Trimethylborat Chemische Eigenschaften,Einsatz,Produktion Methoden
ERSCHEINUNGSBILD
FARBLOSE FLüSSIGKEIT
PHYSIKALISCHE GEFAHREN
Die Dämpfe sind schwerer als Luft und können sich am Boden ausbreiten. Fernzündung möglich.
CHEMISCHE GEFAHREN
Zersetzung beim Verbrennen unter Bildung giftiger Rauche mit Boroxiden. Reagiert mit Oxidationsmitteln. Feuer- und Explosionsgefahr. Reagiert mit Wasser, feuchter Luft und starken Säuren unter Bildung von leichtentzündlichem Methanol und Borsäure.
ARBEITSPLATZGRENZWERTE
TLV nicht festgelegt (ACGIH 2005).
MAK nicht festgelegt (DFG 2006).
AUFNAHMEWEGE
Aufnahme in den Körper durch Inhalation, über die Haut und durch Verschlucken.
INHALATIONSGEFAHREN
Nur ungenügende Angaben vorhanden über die Geschwindigkeit, mit der eine gesundheitsschädliche Konzentration in der Luft beim Verdampfen bei 20°C erreicht wird.
WIRKUNGEN BEI KURZZEITEXPOSITION
WIRKUNGEN BEI KURZZEITEXPOSITION: Der Stoff ist reizend auf die Augen, die Haut und die Atemwege.
LECKAGE
Persönliche Schutzausrüstung: Atemschutzfilter für Dämpfe organischer Verbindungen mit niedrigem Siedepunkt. Ausgelaufene Flüssigkeit möglichst in abdichtbaren Behältern sammeln. Reste mit trockenem Sand oder inertem Absorptionsmittel aufnehmen und an einen sicheren Ort bringen. NICHT in die Kanalisation spülen..
R-Sätze Betriebsanweisung:
R11:Leichtentzündlich.
R21:Gesundheitsschädlich bei Berührung mit der Haut.
R23/25:Giftig beim Einatmen und Verschlucken.
R36/37/38:Reizt die Augen, die Atmungsorgane und die Haut.
R10:Entzündlich.
S-Sätze Betriebsanweisung:
S16:Von Zündquellen fernhalten - Nicht rauchen.
S27:Beschmutzte, getränkte Kleidung sofort ausziehen.
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).
S25:Berührung mit den Augen vermeiden.
S23:Gas/Rauch/Dampf/Aerosol nicht einatmen(geeignete Bezeichnung(en) vom Hersteller anzugeben).
S2:Darf nicht in die Hände von Kindern gelangen.
Chemische Eigenschaften
Water-white moisture-sensitive liquid, fumes in the air. It forms an azeotrope with methanol with an azeotrope of 55°C. Miscible with ether, methanol, hexane, tetrahydrofuran; It is stable in anhydrous state and decomposes into methanol and boric acid in presence of water.
Verwenden
Trimethyl borate is a useful reagent in organic synthesis. It is involved in the production of resins, waxes and paints and acts as a methylation agent. As a boron source, it is used to prepare flame retardants, anti-oxidants and corrosion inhibitors. It reacts with Grignard reagents followed by hydrolysis to prepare boronic acid. It is also used as a precursor of borate esters, which finds application in the Suzuki coupling reaction. It is used as neutron detector gas in the presence of a scintillation counter; as a promoter of diborane reactions.
Application
Trimethyl borate reacts with a Grignard reagent or organolithium compounds to yield dimethyl boronates, which upon subsequent aqueous acid treatment afford corresponding boronic acids. The resultant boronic acids or esters are useful intermediates in various cross-coupling reactions such as Suzuki coupling and Chan-Lam coupling. It is also used in the preparation of sodium borohydride.
Definition
ChEBI: Trimethyl borate is a member of the class of borate esters obtained by the formal condensation of three equivalents of methanol with boric acid.
synthetische
The preparation method of trimethyl borate
1. The direct reaction between boric acid and methanol is as follows:
3CH30H+H3B03→B (OCH3) 3+3H20
Usually the trimethyl borate formed in the reaction forms an azeotrope with excess methanol and is distilled out together, and then the trimethyl borate is obtained by separating the azeotrope.
