Kaolin-assisted Aromatic Chlorination and Bromination

Abstract

1999halogen compounds halogen compounds (benzene compounds) Q 0090 -106Kaolin-Assisted Aromatic Chlorination and Bromination. -Freshly prepared moist kaolin (13 wt.% H 2 O) is found to be an efficient promotor for the highly isomer-selective halogenation of aromatic ethers under conditions (A).

Efficient and facile synthesis of heterocycles and their mechanistic consideration using kaolin

“…25,26 There are an extremely limited number of reactions in the literature in which kaolin-based or kaolin-assisted reactions are reported as catalysts. [27][28][29][30][31][32][33] Kaolin, due to its acidic nature, can be a suitable replacement for various homogeneous catalysts. Kaolin has been used as a solid catalyst in FCC additives, 27 fluid catalytic cracking catalysts, 28 alkylation, 29 the protection reaction of carbonyl compounds, 30 halogenation, 31 biodiesel production, 32 and esterification.…”

“…[27][28][29][30][31][32][33] Kaolin, due to its acidic nature, can be a suitable replacement for various homogeneous catalysts. Kaolin has been used as a solid catalyst in FCC additives, 27 fluid catalytic cracking catalysts, 28 alkylation, 29 the protection reaction of carbonyl compounds, 30 halogenation, 31 biodiesel production, 32 and esterification. 33 Many research groups have developed solvent free syntheses using different catalysts, [34][35][36][37][38][39] but they have some drawbacks such as poor yield, long reaction times, high temperature, microwave and ultrasonication conditions etc.…”

Clay‐catalyzed synthesis of 5‐substituent 1‐H‐tetrazoles

“…Acidic clays are suitable replacement of various homogeneous acid catalysts. They have been used in the synthesis of 1,5-benzodiazepines [23], acetonide protection [24], alkylation of benzene [25], DielsAlder reaction [26], dihydrofuran synthesis [27], and bromination and chlorination of aromatic compounds [28]. In continuing with our research in tetrazole chemistry [29][30][31] and application of clays in organic transformations [32,33], herein we report a new process for synthesis of 1-H-5-substituted tetrazoles using clays as safe, environmentally benign, and inexpensive catalysts.…”