How to calculate butyllithium strength?

The concentration of butyllithium can be determined by dividing the amount of 2-butanol solution used by 100 µL (the amount of n-butyllithium solution used).

How to calculate n-BuLi?

The moles of n-BuLi used in the titration are equivalent to the moles of diphenylacetic acid used in the reaction. Since the moles of diphenylacetic acid used is known, the calculation of concentration of n-BuLi is given by the following equation: mmol diphenylacetic acid/mL n-BuLi = molarity of n-BuLi solution.

How to quench butyllithium?

Proceed with the quenching of the pyrophoric solution by adding isopropanol slowly to the quenching vessel using a syringe or an addition funnel, under adequate stirring, until no more bubbling Needlestick. Keep the solution cool during the quenching process by controlling the feed rate of the alcohol.

What does n-BuLi do in a reaction?

n-BuLi reacts violently with water: C4H9Li + H2O → C4H10 + LiOH. This is an exergonic reaction. If oxygen is present the butane produced will ignite.

How is the titration of butyllithium done?

Titration of butyllithium (from JOC 1991, 56, 4566): 2,2’-bipyridine (~5 mg) was dissolved in 3 mL of dry ether. n-Butyllithium in hexanes (50 µL) was added, such that a deep red color persisted. A 1.00 M solution of dry 2- butanol in benzene was added dropwise until the color dissipated, forming the yellow dihydropyridine indicator.

How is butyllithium added to a dihydropyridine indicator?

A 1.00 M solution of dry 2- butanol in benzene was added dropwise until the color dissipated, forming the yellow dihydropyridine indicator. n-Butyllithium in hexanes (100 µL) was added to the indicator solution, turning it red. The 2-butanol solution was then added dropwise until the solution turned back to yellow.

When to use n-butyllithium as a base?

N-butyllithium, abbreviated n-BuLi, is an organolithium reagent that is frequently used as a strong base or as a nucleophile. N-butyllithium is commercially available as a solution in alkanes such as hexane or heptane. These solutions are stable when properly stored, but still degrade upon aging and exposure to water or oxygen.

When to add butyl lithium to drop wise?

Add the butyl lithium to the solution drop wise, noting when the first rust-red color appears and persists (this is your first endpoint). Once you have persistent color, add the remainder of the butyl lithium to the flask.