Why does phenol have a low pKa?
Why does phenol have a low pKa? Nitro groups are very powerful electron-withdrawing groups. The phenol derivative picric acid has a pKa of 0.25, lower than that of trifluoroacetic acid. Use a resonance argument to explain why picric acid has such a low pKa. Notice that the methoxy group increases the pKa of the phenol group - it makes it less ...
What are examples of phenols?
phenol
- Natural sources of phenols. Phenols are common in nature; examples include tyrosine, one of the standard amino acids found in most proteins; epinephrine (adrenaline), a stimulant hormone produced by the ...
- Nomenclature of phenols. ...
- Physical properties of phenols. ...
- Synthesis of phenols. ...
- Reactions of phenols. ...
What are the medical and Health uses for phenol?
- A) USES: Phenol (also known as carbolic acid and phenic acid) is used in the treatment of localized skin disorders and as a local anesthetic. ...
- B) PHARMACOLOGY: A phenol achieves its affect via several mechanisms.
- C) TOXICOLOGY: In concentrations of 5% or greater, it rapidly denatures all proteins it contacts. ...
What is the difference between phenols and aromatic alcohols?
What is the difference between phenols and aromatic alcohols?
- Phenols change blue litmus red. They are acidic.
- Phenols give white precipitate with bromine water
- Develop characteristic colours (red, violet, green etc) with neutral FeCl3 solution
- They form azo-dyes by coupli
What plants contain phenols?
Cocoa, potato, yam, tomato, kale, Brussels sprouts, broccoli and others dark green leafy and brightly-colored vegetables as well as legumes and cereals, in addition to spices and fruits such as cherries and citrus, are particularly rich in phenolic compounds.
What is the function of phenol?
Phenol is an antiseptic and disinfectant used in a variety of settings. Phenol is an antiseptic and disinfectant. It is active against a wide range of micro-organisms including some fungi and viruses, but is only slowly effective against spores. Phenol has been used to disinfect skin and to relieve itching.
Is phenol toxic to plants?
Phenol levels of less than 250 mg/L could be degraded by "in planta" metabolism; therefore, no significant buildup of phenol nor any toxic effects in plants occurred. With higher levels, phenol was still degraded quickly, but an accumulation in trees accompanied by severe toxic effects occurred.
Why are phenolics important to plants?
Phenolic compounds regulate crucial physiological functions in plants to provide resistance against various biotic and abiotic stress conditions. To protect against UV radiation plants synthesize phenolic acids and flavonoids to scavenge the reactive oxygen species generated due to light stress.
What is the another name of phenol?
noun Chemistry. Also called carbolic acid, hydroxybenzene, oxybenzene, phenylic acid. a white, crystalline, water-soluble, poisonous mass, C6H5OH, obtained from coal tar, or a hydroxyl derivative of benzene: used chiefly as a disinfectant, as an antiseptic, and in organic synthesis.
What are the three uses of phenol?
What is phenol used for?Phenol Injection. Phenol can be injected into your muscles to treat a condition known as muscle spasticity. ... Chemical matrixectomy. Phenol is commonly used in surgeries for ingrown toenails. ... Vaccine preservative.Sore throat spray. ... Oral analgesics. ... Phenol derivatives. ... Phenol liquid. ... Soap and antiseptic.
What are the dangers of phenol?
Exposure to phenol may cause irritation to the skin, eyes, nose, throat, and nervous system. Some symptoms of exposure to phenol are weight loss, weakness, exhaustion, muscle aches, and pain. Severe exposure can cause liver and/or kidney damage, skin burns, tremor, convulsions, and twitching.
What is an example of a phenol?
Phenols are common in nature; examples include tyrosine, one of the standard amino acids found in most proteins; epinephrine (adrenaline), a stimulant hormone produced by the adrenal medulla; serotonin, a neurotransmitter in the brain; and urushiol, an irritant secreted by poison ivy to prevent animals from eating its ...
Is phenol used in pesticides?
