4519-39-5Relevant articles and documents
Preparation method of 2,3-difluorobenzoic acid
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Paragraph 0032; 0037, (2018/11/03)
The invention discloses a preparation method of 2,3-difluorobenzoic acid and belongs to the field of organic chemical synthesis. The method comprises the following steps: taking o-difluoro benzene, carrying out substitution reaction to obtain 2,3-difluorobenzene lithium, then carrying out addition reaction to obtain 2,3-difluorobenzoic acid. Through the preparation method of 2,3-difluorobenzoic acid, the production cost is reduced; the pollution to the environment is reduced; the purity and the yield of the product are improved; and the preparation method has the advantages of easily availableraw materials, simplicity and convenience in operation and capability of being suitable for large-scale industrial production.
Proton transfer equilibria between disubstituted benzoic acids and carbinol base of crystal violet in apolar aprotic solvents. Chemometric analysis of disubstituent effects on the strength of benzoic acid in chlorobenzene
Sen Gupta, Susanta K.,Shrivastava, Ruchi
, p. 369 - 373 (2008/09/19)
Proton transfer equilibria in chlorobenzene between a set of di-substituted (2,3-,2,5-,2,6-, 3,5-dichloro and difluoro) benzoic acids including the corresponding mono-substituted acids and the carbinol base of crystal violet have been studied spectrophotometrically. To investigate the effect of disubstitution at ortho- and/or meta- positions on the strength of benzoic acid, the results have been analysed chemometrically on the basis of Fujita Nishioka's multiparameter approach and the assumption of additivity for substituent effects. The model employed explains 94% of the variance for the disubstituent effects on log K. It is observed that the substituent effect is contributed by ordinary electronic and proximity electronic effects in an almost equal ratio (52:48).
Enzymatic Baeyer-Villiger oxidation of benzaldehydes
Moonen, Marielle J. H.,Westphal, Adrie H.,Rietjens, Ivonne M. C. M.,Van Berkel, Willem J. H.
, p. 1027 - 1034 (2007/10/03)
The selectivity of the chemical Baeyer-Villiger oxidation of benzaldehydes depends on steric and electronic factors, the type of oxidizing agent and the reaction conditions. Here we report on the enzymatic Baeyer-Villiger oxidation of fluorobenzaldehydes
Fragmentation of radical anions of polyfluorinated benzoates
Konovalov, Valery V.,Laev, Sergey S.,Beregovaya, Irina V.,Shchegoleva, Lyudmila N.,Shteingarts, Vitalij D.,Tsvetkov, Yuri D.,Bilkis, Itzhak
, p. 352 - 361 (2007/10/03)
A comprehensive study of the symmetry forbidden fragmentation of short-lived radical anions (RAs) has been undertaken for the complete set of polyfluorinated benzoates (C6FnH5-nCO22, n = 1-5). The decay rate constants (kc) of RAs have been determined in aqueous alkaline solution (pH 13.4) by electron photoinjection (EPI) from mercury electrodes and were found to increase dramatically from ≤3 × 103 s-1 (3-F - C6H4CO2-) to (1.2 ± 0.8) × 109 s-1 (C6F5CO2-). The regioselectivity of C-F bond cleavage in the RA fragmentation has been revealed by structure assignment of reduction products of the polyfluorinated benzoic acids by Na, K, and Zn in liquid NH3, as well as by Zn in aqueous NH3 and aqueous alkaline solutions. The kc values depend on the position of the cleaved fluorine to the CO2- group generally in the order para > ortho > meta, and to sharply increase if adjacent fluorine atoms are present. The observed trends reveal that the kinetics of the RA fragmentation reaction is not controlled by the reaction thermodynamics. Semiempirical UHF/INDO calculations, the validity of which has been confirmed by ab initio ROHF/6-31+G calculations, were done to rationalize the observed trends. The reaction transition state (TS) was considered to arise from the RA's and 2*states crossing avoided due to out-of-plane deviation of the cleaving C-F bond. The satisfactory linear correlation (R = 0.96) between the model reaction energy barrier Ea and log kc has been achieved with modeling the local solvation of the CO2- group by its protonation.
