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A solution of 4-nitrophenol appears colorless below pH 5.4 and yellow above pH 7.5. [3] This color-changing property makes this compound useful as a pH indicator . The yellow color of the 4-nitrophenolate form (or 4-nitro phenoxide ) is due to a maximum of absorbance at 405 nm (ε = 18.3 to 18.4 mM −1 cm −1 in strong alkali). [ 4 ]
with the formula HOC 6 H 4 NO 2.Three isomeric nitrophenols exist: . o-Nitrophenol (2-nitrophenol; OH and NO 2 groups are neighboring, a yellow solid.; m-Nitrophenol (3-nitrophenol, CAS number: 554-84-7), a yellow solid (m.p. 97 °C) and precursor to the drug mesalazine (5-aminosalicylic acid).
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]
The following 4 pages are in this category, out of 4 total. This list may not reflect recent changes. Nitrophenol; N. 4-Nitrophenol; P. Picric acid; S. Styphnic acid
Bouin solution is a common picric-acid–containing fixative solution used for histology specimens. [25] It improves the staining of acid dyes, but it can also result in hydrolysis of any DNA in the sample. [26] Picric acid is used in the preparation of Picrosirius red, a histological stain for collagen. [27] [28]
4-nitrophenol 4-monooxygenase (EC 1.14.13.167, pnpA (gene), pdcA (gene)) is an enzyme with systematic name 4-nitrophenol,NAD(P)H:oxygen 4-oxidoreductase (4-hydroxylating, nitrite-forming). [1] This enzyme catalyses the following chemical reaction
In enzymology, a 4-nitrophenol 2-monooxygenase (EC 1.14.13.29) is an enzyme that catalyzes the chemical reaction. 4-nitrophenol + NADH + H + + O 2 4-nitrocatechol + NAD + + H 2 O. The 4 substrates of this enzyme are 4-nitrophenol, NADH, H +, and O 2, whereas its 3 products are 4-nitrocatechol, NAD +, and H 2 O.
PNPP is classified as a chromogenic substrate because of its ability to transform from a colorless compound to a colored compound through a biological mechanism, dephosphorylation. [4] PNPP is used because of its low cost and the rate of the reactions can be measured over a wide range of substrate concentrations because the concentration of the ...