Phenol is also used in pesticides, explosives, dyes and textiles production. It is also used as a disinfectant and reagent in chemical analysis. Phenol is synthesized on an industrial scale from coal tar.
Are Essential Oils phenols?
Phenols are a specialised variety of essential oil constituents that feature an alcohol group attached to an aromatic benzene ring. An aromatic benzene ring is a six-carbon ring structure with three double bonds.
What is the meaning of phenolic?
noun. Definition of phenolic (Entry 2 of 2) 1 : a usually thermosetting resin or plastic made by condensation of a phenol with an aldehyde and used especially for molding and insulating and in coatings and adhesives. — called also phenolic resin. 2 : phenol sense 2.
Why do plants produce polyphenols?
All plants produce considerable amounts of polyphenols as secondary metabolites, which then serve as flower pigments, protection from UV light, and defense against the plant's being eaten.
What is the functional group of phenol?
The functional group present in phenol is COOH. The functional group present in phenol is COOH.
What is the function of phenol in DNA extraction?
To obtain nucleic acid samples, the cell must be lysed and the nucleic acids separated from all other cell materials. Phenol is a useful compound for breaking down superfluous cell materials that would otherwise contaminate the nucleic acid sample.
What are the uses of phenol class 12?
Uses of phenol It is used as an antiseptic. It is used as a disinfectant in household cleaners. It is used in the preparation of resins, dyes, explosives, lubricants, pesticides, plastics, drugs, etc.
Is phenol an antibiotic?
Among the polyphenols, flavanols, flavonols and phenolic acids possess the highest antibacterial activity thanks to the ability to (1) inhibit bacterial virulence factors such as enzymes and toxins, (2) interact with cytoplasmic membrane (3) suppress biofilm formation and (4) exert a synergistic effect with antibiotics ...
What is phenol used for?
Pure phenol is used in certain medical procedures and as an ingredient in numerous treatments and laboratory applications.
What is the best treatment for ingrown toenails?
Phenol is commonly used in surgeries for ingrown toenails. It’s used on more severe ingrown toenails that don’t respond to other treatments. The phenol, in the form of trichloroacetic acid, is used to stop the nail from growing back.
What is the name of the compound that replaces phenol?
One derivative is n-hexylresorcinol, which can be found in cough drops. The compound, butylated hydroxytoluene (BHT), replaced phenol as a food antioxidant.
What is phenol in plants?
Plant-based compounds containing phenol are known to be antioxidants . This means that they can stop the reaction of free radicals with other molecules in your body, preventing damage to your DNA as well as long-term health effects.
What is phenol derivative?
Phenol derivatives. Phenol-derived compounds have a variety of uses, including: Chemical peels. Phenol in trichloroacetic acid is used to penetrate through layers of skin to get rid of old or damaged skin. Food and cosmetic preservatives.
What is the purpose of phenol chloroform?
The phenol-chloroform mixture separates molecules based on how soluble the tissue sample is in that solution. The pH level of phenol helps separate the DNA and RNA.
How long can you use phenol for throat pain?
But throat sprays and antiseptic liquids shouldn’t be used for more than a couple days at a time. And if you’re having symptoms like fever and vomiting, see a doctor.
What is a nonoxynol?
Nonoxynols. Nonoxynols are ethoxylated alkyl phenols that are synthesized from alkylbenzene nonoxynol by reacting it with ethylene oxide to produce ethylene oxide polymers of various lengths. Each nonoxynol is followed by a number that indicates the approximate number of ethylene oxide groups it contains.
How many compounds are in chlorinated phenols?
Chlorinated phenols constitute a series of 19 compounds composed of mono-, di-, tri-, and tetrachoroisomers and one pentachlorophenol (PCP). Although all of the possible structural isomers are available commercially, only four polychlorinated phenols (2,4-dichloro-, 2,4,5-trichloro-, 2,4,6-trichloro-, and PCP) have been of major industrial significance (Figure 1 ), primarily as pesticides and as intermediates in the synthesis of the widely used chlorophenoxy herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), the two major components of Agent Orange (1–7). The annual worldwide production of chlorinated phenols has been estimated to be about 200,000 tons, while PCP represents about 90,000 tons of that [1,2].
