598-30-1Relevant articles and documents
Complex-Induced Proximity Effects and Dipole-Stabilized Carbanions: Kinetic Evidence for the Role of Complexes in the α'-Lithiations of Carboxamides
Hay, David R.,Song, Zhiguo,Smith, Stanley G.,Beak, Peter
, p. 8145 - 8153 (1988)
The kinetics of the α'-lithiations of N,N-dimethyl-2,4,6-triisopropylbenzamide (4) and N,N-diethyl-2,4,6-triisopropylbenzamide (5) by sec-butyllithium (s-BuLi) in cyclohexane have been investigated.Direct observation of the reactant amide, the intermediate amide-lithium reagent complex(es), and the α'-lithiated products by stopped-flow infrared spectroscopy was used to investigate the initial rate constants as a fuction of reactant concentrations.At constant amide concentration the initial rate constant decreases sharply with increasing concentration of s-BuLi.This behavior is also observed in the presence of tetramethylethylene diamine (TMEDA).The major interaction of TMEDA with s-BuLi in cyclohexane is shown by cryoscopic measurements to be an addition of TMEDA to aggregated s-BuLi.Semiquantitative schemes constructed on the basis of the kinetic data suggest the presence of at least two reactive complexes and that complexes with more ligands are more reactive.The implications of these results are discussed.
Method for industrially producing sec-butyl lithium
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Paragraph 0019; 0026-0030, (2021/12/07)
The invention provides a method for industrially producing sec-butyl lithium. The method for industrially producing sec-butyl lithium comprises (1) replacing air with argon gas in a reaction kettle and adding a solvent. (2) The lithium particles are charged into a feeder, air is replaced with argon, and all the lithium particles are placed in the reaction vessel. (3) On stirring, 2 - chlorobutane and metallic lithium are added dropwise through a metering pump to control the reaction temperature through the reaction kettle jacket and 2 - chlorobutane feeding speed. (4) After incubation 2 - 4h, the reaction is hydraulically introduced into the intermediate tank with argon, and the excess metal lithium is left in the reaction vessel. (5) The material in the intermediate tank was passed to a filter to remove lithium chloride solids with argon gas, and the resulting colorless to pale yellow transparent clear liquid, i.e. sec-butyllithium solution. The method adopts excess metal lithium particles and 2 - chlorobutane in a solvent to react at a certain temperature to produce sec-butyl lithium, so that side reactions are effectively avoided, and the yield is improved.
METHOD FOR PRODUCING ALKYL LITHIUM COMPOUNDS AND ARYL LITHIUM COMPOUNDS BY MONITORING THE REACTION BY MEANS OF IR-SPECTROSCOPY
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Page/Page column 14-15, (2008/06/13)
The invention relates to a method for producing alkyl lithium compounds and aryl lithium compounds by reacting lithium metal with alkyl or aryl halogenides in a solvent, the concentration of the alkyl/aryl halogenide and the alkyl/aryl lithium compound being detected according to an in-line measurement in the reactor by means of IR spectroscopy, and an exact recognition of the end point of the dosing of the halogenide constituents being carried out by evaluation of the IR measurement. Said method enables an optimum reactive process and reaction yield. The identification of the respective concentration of the educt and the product is a reliable reactive process. The yield of the reaction is also optimised by determining the end point of the halogenide dosing, as is the purity of the product due to a lower concentration thereof during the reaction.