Selective Chlorination of Toluene to <I>p</I>-Chlorotoluene Catalyzed by Nanosized Zeolite K-L Catalysts

Abstract

Nanosized zeolite K-L catalysts were synthesized by the hydrothermal method starting from silica sol and potassium aluminate. The crystallinities of the zeolite K-L catalysts increased with increasing the SiO2/Al2O3 mole ratio of reaction solution and prolonging the autoclaving time. Nanosized and well-dispersed zeolite K-L catalysts were synthesized when the SiO2/Al2O3 mole ratio was more than 26:1. Well-crystallized and nanosized zeolite K-L catalysts showed high catalytic activity for the chlorination of toluene to p-chlorotoluene. When the nanosized zeolite K-L catalyst was synthesized with the SiO2/Al2O3 mole ratio of 31:1 at the autoclaving temperature of 150 °C for 96 h, the selectivities of p-chlorotoluene and o-chlorotoluene were 76.2% and 20.0%, respectively, at the complete conversion of toluene.

Dipolar‐Distribution Cavity γ‐Fe2O3@C@α‐MnO2 Nanospindle with Broadened Microwave Absorption Bandwidth by Chemically Etching

“…The Ms values of FCM series are 28.7, 31.7, and 22.4 emu g −1 , respectively (Figure 6b, Hs: 20 000 Oe). The reduction reason is the nonmagnetic α-MnO 2 [44] and the etched magnetic core. Though certain content of γ-Fe 2 O 3 has been etched away, Ms enhancement could be due to the specific shape of remaining core.…”

Chlorination of Toluene to o-Chlorotoluene Catalyzed by Ionic Liquids

“…It was reported that K-L zeolite catalysts could catalyze the toluene chlorination with gaseous Cl 2 at 70-80 • C to o-chlorotoluene with selectivities in a range of 20-49% [6,8]. When NaK-L zeolite catalyzed the toluene chlorination with the use of the expensive SO 2 Cl 2 as the chlorinating agent at 50 • C, p-chlorotoluene was favorably formed with the p-chlorotoluene/o-chlorotoluene ratio of more than 3:1 [7].…”

“…Chlorination of toluene is a typical electrophilic substitution reaction. The methyl group of toluene as the electron-donating substitute can activate the phenyl ring, being beneficial to the electrophilic phenyl chlorination reaction [7,8]. o-Chlorotoluene and p-chlorotoluene are easily formed in the toluene chlorination reaction because methyl is a usual ortho/para directing group.…”

“…The reaction routes in the toluene chlorination with gaseous Cl 2 catalyzed by the ionic liquid catalyst are suggested as Scheme 1. were observed in both samples (Figure 6b), indicating that the [BMIM]Cl-2ZnCl2 ionic liquid catalyst was stable in the chlorination of toluene. It was reported that K-L zeolite catalysts could catalyze the toluene chlorination with gaseous Cl2 at 70-80 °C to o-chlorotoluene with selectivities in a range of 20-49% [6,8]. When NaK-L zeolite catalyzed the toluene chlorination with the use of the expensive SO2Cl2 as the chlorinating agent at 50 °C, p-chlorotoluene was favorably formed with the p-chlorotoluene/o-chlorotoluene ratio of more than 3:1 [7].…”

“…o-Chlorotoluene as an important raw material has been widely used in the production of pharmaceuticals, pesticides, spices, and dyes [1][2][3][4][5]. o-Chlorotoluene has been commercially produced by the chlorination of toluene with gaseous chlorine over conventional Lewis acid catalysts, such as FeCl 3 and AlCl 3 , accompanied by the formation of m-chlorotoluene, p-chlorotoluene, benzyl chloride, and dichlorotoluenes with high yields [6][7][8]. While using FeCl 3 catalyst, only one half of the product is o-chlorotoluene.…”