What are phenols used for?
Phenols are used as antiseptics or disinfectants. On contact with the skin, they may result in inflammation. In the body, they may cause disorders of the digestive or nervous system. Among the phenols, chlorophenols resulting from reaction with chlorine are strongly toxic and are used as pesticides.
What is the table XXXII?
Table XXXII. Diethyl Ether Extraction of Phenols from Amylose and Amylopectin 674
What is phenol hydroxyl?
Phenols are the cyclic compounds containing the aromatic ring with the phenyl hydroxyl or its substituted radicals (acid, aldehyde, etc.).
What are the figures in parentheses?
The figures in parentheses relate to extraction with moist diethyl ether. The other extractions were performed with dry diethyl ether.
What is the mechanism of chemical carcinogenesis?
According to this theory, PAHs are activated by microsomal enzymes to proximate and finally ultimate carcinogens, which are characterized by a reactive electrophilic center. These chemicals can then react with nucleophilic sites on macromolecules such as DNA, RNA, and proteins. This results in changes in these molecules that increase the risk of carcinogenesis.
How is chlorobenzene converted to chlorobenzene?
Hydrolysis of chlorobenzene (the Dow process) Benzene is easily converted to chlorobenzene by a variety of methods, one of which is the Dow process. Chlorobenzene is hydrolyzed by a strong base at high temperatures to give a phenoxide salt, which is acidified to phenol.
Why are phenols highly reactive?
Phenols are highly reactive toward electrophilic aromatic substitution, because the nonbonding electrons on oxygen stabilize the intermediate cation. This stabilization is most effective for attack at the ortho or para position of the ring; therefore, the hydroxyl group of a phenol is considered to be activating (i.e., its presence causes the aromatic ring to be more reactive than benzene) and ortho- or para -directing.
How is benzene converted to isopropylbenzene?
Benzene is converted to isopropylbenzene (cumene) by treatment with propylene and an acidic catalyst. Oxidation yields a hydroperoxide ( cumene hydroperoxide ), which undergoes acid-catalyzed rearrangement to phenol and acetone. Although this process seems more complicated than the Dow process, it is advantageous because it produces two valuable industrial products: phenol and acetone.
How much hydrogen bond does phenol form in water?
The ability of phenols to form strong hydrogen bonds also enhances their solubility in water. Phenol dissolves to give a 9.3 percent solution in water, compared with a 3.6 percent solution for cyclohexanol in water.
What was the purpose of the phenol used in 1865?
In 1865 the British surgeon Joseph Lister used phenol as an antiseptic to sterilize his operating field. With phenol used in this manner, the mortality rate from surgical amputations fell from 45 to 15 percent in Lister’s ward.
What is the name of the compound that is attached to a carbon atom?
phenol, any of a family of organic compounds characterized by a hydroxyl (―OH) group attached to a carbon atom that is part of an aromatic ring. Besides serving as the generic name for the entire family, the term phenol is also the specific name for its simplest member, monohydroxybenzene (C 6 H 5 OH), also known as benzenol, or carbolic acid. ...
What is BHT in food?
Butylated hydroxytoluene (BHT) has a much lower toxicity and is a common antioxidant in foods. In industry, phenol is used as a starting material to make plastics, explosives such as picric acid, and drugs such as aspirin.
What is the precursor to polycarbonates?
Condensation with acetone gives bisphenol-A, a key precursor to polycarbonates and epoxide resins. Condensation of phenol, alkylphenols, or diphenols with formaldehyde gives phenolic resins, a famous example of which is Bakelite. Partial hydrogenation of phenol gives cyclohexanone, a precursor to nylon.
What is the route analogous to cumene?
