Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The "cross" association between butyllithium (BuLi), on the one hand, and oligoisoprenyllithium or oligostyryllithium, on the other, was investigated thermometrically. Dependences of a change in the reaction enthalpy on the ratio of both components were compared with a theoretical assumption that the "mixed" associate consists of trimeric BuLi bound to the unassociated form of "living" oligomers. Thermometric titrations were used to investigate the interaction of "living" oligomers with tetrahydrofuran (THF), 1,2-dimethoxyethane, N,N,N',N'-tetramethylethylenediamine and triethyl amine. GLC analysis of the gas phase in equilibrium with solutions of electrondonors and "living" oligomers allowed the amount of free electrondonor to be determined at various ratios of the two components; the data were used in the determination of the stoichiometric coefficients of the equilibrium reactions under study. THF splits the associated forms of "living" oligomers and forms with them two types of complexes containing one or two THF molecules per one Li atom. All measurements were performed in benzene at 303 K.