22.6: Electrophilic Substitution of Phenols - Chemistry LibreTexts
2020年8月27日 · Direct nitration of phenol (hydroxybenzene) by dilute nitric acid gives modest yields of nitrated phenols and considerable oxidative decomposition to tarry materials; aniline (aminobenzene) is largely destroyed. Bromination of both phenol and aniline is difficult to control, with di- and tri-bromo products forming readily.
Nitration and Sulfonation Reactions In Electrophilic Aromatic …
2018年4月30日 · The key reagent for nitration is nitric acid, HNO 3. By itself, nitric acid is a relatively slow-acting electrophile, especially in the presence of a poor nucleophile such as benzene. [Note – in the case of phenol and other aromatic rings with strongly activating groups, HNO 3 by itself is sufficient for nitration].
Electrophilic Substitution Reactions of Phenols - Nitration ...
Phenols upon treatment with dilute nitric acid undergo nitration at low temperature (298 K) to give a mixture of ortho and para nitrophenols. The mixture formed is further separated into ortho and para nitrophenols by steam distillation on the basis of their volatility.
system for the nitration of phenol, and we have investigated a number of different reaction conditions based upon the in situ generation of HNO3 by solid inorganic acidic salts [NaHSO4·H2O, Mg(HSO4)2, pka~2 ] with sodium nitrate. We report here a one-pot heterogeneous procedure for nitration of phenols. Results and Discussion
The mechanisms of nitration of phenol - ScienceDirect
1996年1月1日 · The biphasic procedure, named nitrous acid catalysed nitration of phenol in the literature has been first pointed out by Kagan and coworkers (ref. 7) and has been since, subject to many studies.
2000年8月24日 · The nitration of aromatic compounds may be achieved with many nitrating reagents and is a very useful method in organic synthesis. Nitration of phenol as a special case has been stud-ied using various nitrating agents under different conditions. 1–17Recently, in this connection we have reported the applica-
Nitration Of Phenols Under Mild And Heterogeneous Conditions …
2000年6月30日 · A simple, mild and region-selective method for the nitration of aromatic compounds using sodium nitrate/ sodium nitrite/ dilute nitric acid (6 wt.%) in the presence of bronsted acid-surfactant ...
Nitration Of Phenols Under Mild And Heterogeneous Conditions
2000年11月14日 · We report here a one-pot heterogeneous procedure for nitration of phenols. Phenol (1) and different types of 4-substituted phenols (4) were subjected to a nitration reaction in the presence of inorganic acidic salts [e.g. Mg (HSO 4) 2 (I) or NaHSO 4 ·H 2 O (II)], NaNO 3 (III), and wet SiO 2 (50% w/w) in dichloromethane (Scheme 1 and Scheme 2).
Enzymatic nitration of phenols - ScienceDirect
2001年9月28日 · A method for enzymatic nitration similar to that of van der Vliet et al. [11] has been employed, albeit from a synthetic perspective using soybean peroxidase (SBP) to catalyze the nitration of phenols. Specifically, we describe a generally applicable enzymatic system that can be used to nitrate a variety of water- and organic-soluble phenolic ...
A kinetic study of phenol nitration and nitrosation with nitrous …
2004年10月23日 · We studied the transformation of phenol in the presence of nitrous acid in the dark. The main detected intermediates were 2-nitrophenol, 4-nitrophenol and 4-nitrosophenol. For the first time a kinetic analysis of the reaction in a pH interval relevant to environmental chemistry has been carried out.