tert-Butyllithium Chemische Eigenschaften,Einsatz,Produktion Methoden
R-Sätze Betriebsanweisung:
R11:Leichtentzündlich.
R15:Reagiert mit Wasser unter Bildung hochentzündlicher Gase.
R17:Selbstentzündlich an der Luft. Spontaneously flammable in air.
R34:Verursacht Verätzungen.
R51/53:Giftig für Wasserorganismen, kann in Gewässern längerfristig schädliche Wirkungen haben.
R65:Gesundheitsschädlich: kann beim Verschlucken Lungenschäden verursachen.
R66:Wiederholter Kontakt kann zu spröder oder rissiger Haut führen.
R67:Dämpfe können Schläfrigkeit und Benommenheit verursachen.
R50/53:Sehr giftig für Wasserorganismen, kann in Gewässern längerfristig schädliche Wirkungen haben.
R38:Reizt die Haut.
S-Sätze Betriebsanweisung:
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.
S43:Zum Löschen . . . (vom Hersteller anzugeben) verwenden (wenn Wasser die Gefahr erhöht, anfügen: "Kein Wasser verwenden").
S45:Bei Unfall oder Unwohlsein sofort Arzt zuziehen (wenn möglich, dieses Etikett vorzeigen).
S62:Bei Verschlucken kein Erbrechen herbeiführen. Sofort ärztlichen Rat einholen und Verpackung oder dieses Etikett vorzeigen.
S61:Freisetzung in die Umwelt vermeiden. Besondere Anweisungen einholen/Sicherheitsdatenblatt zu Rate ziehen.
S16:Von Zündquellen fernhalten - Nicht rauchen.
S33:Maßnahmen gegen elektrostatische Aufladungen treffen.
Beschreibung
tert-Butyllithium solution (tert-BuLi) is an organolithium compound, used as a strong base in organic chemistry. It facilitates lithium-halogen exchange reaction and also can be employed in the deprotonation of C-H compounds and amines. it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon molecules, including benzene. tert-Butyllithium is available commercially as hydrocarbon solutions; it is not usually prepared in the laboratory. Its synthesis was first reported by R. B. Woodward in 1941.
Chemische Eigenschaften
tert-Butyllithium is a colorless crystalline solid or colourless to pale yellow solution. It is more reactive than n- or sec-butyllithium and has similar properties. However, it is thermally stable. Dixon and co-workers have heated tert-Butyllithium to 100°C for 20 hr with little decomposition.
Verwenden
- There are no commercial uses of t-butyllithium, but it is used as a polymerization initiator and as a metalating agent in the laboratory.
- Alkylating and metalating agent. Reagent for the introduction of the tert-butyl group.
- tert-Butyllithium (t-BuLi) is the most reactive of the commercially available organolithium reagents. It is supplied as a standard solution in hydrocarbon solvents, usually in a bottle sealed with a septum.
synthetische
tert-Butyllithium is not sold in large quantities. The
industrial and laboratory preparations are the same: the reaction of t-butyl chloride with
lithium metal in a hydrocarbon solvent. However, tert-Butyllithium is much more difficult to
produce than the other isomeric butyllithium compounds and some special precautions
must be taken to obtain good yields. Principally, the lithium metal must be finely divided
and must contain several percent sodium. It has also been found that t-butyl alcohol in
the butyl chloride is beneficial. The solvent of choice is pentane. Vigorous reflux is necessary for good yield since it apparently helps to remove lithium chloride from the
surface of the metal, and pentane refluxes at about the optimum temperature. If hexane is
used at the same temperature, a significantly lower yield is obtained.
Application
tert-Butyllithium solution can be used as a strong base in the synthesis of:
Alkyllithium derivatives form alkyl iodides and diiodoalkanes by halogen-lithium exchange reaction.
Inorganic polymer [(LiMo3Se3)n] from [(InMo3Se3)n] by reductive intercalation method.
Adducts of cinnamic acid (1,3- and 1,4-adducts) by reacting with C-C double of cinnamic acid.
Structure and conformation
The crystal structure of tert-butyllithium exists as a tetrameric form, comprising four metallic lithium atoms forming a tetrahedral framework. Each face of this tetrahedron is connected to a tert-butyl group. The tertiary carbon atom of tert-butyl is bonded to three lithium metal atoms, establishing a distinctive bridging arrangement.
tert-Butyllithium Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
