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Kinetic parameter estimation of solvent‐free reactions monitored by 13 C NMR spectroscopy, a case study: Mono‐ and di‐(hydroxy)ethylation of aniline with ethylene carbonate
Author(s) -
Lucchini Vittorio,
Fabris Massimo,
Noè Marco,
Perosa Alvise,
Selva Maurizio
Publication year - 2011
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20532
Subject(s) - aniline , chemistry , alkylation , ethylene carbonate , solvent , dimethyl carbonate , ethylene , kinetics , nuclear magnetic resonance spectroscopy , spectroscopy , organic chemistry , catalysis , physics , electrode , quantum mechanics , electrolyte
The kinetics of solvent‐free reactions can be followed in situ by 13 C nuclear magnetic resonance (NMR) spectroscopy, provided that the reaction mixture can be maintained liquid at the monitoring temperature. The pros and cons of the technique and the correct translation of the signal intensities into concentrations are discussed. A good model for this investigation is the reaction of ethylene carbonate ( 1 ) with aniline ( 2 ) at 140°C, two alkylation products of N ‐mono‐ and N , N ‐bis‐(2‐hydroxy)ethylation of aniline form (compounds 3 and 4 , respectively). The overall reaction occurs with heavy volume shrinking, so that the physical as well as the chemical features evolve during the course of the process. The chemical evolution is described by the kinetic constants k 1 and k 2 of the two N ‐alkylation steps, the physical evolution by the time‐dependent activity coefficients α( t ). Two complementary procedures are utilized for the determination of these parameters. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 154–160, 2011