2. The direct reaction between boron oxide and methanol is as follows:
B203+6CH30H→2B (OCH3) 3+3H20
3. Borax, methanol and sulfuric acid are directly reacted, and the reaction formula is :
Na2B4O7.1OH2O+12CH30H+2H2S04→4B (OCH3)3+2NaHS04+17H20
Reaktionen
Trimethyl borate B(OCH3)3 is a popular borate ester used in organic synthesis.
borate esters are prepared from alkylation of trimethyl borate:
ArMgBr + B(OCH3 )3 → MgBrOCH3 + ArB(OCH3 )2
ArB(OCH3 )2 + 2H2O → ArB(OH)2 + 2 HOCH3
Allgemeine Beschreibung
Trimethyl borate appears as a water-white liquid. Denser than water. Vapors heavier than air. Used as a solvent and fungicide for fruit.
Air & Water Reaktionen
Highly flammable. Rapidly decomposes in water.
Reaktivität anzeigen
Borates, such as Trimethyl borate, behave similarly to esters in that they react with acids to liberate heat along with alcohols and acids. Strong oxidizing acids may cause a vigorous reaction that is sufficiently exothermic to ignite the reaction products. Heat is also generated by the interaction of esters with caustic solutions. Flammable hydrogen is generated by mixing esters/borates with alkali metals and hydrides.
Health Hazard
May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.
Brandgefahr
HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water.
Sicherheitsprofil
Moderately toxic by
ingestion, skin contact, and intraperitoneal
routes. An eye irritant. A very dangerous fire
hazard when exposed to heat, flame, or
oxidizers. Moderately explosive when
exposed to flame. Will react with water or
steam to produce toxic and flammable
vapors. To fight fire, use dry chemical, CO2,
spray, foam. When heated to decomposition
it emits acrid smoke and irritating fumes.
See also ESTERS and BORON
COMPOUNDS.
läuterung methode
Carefully fractionate the borate through a gauze-packed column. Re-distil and collect it in weighed glass vials and seal them. Keep it away from moisture. It undergoes alkyl exchange with alcohols and forms azeotropes, e.g. with MeOH the azeotrope consists of 70% (MeO)3B and 30% MeOH with b 52-54o/760mm, d 0.87. [Charnley et al. J Chem Soc 2288 1952, Gerrard & Lappert Chem Ind (London) 53 1952, Schlesinger et al. J Am Chem Soc 75 213 1953.] It has also been dried with Na and then distilled. [Beilstein 1 IV 1269.]
Trimethylborat Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
Benzofuran-2-boronic acid
8-Quinolineboronic acid
1-Methyl-4-pyrazole boronic acid pinacol ester
4-Isopropylbenzeneboronic acid
2-(Methanesulfonylamino)phenylboronic acid
Isopropenylboronic acid pinacol ester
2-(N,N-DIETHYLAMINOCARBONYL)PHENYLBORONIC ACID
Biphenyl-3-boronic acid
2-FLUOROPHENYLBORONIC ACID
2-ISOPROPOXYPHENYLBORONIC ACID
2-Naphthaleneboronic acid
1-METHYL-1H-INDOLE-5-BORONIC ACID 2,2-DIMETHYL PROPANE DIOL-1,3-CYCLIC ESTER
Benzylboronic acid
4-tert-Butylphenylboronic acid
4-(Methylthio)phenylboronic acid
2,3-Dimethylphenylboronic acid
2,6-Difluorphenol
2,5-Dichlorophenylboronic acid
1,4-Phenylenebisboronic acid
3,5-Dimethylisoxazole-4-boronic acid
2-Fluorophenylboronic acid
3,4-METHYLENEDIOXYPHENYLBORONIC ACID
5-METHOXYBENZOFURAN-2-BORONIC ACID
4-Benzyloxybenzeneboronic acid
Benzo[b]thien-2-ylboronic acid
(4-PHENYLAMINOCARBONYLPHENYL)BORONIC ACID
Natriumtetraphenylborat
2,2'-BITHIOPHENE-5-BORONIC ACID
4-FLUORO-2-NITROPHENYLBORONIC ACID
2-Methoxypyridine-3-boronic acid
2-Benzyloxyphenylboronic acid
4-Cyanophenylboronic acid
3-Methoxymethylphenylboronic acid
3,4,5-Trifluorophenol
4-FLUORO-3-(HYDROXYMETHYL)BENZENEBORONIC ACID
4-(METHOXYCARBONYL)PHENYLBORONIC ACID
4-PHENOXYPHENYLBORONIC ACID
5-Indolylboronic acid
1-Methyl-1H-pyrazole-5-boronic acid pinacol ester
Quinoline-5-boronic acid