It is oxidized to a hydroperoxide, akin to the production of cumene hydroperoxide. Via the Hock rearrangement, cyclohexylbenzene hydroperoxide cleaves to give phenol and cyclohexanone. Cyclohexanone is an important precursor to some nylons.
What is reduced to benzene when distilled with zinc dust?
Phenol is reduced to benzene when it is distilled with zinc dust or when its vapour is passed over granules of zinc at 400 °C: C 6 H 5 OH + Zn → C 6 H 6 + ZnO. When phenol is reacted with diazomethane in the presence of boron trifluoride (BF 3 ), anisole is obtained as the main product and nitrogen gas as a byproduct.
What is the name of the compound that reacts with dilute nitric acid at room temperature?
Phenol reacts with dilute nitric acid at room temperature to give a mixture of 2-nitrophenol and 4-nitrophenol while with concentrated nitric acid, more nitro groups get substituted on the ring to give 2,4,6-trinitrophenol which is known as picric acid .
How much phenol is in scotch?
Phenol is a measurable component in the aroma and taste of the distinctive Islay scotch whisky, generally ~30 ppm, but it can be over 160ppm in the malted barley used to produce whisky. This amount is different from and presumably higher than the amount in the distillate.
What is the chemical formula for phenol?
Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula C 6 H 5 OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group (−C 6 H 5) bonded to a hydroxy group (−OH). Mildly acidic, it requires careful handling because it can cause chemical burns .
Why is phenol acidic?
Resonance structures of the phenoxide anion. One explanation for why phenol is more acidic than aliphatic compounds containing an -OH group is resonance stabilization of the phenoxide anion by the aromatic ring. In this way, the negative charge on oxygen is delocalized on to the ortho and para carbon atoms through the pi system.
What are the compounds that inhibit amylase?
The chemical constituents extracted from plants, phenolic compounds, can inhibit the absorption of amylase in the treatment of carbohydrate absorption, such as diabetes [16]. There are many fruits and vegetables that contain phenolic compounds, especially, grapes, berries and tomatoes. Phenolic compounds, for instance phenolic acids and flavonoids, could promote health benefits by reducing the risk of metabolic syndrome and the related complications of type 2 diabetes. However, different groups of phenolic compounds have different biological characteristics, and very little is known about the mechanisms by which they could contribute to the prevention of disease; there still is the need for further studies.
What are phenolic compounds?
Phenolic compounds are secondary metabolites, which are produced in the shikimic acid of plants and pentose phosphate through phenylpropanoid metabolization [1]. They contain benzene rings, with one or more hydroxyl substituents, and range from simple phenolic molecules to highly polymerized compounds [2] (Figure 1). In the synthesis of phenolic compounds, the first procedure is the commitment of glucose to the pentose phosphate pathway (PPP) and transforming glucose-6-phosphate irreversibly to ribulose-5-phosphate. The first committed procedure in the conversion to ribulose-5-phosphate is put into effect by glucose-6-phosphate dehydrogenase (G6PDH). On the one hand, the conversion to ribulose-5-phosphate produces reducing equivalents of nicotinamide adenine dinucleotide phosphate (NADPH) for cellular anabolic reactions. On the other hand, PPP also produces erythrose-4-phosphate along with phosphoenolpyruvate from glycolysis, which is then used through the phenylpropanoid pathway to generate phenolic compounds after being channeled to the shikimic acid pathway to produce phenylalanine [3,4] (Figure 2). Phenolics are the most pronounced secondary metabolites found in plants, and their distribution is shown throughout the entire metabolic process. These phenolic substances, or polyphenols, contain numerous varieties of compounds: simple flavonoids, phenolic acids, complex flavonoids and colored anthocyanins [5] (Figure 1). These phenolic compounds are usually related to defense responses in the plant. However, phenolic metabolites play an important part in other processes, for instance incorporating attractive substances to accelerate pollination, coloring for camouflage and defense against herbivores, as well as antibacterial and antifungal activities [6,7,8].
What is reactive oxygen?
