#butyllithium

[labphoto]

Working with tert-butyllithium. 

This one is a quite useful and well known chemical. It spontaneously ignites on air. tert-Butyllithium is a chemical compound with the formula (CH3)3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon acids, including benzene. tert-Butyllithium is available commercially as hydrocarbon solutions; it is not usually prepared in the laboratory.

tert-Butyllithium is a pyrophoric substance, meaning that it easily catches fire on exposure to air. While it is possible to work with this compound using cannula transfer, traces of tert-butyllithium at the tip of the needle or cannula may catch fire and clog the cannula with lithium salts. Here we transferred it with a plastic syringe under N2 atmosphere. 

Serious laboratory accidents involving tert-butyllithium have occurred, so be careful with this compound!

[labphoto]

Why do we have a beer opener in the lab? 

Well, sometimes larger amounts of butyllithium is needed and it would take too much time to get out everything from a “Aldrich sure seal” bottle through the concrete hard septa with a syringe and needle...

n-Butyllithium, abbreviated BuLi or nBuLi is an organolithium reagent used as a strong base (pKa ≈ 50) in organic chemistry and as a initiator for the anionic polymerization of dienes in polymerchemistry. Due to the large difference between the electronegativities of carbon (2.55) and lithium (0.98), the C-Li bond is highly polarized and the BuLi is highly reactive.

Well, okay, but why was the septa and the fancy bottle? Alkyl-lithium compounds are stored under inert gas to prevent loss of activity and for reasons of safety, since they react with everything, from moisture in the air, CO2, labcoat, skin, face and everything. n-BuLi is not that bad compared to the sec- and tert-BuLi, but it could also ignite easily and it’s really hard to extinguish, since it will probably react with the extinguisher. It is usually handled using air free techniques to prevent mishaps and serious problems, so if you use BuLi, don’t take off the septa, use a needle and argon gas.