3205-31-0Relevant academic research and scientific papers
Kinetics of α-(2,6-Dimethylphenl)vinyllithium: How to Control Errors Caused by Inefficient Mixing with Pairs of Rapidly Competing Ketones
Knorr, Rudolf,Knittl, Monika,Behringer, Claudia,Ruhdorfer, Jakob,B?hrer, Petra
, p. 2843 - 2854 (2017/03/23)
Kinetic studies are a suitable tool to disclose the role of tiny reagent fractions. The title compound 2 reacted in a kinetic reaction order of 0.5 (square root of its concentration) with an excess of the electrophiles ClSiMe3, 1-bromobutane (n-BuBr), or 1-iodobutane (n-BuI) at 32 °C in Et2O or in hydrocarbon solvents. This revealed that the tiny (NMR-invisible) amount of a deaggregated equilibrium component (presumably monomeric 2) was the reactive species, whereas the disolvated dimer 2 was only indirectly involved as a supply depot. Selectivity data (relative rate constants κobs) were collected from competition experiments with the faster reactions of 2 in THF and the addition reactions of 2 to carbonyl compounds. This provided the rate sequences of Et2C=O > dicyclopropyl ketone > t-Bu-C(=O)-Ph > diisopropyl ketone ? t-Bu2C=O > ClSiMe3 > n-BuI > n-BuBr ≈ (bromomethyl)cyclopropane (but t-Bu2C=O 3 in THF only) and also of cyclopropanecarbaldehyde > acetone ≥ t-Bu-CH=O. It is suggested that a deceivingly depressed selectivity (1 obs A/kB), caused by inefficient microscopic mixing of a reagent X with two competing substrates A and B, may become evident toward zero deviation from the correlation line of the usual inverse (1/T) linear temperature dependence of ln κobs.
Identification of organic reaction products in the absence of additivity of chromatographic retention indices. Chloro derivatives of methyl-tert-butyl ketone
Zenkevich,Eliseenkov,Kasatochkin
, p. 505 - 514 (2013/07/26)
As a result of a joint interpretation of mass spectra and gas chromatographic retention indices more than ten products of free radical chlorination of methyl-tert-butyl ketone are identified. They contain from one to six chlorine atoms in the molecule and were not previously characterized either by mass spectrometric or chromatographic reference data. It is found that retention index increments corresponding to a gradual increase in the number of chlorine atoms in the molecule per unit are non-additive and vary in wide ranges (from 53 i.u. to 219 i.u.), which does not hinder the use of separate elements of additive schemes for the estimation of the indices of products of such non-regioselective reactions.