Reactive oxygen (ROS) and nitrogen (RNS) species are highly reactive oxidized molecules, including superoxide, peroxide, singlet oxygen, hydroxyl radical, NO and OONO, that are constantly produced under normal cellular conditions, such as during homeostasis and impaired functions, which could lead to cellular damage, like ageing, disease and cell death (modified from Shetty et al., 2004.) [20].
What are the two molecules that are highly reactive?
Reactive oxygen (ROS) and reactive nitrogen species (RNS) are highly reactive oxidized molecules, which are generated constantly by normal cellular conditions, for instance the activity of the mitochondrial respiratory chain and inflammation, which could lead to damage in other biological molecules, like proteins and DNA [17,18,19]. The antioxidant enzymes include superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT), all of them will play a vital role in getting rid of these oxidants and preventing cellular injury (Figure 3).
Does grapeseed extract help with diabetes?
Many studies have associated the increase in the consumption of fruits and vegetables containing high levels of antioxidant compounds with the reduction on the risk of certain chronic diseases, for instance diabetes and cardiovascular diseases [33,34,35]. Some polyphenol-rich foods, for instance grape, grape seed extract, pomegranate juice and cranberry juice, have been reported to play a beneficial part in reducing cardiovascular risk elements in patients with metabolic syndrome and type 2 diabetes. There is a recent study that aimed to test the hypothesis that grapeseed extract (GSE) may improve these markers in high-risk cardiovascular subjects with type 2 diabetes; thirty-two type 2 diabetes mellitus patients in the study, prescribed a diet or oral glucose-lowering agents, received GSE (600 mg/day) or placebo for four weeks in a double-blind randomized crossover trial, and the results indicate that GSE significantly improved markers of inflammation and glycaemia and improved a sole marker of oxidative stress in obese type 2 diabetic subjects at high risk of cardiovascular events over a four-week period, which suggests that it may have a therapeutic role in decreasing cardiovascular risk [36,37]. Berries are considered good sources of phenolic compounds, such as phenolic acids and flavonoids. Phenolic compounds from berry fruits as nutritional interventions could be considered a valuable tool to prevent the development of age-related neurodegenerative diseases by inflammation and decreasing oxidative stress [34].
Which acid has the ability to scavenge OH radicals?
OH radical scavenging ability of gallic and protocatechuic acids.
How does extraction temperature affect phenolic compounds?from sciencedirect.com
Fig. 3.14 described the effect of extraction temperature on the total phenolic compounds extracted from E. cottonii and Gracilaria sp. when the extraction processes were carried out at pressure of 10 MPa. The extracted total phenolic compounds increased obviously with increasing extraction temperature, especially when E. cottonii was fed as a starting material. The amount of total phenolic compounds increased with the increase in extraction temperature from 120°C to 160 and 200°C at the same reaction time. The amount of total phenolic compounds extracted at 200°C was almost twofolds than that obtained at 120°C. The decrease in water solvent viscosity under subcritical conditions, the elevated pressures may help to disrupt the interaction between water and seaweed matrices because of the increase of water diffusion coefficients. Furthermore, the water solvent allowed to penetrate easily into seaweed matrices. This is, of course, a beneficial condition in terms of subcritical water extraction technique where the elevated pressures (∼10 MPa) favored the extraction process. This result also explained that the higher pressures may have higher rupture effect on the macroalgae matrices being extracted ( Dominguez, 2013 ). These results confirmed that despite subcritical water extraction method is the simple process and economical operation, it is applicable method for the separation of phenolic compounds from E. cottonii and Gracilaria sp. and may lead to an advanced plant biomass components extraction technology.
How are bound phenolic compounds formed?from sciencedirect.com
Bound phenolic compounds, however, are formed by the transportation of soluble phenolic compounds to the cell wall, which are then conjugated with cell wall macromolecules such as cellulose and protein via ester and glycosidic bonds, thus, contributing to cell wall formation ( Agati et al., 2012 ).
