Mild and Selective Nitration by Claycop

Mixed Oxide Supported MoO3 Catalyst: Preparation, Characterization and Activities in Nitration of o-xylene

“…With respect to this, solid acid catalysts are potentially more attractive due to their shape selective behavior, non corrosiveness, easy recovery, reusability and environmentally friendly nature. Taking in to the account of this, zeolite beta [4,5], ZSM-5 [5,6], sulfated zirconia [7], sulfuric acid supported on silica [8], clay supported metal nitrates [9], metal exchanged clays [10] etc. have been used and studied for the nitration of aromatic substrates like benzene, toluene, halo-benzene, phenol, anisole and disubstituted benzene [4][5][6][7][8][9][10]11,12].…”

“…Taking in to the account of this, zeolite beta [4,5], ZSM-5 [5,6], sulfated zirconia [7], sulfuric acid supported on silica [8], clay supported metal nitrates [9], metal exchanged clays [10] etc. have been used and studied for the nitration of aromatic substrates like benzene, toluene, halo-benzene, phenol, anisole and disubstituted benzene [4][5][6][7][8][9][10]11,12]. However, some of these catalysts were suffered with need of longer residence time, tedious workup procedures and above all, their expensiveness MoO3 based catalysts are well known and successfully tested for different applications like, trasesterification of dimethyl oxalate with phenol [13], thiophene hydrodesulfurization and 1-cyclohehene hydrogenation [14] and hydroprocessing applications [15].…”

Regioselective dinitration of simple aromatics over zeolite Hβ/nitric acid/acid anhydride systems

“…The production of many industrially important chemicals, such as polyurethanes, agrochemicals, explosives, dyes, pharmaceuticals and fragrances, 29,30 is highly dependent on the use of 2,4-dinitrotouene (2,4-DNT) as a crucial intermediate. Unfortunately, dinitration of toluene with mixed acids provides a mixture of 2,4-and 2,6-dinitrotoluenes with low selectivity (typically, 2,4-/2,6-DNT = 4).…”

“…[31][32][33][34][35][36] For example, 2,4-DNT was produced in 85% yield with a 2,4-:2,6-dinitritoluene ratio of 9 when nitration of toluene was carried out with nitric acid and acetic anhydride over claycop. 29,30 However, the process required a large excess of nitric acid and the use of carbon tetrachloride as a solvent. A better 2,4-/2,6-DNT ratio (14) was reported with nitric acid over a zeolite  catalyst.…”

Heteropolyacids as an efficient and reusable catalytic system for the regiospecific nitration of phenols with metal nitrates

“…Extensive and well-documented reviews have been published about the mechanism [1][2][3] and using various nitrating agents under different conditions , most of them are not usually selective and cause environmental concerns regarding the disposal of large volumes of mixed acids typically employed in this process [26,27]. A mixture of concentrated nitric acid and sulfuric acid is used as the most common nitrating reagent for the nitration of benzene, alkyl benzene, and less reactive aromatic compounds [28,29], highly reactive aromatic compounds, phenols and pyrroles, etc., require mild nitration condition, thus a wide variety of nitration methods have been developed [24,25,30,31]. Conventional methods for the nitration of aromatic compounds utilize a mixture of nitric and sulfuric acids or nitronium tetrafluoroborate.…”