Two-phase nitration of phenols, part 3: The nitration of anisole

Controlled nitration of anisole over HNO3/PO4/MoO3/SiO2/solvent systems

“…Since in the reaction with 65%HNO 3 the amount of 4-nitroanisole slightly increases, it can be suggested that nitrosation in position 4-in the ring is more favorable than in position 2-. Such selectivity is in agreement with results presented by Thompson and Zeegers [6] that in the presence of NO 2 − , greater amounts of 4-nitroanisole are obtained (Table 2). When heterogeneous catalyst is used, the anisole nitration is more effective and the conversion significantly increases in comparison to the un-catalyzed reaction.…”

“…Higher concentration of HNO 2 in the reaction mixture cause the higher amounts of 4-ntroanisole to be formed [6]. (ii) Slightly higher concentration of the strong acidic sites in P/45Mo/Si can cause more effective NO + formation than in the case of P/15Mo/Si.…”

“…(ii) Slightly higher concentration of the strong acidic sites in P/45Mo/Si can cause more effective NO + formation than in the case of P/15Mo/Si. (iii) The greater amount of dehydrated surface molybdates in P/45Mo/Si facilitates binding of water formed in the reaction and prevents HNO 3 from the dilution to the concentration below 55% (anisole nitration occurs with HNO 3 concentration of 55% or greater but almost stops below this concentration [6]). …”

Nitration of phenolic compounds by metal salts impregnated Yb-Mo-montmorillonite KSF

“…1 Nitration of aromatic compounds is one of the most important industrial processes [2][3][4][5][6][7][8][9] and is the subject of a large body of literature. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] In our laboratory, we have been seeking out a more practical process for the nitration of substituted phenols using stoichiometric or a small excess amount of nitric acid under mild conditions because the development of environmentally friendly practical procedures for the nitration of aromatic compounds is highly desirable.…”

Nitration of Phenol and Substituted Phenols with Dilute Nitric Acid Using Phase-Transfer Catalysts

“…Thus, the utility of this processes , are generally low. Besides mixed acids, several other nitrating agents, including concentrated nitric acid, acid anhydrides or triflates, peroxy nitrite, metal nitrates, and nitrogen oxides, have been utilized by many investigators. Catalytic nitration of aromatic hydrocarbons with concentrated nitric acid in the presence of solid acids has received attention with regards to the regioselectivity.…”