What are PCs in plants?from sciencedirect.com
Phenolic compounds (PCs) are ubiquitously distributed phytochemicals found in most plant tissues, including fruits and vegetables. They are secondary metabolites synthesized through the shikimic acid and phenylpropanoid pathways. PCs possess numerous bioactive properties and, although they are not nutrients, dietary intake provides health-protective effects, therefore postharvest treatments have been used to enhance or preserve the contents of PCs in fruits and vegetables. This chapter is divided into three sections: in the first, the main groups of PCs found in fruits, vegetables, and other plant foods are described and their main food sources mentioned. The second section details the biosynthetic pathways of the main PCs described in the first section and, finally, the last section describes the effect of different postharvest treatments on the PC contents of fruits and vegetables and the biochemical pathways responsible for these changes.
What are the most abundant phenolic compounds?from sciencedirect.com
The most abundant phenolic compounds in the diet are phenolic acids (benzoic and cinnamic acid derivatives) and flavonoids which account for 60% and 30%, respectively, of total dietary phenolic compounds [7]. These phenolic compounds may be associated with various carbohydrates and organic acids and with one another ( Figure 2; Table 1 ).
What are the different types of phenolic compounds?from sciencedirect.com
Based on their chemical structures, phenolic compounds can be divided into different subgroups, such as phenolic acids, flavonoids, tannins, coumarins, lignans, quinones, stilbens, and curcuminoids. The categories of phenolic compounds and their representative compounds are shown in Fig. 9.3.
What is the linkage of Vitis vinifera?from sciencedirect.com
This linkage is characteristic of Vitis vinifera. The loss of the sugar unit in phenolic glycosides (particularly flavonol 3-glucoside) increases the instability of flavonols. Phenolic aglycones in grapes preferentially link to glucose and are found in greater concentrations in leaves.
Why are phenolic compounds important?from sciencedirect.com
Phenolic compounds have been reported to be present in some vegetable oils, which is very important for the oxidative stability of the polyunsaturated fatty acids (Kochhar, 2002 ). The general analysis for the phenolic compounds was to determine the total phenolic content or use HPLC to identify the specific compound.
What are phenolic compounds?
Phenolics are aromatic benzene ring compounds with one or more hydroxyl groups produced by plants mainly for protection against stress. The functions of phenolic compounds in plant physiology and interactions with biotic and abiotic environments are difficult to overestimate. Phenolics play important roles in plant development, ...
What are the roles of phenolics in agrobacterium?
The roles of plant phenolics in defence and communication during Agrobacterium and Rhizobium infection. Phenolics are aromatic benzene ring compounds with one or more hydroxyl groups produced by plants mainly for protection against stress.
How to measure total phenolic content?
Total phenols (or antioxidant effect) can be measured using the Folin-Ciocalteu reaction. Results are typically expressed as gallic acid equivalents (GAE). Ferric chloride (FeCl 3) test is also a colorimetric assay.
How many phenolic groups are there in a monophenol?
They can therefore be called simple phenols or monophenols, with only one phenolic group, or di- ( bi- ), tri- and oligophenols, with two, three or several phenolic groups respectively.
Why does the cuticle harden?
The hardening of the protein component of insect cuticle has been shown to be due to the tanning action of an agent produced by oxidation of a phenolic substance forming sclerotin. In the analogous hardening of the cockroach ootheca, the phenolic substance concerned is 3:4-dihydroxybenzoic acid ( protocatechuic acid ).
What is naturally occurring phenol?
For the molecule alone, see Phenol. In biochemistry, naturally occurring phenols refers to phenol functional group that is found in natural products. Phenolic compounds are produced by plants and microorganisms.
What are phenols used for?
Some phenols are germicidal and are used in formulating disinfectants. Phenol – the simplest of the phenols.
Why are phenols found in plants?
In some cases of natural phenols, they are present in vegetative foliage to discourage herbivory, such as in the case of Western poison oak.
What is the simplest phenol?
