Search results
Results from the WOW.Com Content Network
The phrase ipso nitration was first used by Perrin and Skinner in 1971, in an investigation into chloroanisole nitration. [18] In one protocol, 4-chloro- n -butylbenzene is reacted with sodium nitrite in t -butanol in the presence of 0.5 mol% Pd 2 (dba) 3 , a biarylphosphine ligand and a phase-transfer catalyst to provide 4-nitro- n -butylbenzene.
The nitration product produced on the largest scale, by far, is nitrobenzene. Many explosives are produced by nitration including trinitrophenol (picric acid), trinitrotoluene (TNT), and trinitroresorcinol (styphnic acid). [3] Another but more specialized method for making aryl–NO 2 group starts from halogenated phenols, is the Zinke nitration.
Although discussions of directing groups usually focus on electronic effects (e.g. EWG vs EDGs), steric effect can prove influential. Thus, nitration of toluene gives approximately 2:1 ortho vs para-nitrotoluene. In the case of tert-butylbenzene, however, the selectivity is reversed:73% of the product is 4-nitro-tert-butybenzene]]. [4]
4-Nitrophenol is a product of the enzymatic cleavage of several synthetic substrates such as 4-nitrophenyl phosphate (used as a substrate for alkaline phosphatase), 4-nitrophenyl acetate (for carbonic anhydrase), 4-nitrophenyl-β-D-glucopyranoside and other sugar derivatives which are used to assay various glycosidase enzymes.
The methyl group in toluene is small and will lead the ortho product being the major product. On the other hand, the t-butyl group is very bulky (there are 3 methyl groups attached to a single carbon) and will lead the para product as the major one. Even with toluene, the product is not 2:1 but having a slightly less ortho product.
Synthesis of DNP (right) from phenol and nitric acid via 2-Nitrophenol and 4-Nitrophenol. DNP has the chemical formula HOC 6 H 3 (NO 2) 2. As a solid, it is a yellow, crystalline and has a sweet, musty odor. [1] [2] It sublimates, is volatile with steam, and is soluble in most organic solvents as well as aqueous alkaline solutions. [2]
When phenol is treated with diazomethane in the presence of boron trifluoride (BF 3), anisole is obtained as the main product and nitrogen gas as a byproduct. C 6 H 5 OH + CH 2 N 2 → C 6 H 5 OCH 3 + N 2. Phenol and its derivatives react with iron(III) chloride to give intensely colored solutions containing phenoxide complexes.
It can be prepared by nitration of aniline followed by replacement of the amino group via its diazonium derivative. [2] p-Nitrophenol, yellow solid is a precursor to the rice herbicide fluorodifen, the pesticide parathion, and the human analgesic paracetamol (also known as acetaminophen).