Phenolic sentence example
When heated with concentrated hydrochloric acid the amino group is replaced by the hydroxyl group and the phenolic eurhodols are produced.
They may be prepared by the reduction of nitro compounds in alkaline solution (using zinc dust and alkali, or a solution of an alkaline stannite as a reducing agent); by oxidation of hydrazo compounds; or by the coupling of a diazotized amine and any compound of a phenolic or aminic type, provided that there is a free para position in the amine or phenol.
Hantzsch (Ber., 18 99, 3 2, pp. 59 o, 3089) considers that the oxyazo compounds are to be classed as pseudoacids, possessing in the free condition the configuration of quinone hydrazones, their salts, however, being of the normal phenolic type.
Hewitt has also attacked the problem by brominating the oxyazobenzenes, and has shown that when the hydrobromic acid produced in the reaction is allowed to remain in the system, a brombenzene-azo-phenol is formed, whilst if it be removed (by the addition of sodium acetate) bromination takes place in the phenolic nucleus; consequently the presence of the mineral acid gives the azo compound a pseudo-quinonoid character, which it does not possess if the mineral acid be removed from the sphere of the reaction.
Jochem (Ber., 1901, 34, p. 3337), who arrived at the conclusion that the normal decomposition of diazonium salts by alcohols results in the formation of phenolic ethers, but that an increase in the molecular weight of the alcohol, or the accumulation of negative groups in the aromatic nucleus, diminishes the yield of the ether and increases the amount of the hydrocarbon formed.Advertisement
It dissolves readily in caustic alkalis on account of its phenolic character, and it forms a yellow-coloured di-acetate.
However, there may potentially be changes caused within the phenolic compounds by the processing, which may affect bioavailability.
The other possible circumstances where high exposures may occur is in the use of phenolic resins in foundries.
Naturally occurring salicylates and phenolic compounds are a problem in perhaps half of all cases.
Roobios-also called African red tea; the herb is touted as a rich source of antioxidants, flavanoids, and quartering, luteolin and phenolic acids.Advertisement
Current materials frequently seen in hard hats include polycarbonate, Kevlar, aluminum, phenolic, and plastic.