Phenol – the simplest of the phenols. Chemical structure of salicylic acid, the active metabolite of aspirin. Chemical structure of aloe emodin, a diphenol. Quercetin, a typical flavonoid, is a polyphenol. Tannic acid, a typical polyphenol of indeterminate structure. Lignin, is around 25% of the composition of wood.
What is an AIHA ERPG?
AIHA ERPG --American Industrial Hygiene Association's emergency response planning guidelines. ERPG 1 is themaximum airborne concentration below which it is believed nearly all individuals could be exposed up to one hourwithout experiencing other than mild transient adverse health effects or perceiving a clearly defined objectionableodor; ERPG 2 is the maximum airborne concentration below which it is believed nearly all individuals could beexposed up to one hour without experiencing or developing irreversible or other serious health effects that couldimpair their abilities to take protective action.
Is phenol a solid or liquid?
Phenol is a colorless or white solid when it is pure; however, it is usually sold and used as a liquid. (1)The odor threshold for phenol is 0.04 parts per million (ppm), with a strong very sweet odor reported. (1,7)Phenol is very soluble in water and is quite flammable. (2)The chemical formula for phenol is C6H6O and the molecular weight is 94.1 g/mol. (8,9)
Can phenol be detected in urine?
Phenol can be detected in urine; this test can be used to determine whether a person has recently been exposed to phenol or to substances that are changed to phenol in the body. However, no test will tell whether a person has been exposed only to phenol, because many substances are changed to phenol in the body. (1)
Is phenol toxic to humans?
Exposure to phenol may occur from the use of some medicinal products (including throat lozenges andointments). Phenol is highly irritating to the skin, eyes, and mucous membranes in humans after acute(short-term) inhalation or dermal exposures. Phenol is considered to be quite toxic to humans via oralexposure. Anorexia, progressive weight loss, diarrhea, vertigo, salivation, a dark coloration of the urine,and blood and liver effects have been reported in chronically (long-term) exposed humans. Animal studieshave reported reduced fetal body weights, growth retardation, and abnormal development in the offspringof animals exposed to phenol by the oral route. EPA has classified phenol as a Group D, not classifiable asto human carcinogenicity.
Overview
Occurrences
Phenol is a normal metabolic product, excreted in quantities up to 40 mg/L in human urine.
The temporal gland secretion of male elephants showed the presence of phenol and 4-methylphenol during musth.
It is also one of the chemical compounds found in castoreum. This compound is ingested from the plants the beaver eats.
Properties
Production
Uses
The major uses of phenol, consuming two thirds of its production, involve its conversion to precursors for plastics. Condensation with acetone gives bisphenol-A, a key precursor to polycarbonates and epoxide resins. Condensation of phenol, alkylphenols, or diphenols with formaldehyde gives phenolic resins, a famous example of which is Bakelite. Partial hydrogenation of phenol gives cyclohexanone, a precursor to nylon. Nonionic detergents are produced by alkylatio…
History
Phenol was discovered in 1834 by Friedlieb Ferdinand Runge, who extracted it (in impure form) from coal tar. Runge called phenol "Karbolsäure" (coal-oil-acid, carbolic acid). Coal tar remained the primary source until the development of the petrochemical industry. In 1841, the French chemist Auguste Laurent obtained phenol in pure form.
In 1836, Auguste Laurent coined the name "phène" for benzene; this is the root of the word "phen…
Biodegradation
Cryptanaerobacter phenolicus is a bacterium species that produces benzoate from phenol via 4-hydroxybenzoate. Rhodococcus phenolicus is a bacterium species able to degrade phenol as sole carbon source.
Toxicity
Phenol and its vapors are corrosive to the eyes, the skin, and the respiratory tract. Its corrosive effect on skin and mucous membranes is due to a protein-degenerating effect. Repeated or prolonged skin contact with phenol may cause dermatitis, or even second and third-degree burns. Inhalation of phenol vapor may cause lung edema. The substance may cause harmful effects on the central nervous system and heart, resulting in dysrhythmia, seizures, and coma. The kidneys m…