- What is Phenol?
- Nomenclature of Phenol.
- Pure sources of Phenol.
What is Phenol?
Phenols are much like alcohols however type stronger hydrogen bonds. Thus, they’re extra soluble in water than are alcohols and have greater boiling points. Phenols happen both as colorless liquids or white solids at room temperature and could also be extremely poisonous and caustic.
Phenols are broadly utilized in family merchandise and as intermediates for industrial synthesis. For instance, phenol itself is used (in low concentrations) as a disinfectant in family cleaners and in mouthwash. Phenol could have been the primary surgical antiseptic. In 1865 the British surgeon Joseph Lister used phenol as an antiseptic to sterilize his working area. With phenol used on this method, the mortality price from surgical amputations fell from 45 to fifteen % in Lister’s ward. Phenol is sort of poisonous, nonetheless, and concentrated options trigger extreme however painless burns of the pores and skin and mucous membranes. Much less-toxic phenols, reminiscent of n-hexylresorcinol, have supplanted phenol itself in cough drops and different antiseptic functions. Butylated hydroxytoluene (BHT) has a lot of decrease toxicity and is a typical antioxidant in meals.
In trade, phenol is used as a beginning material to make plastics, explosives reminiscent of picric acid, and drugs reminiscent of aspirin. The widespread phenol hydroquinone is the part of photographic developer that reduces uncovered silver bromide crystals to black metallic silver. Different substituted phenols are used within the dye trade to make intensely colored azo dyes. Mixtures of phenols (particularly the cresols) are used as elements in wooden preservatives reminiscent of creosote.
Nomenclature of phenols
Many phenolic compounds have been found and used lengthy earlier than chemists have been capable of deciding their constructions. Subsequently, trivial names (i.e., vanillin, salicylic acid, pyrocatechol, resorcinol, cresol, hydroquinone, and eugenol) are sometimes used for the commonest phenolic compounds.
Systematic names are extra helpful, nonetheless, as a result of a scientific title specifies the precise construction of the compound. If the hydroxyl group is the principal purposeful group of phenol, the compound may be named as a substituted phenol, with carbon atom 1 bearing the hydroxyl group. For instance, the systematic title for thymol is 5-methyl-2-isopropyl phenol. Phenols with just one different substituent may be named utilizing both the suitable numbers or the ortho (1,2), meta (1,3), and para (1,4) system. Compounds with different principal purposeful teams may be named with the hydroxyl group as a hydroxy substituent. For instance, the systematic title for vanillin is 4-hydroxy-3-methoxy benzaldehyde.
Pure sources of phenols
Phenols are widespread in nature; examples embrace tyrosine, one of many commonplace amino acids present in most proteins; epinephrine (adrenaline), a stimulant hormone produced by the adrenal medulla; serotonin, a neurotransmitter within the mind; and urushiol, an irritant secreted by poison ivy to forestall animals from consuming its leaves. Most of the extra complicated phenols used as flavorings and aromas are obtained from essential oils of vegetation. For instance, vanillin, the principal flavoring in vanilla, is remoted from vanilla beans, and methyl salicylate, which has an attribute minty style and odor, is remoted from wintergreen. Different phenols obtained from vegetation embrace thymol, remoted from thyme, and eugenol, remoted from cloves.
Phenol, the cresols (methyl phenol), and different easy alkylated phenols may be obtained from the distillation of coal tar or crude petroleum.