On the Positional Reactivity Order in the Sulfonation of Biphenyl and a Series of Oxy Derivatives

Oxidation reaction mechanism of hydrothermal carbon microspheres with applications to transesterification after sulfonation

“…Furthermore, the use of a high concentration of chlorosulfonic acid for sulfonation negated steric hindrance effects and permitted substitution at the methoxy groups at ortho positions on the benzene rings. 9 Therefore, amidation was an important step in the preparation of the SHCMs. The N 1s spectrum generated by the SHCMs contains -N-C O-, -NH 2 and N-S peaks at wileyonlinelibrary.com/jctb 399.9, 400.9 and 405.6 eV, although the -N-C O-peak is shifted to a lower binding energy compared with the AHCMs spectrum.…”

“…However, the 3,3′‐dimethoxybenzidine moieties grafted on the AHCMs each provided more than three sites for sulfonation based on the substitution reactions of –OCH 3 and –NH 2 groups. Furthermore, the use of a high concentration of chlorosulfonic acid for sulfonation negated steric hindrance effects and permitted substitution at the methoxy groups at ortho positions on the benzene rings 9 . Therefore, amidation was an important step in the preparation of the SHCMs.…”

“…Based on a procedure reported by Cerfontain et al ., 9 a 15 mL solution of 5.4 g of chlorosulfonic acid in dichloromethane was added dropwise to a 1 g quantity of AHCMs dispersed in 100 mL of dichloromethane (adding at a rate of 0.0750 mL min −1 ), working under nitrogen at 25 °C. The resulting mixture was stirred for 24 h. Following this, the solid was separated and washed with dichloromethane several times, and then dried at 80 °C for 4 h to afford the SHCMs.…”

“…The use of a high concentration of chlorosulfonic acid for sulfonation negated steric hindrance effects and permitted substitution at the methoxy groups at ortho positions on the benzene rings. 9 As a consequence, 3,3 0 -dimethoxybenzidine provided a total of five possible sulfonation sites so that a solid acid with a high sulfonic acid density was obtained. The sulfonic acid-type hydrothermal carbon microspheres (SHCMs) synthesized in the present study were characterized by qualitative and quantitative analyses of surface elements, determination of acid density and assessments of surface morphologies and thermal stability.…”

“…Compared with p ‐phenylenediamine, each molecule of the former compound provided more than three sites for sulfonation based on the substitution reactions of –OCH 3 and –NH 2 groups. The use of a high concentration of chlorosulfonic acid for sulfonation negated steric hindrance effects and permitted substitution at the methoxy groups at ortho positions on the benzene rings 9 . As a consequence, 3,3′‐dimethoxybenzidine provided a total of five possible sulfonation sites so that a solid acid with a high sulfonic acid density was obtained.…”