Abstract
AbstractA study was made of the influence of temperature on the reactions between 1‐fluoro‐2,6‐dinitrobenzene and each of the secondary amines pyrrolidine, piperidine and homopiperidine (hexahydro‐1H‐azepine), carried out in ethyl acetate–chloroform binary solvent mixtures. It involved the analysis of both global activation parameters and the corresponding Arrhenius plots from the kA values at three amine concentrations. These values were obtained by carrying out the reactions at 5, 15, 25, 40 and 50°C over the whole range of chloroform mole fraction. The analysis of Arrhenius lines allowed us to prove the existence of isokinetic relationships, which were used as a diagnostic tool in order to infer a changeover in the nature of the rate‐determining transition state as a function of solvent composition. The experimental evidence together with theoretical quantum mechanical calculations suggest that the reactions with the secondary amines explored carried out in pure ethyl acetate and ethyl acetate–chloroform solvent mixture at X = 0.1 and in some cases also at X = 0.3 proceed via the formation of a six‐membered orientated dipolar aggregate in which the specific base–general acid (SB–GA) mechanism may take place. The reactions carried out in the remaining solvent mixtures evolve towards the classical SB–GA mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
