl orthosilicate is incompatible with the following: Oxidizers; hexafluorides of rhenium, molybdenum & tungsten .
Hazard
Eye damage and upper respiratory tract irri-tant.
Health Hazard
TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Bromoacetates and chloroacetates are extremely irritating/lachrymators. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.
Brandgefahr
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water.
Flammability and Explosibility
Flammable
Sicherheitsprofil
Poison by intraperitoneal route. Moderately toxic by inhalation. Midly toxic by skin contact. A severe eye irritant. This material can cause extensive necrosis (experimentally), keratoconus, and opaque cornea. It also causes severe human eye injuries, as well as necrosis of corneal cells, which progresses long after exposure has ceased. It is destructive and its effects resist treatment. Permanent blindness is possible from exposure to it. The kidney seems to be most subject to injury regardless of the mode of exposure. Pulmonary edema has also occurred. This material is more toxic than either ethyl silicate or silicic acid, although it has been thought that the injury caused is largely due to the action of the silicic acid. Flammable when exposed to heat or flame; can react vigorously with oxidizing materials. Potentially violent reaction with metal hexafluorides (e.g., rhenium, molybdenum, tungsten). When heated to decomposition it emits acrid smoke and irritating fumes.
mögliche Exposition
Methyl silicate is used in coating screens of television picture tubes. It may be used in mold binders and in corrosion-resistant coatings; as well as in catalyst preparation and as a silicone intermediate.
Erste Hilfe
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek med-ical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, includ-heart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medi-First Aid: If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek med-ical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, includ-ing resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medi-cal attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 24- 48 h afterbreathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a cortico-steroid spray.
Lager
Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area away from water and moisture. Sources ofignition, such as smoking and open flames, are prohibitedwhere methyl silicate is used, handled, or stored in a manner that could create a potential fire or explosion hazard.
Versand/Shipping
UN2606 Methyl orthosilicate, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 3-Flammable liquid.
läuterung methode
Purification is as for tetraethoxysilane. It has a vapour pressure of 2.5mm at 0o. [IR: Sternbach & MacDiarmid J Am Chem Soc 81 5109 1959. Beilstein 1 IV 1266.]
Inkompatibilitäten
Vapor may form explosive mixture with air. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, including alkaline earth metals, metals, strong acids, strong bases; water, moisture, steam decomposes releasing toxic, flammable gases. Violent reaction with metal hexafluorides of rhenium, molybdenum, and tungsten. Contact with metals may evolve flammable hydrogen gas.

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