108-95-2 Usage
Chemical Description
Different sources of media describe the Chemical Description of 108-95-2 differently. You can refer to the following data:
1. Phenol is a chemical compound used as a substrate in the enzymatic reaction.
2. Phenol is an aromatic compound that contains a hydroxyl group (-OH) attached to a benzene ring.
3. Phenol is a white crystalline solid used in the production of resins and plastics.
4. Phenol and para-cresol were used in the synthesis of the esters.
5. Phenol and triethylamine were used in the chemical synthesis of other substrates (phosphotriesters 1-5 and 7-18) for the same purpose.
6. Phenol is a precursor to aniline and is converted to aniline using a palladium-catalyzed amination reaction.
7. Phenol is a white crystalline solid with a sweet odor and is used in the production of various chemicals.
Chemical Properties
Different sources of media describe the Chemical Properties of 108-95-2 differently. You can refer to the following data:
1. Phenol is the simplest member of a class of organic compounds possessing a hydroxyl group attached to a benzene ring or to a more complex aromatic ring system.Also known as carbolic acid or monohydroxybenzene, phenol is a colorless to white crystalline material of sweet odor, having the composition C6H5OH, obtained from the distillation of coal tar and as a by-product of coke ovens.Phenol has broad biocidal properties, and dilute aqueous solutions have long been used as an antiseptic. At higher concentrations, it causes severe skin burns; it is a violent systemic poison. It is a valuable chemical raw material for the production of plastics, dyes, pharmaceuticals, syntans, and other products.Phenol melts at about 43°C and boils at 183°C. The pure grades have melting point of 39°C, 39.5°C, and 40°C. The technical grades contain 82%-84% and 90%-92% phenol. The crystallization point is given as 40.41°C. The specific gravity is 1.066. It dissolves in most organic solvents. By melting the crystals and adding water, liquid phenol is produced, which remains liquid at ordinary temperatures. Phenol has the unusual property of penetrating living tissues and forming a valuable antiseptic. It is also used industrially in cutting oils and compounds and in tanneries. The value of other disinfectants and antiseptics is usually measured by comparison with phenol.
2. Phenol, C6H5OH, also known as carbolic acid and phenylic acid, is a white poisonous crystalline solid that melts at 43 °C (110 OF) and boils at 182°C (360 OF). Phenol has a sharp burning taste,a distinctive odor, and it irritates tissue. It is toxic not only by ingestion or inhalation, but also by skin absorption. Phenol is soluble in water,alcohol,and ether. It is used in the production of resins,germicides,weedkillers,pharmaceuticals, and as a solvent in the refining of lubricating oils.
3. Phenol has a strong odor that is sickeningly sweet and irritating. Phenol has powerful disinfectant and sanitizing qualities.
It has been used as a topical anesthetic and antiseptic preservative, reagent and chemical reactant. Its use for direct addition to
food is limited to a role as a flavoring ingredient in a few foods at a maximum level below 10 ppm.
Uses
Different sources of media describe the Uses of 108-95-2 differently. You can refer to the following data:
1. Phenol is an important organic chemical raw material, widely used in the production of phenolic resin and bisphenol A, in which bisphenol A is important raw material for polycarbonate, epoxy resin, polysulfone resin and other plastics. In some cases the phenol is used to produce iso-octylphenol, isononylphenol, or isododecylphenol through addition reaction with long-chain olefins such as diisobutylene, tripropylene, tetra-polypropylene and the like, which are used in production of nonionic surfactants. In addition, it can also be used as an important raw material for caprolactam, adipic acid, dyes, medicines, pesticides and plastic additives and rubber auxiliaries.
2. The predominant use of phenol today is for phenolic resins.it is a powerful bactericide,phenol can be found in numerous consumer products includingmouthwashes,antiseptic ointments,throat lozenges,air fresheners,eardrops,and lipbalms.Phenol continues to be a primary chemical used to make thermoset resins.These resinsare made by combining phenol with aldehydes such as formaldehyde.More than 4 billionpounds of phenolic resins are used annually in the United States.Phenolic resins findtheir widest use in the construction industry.They are used as binding agents and fillers inwood products such as plywood,particleboard,furniture, and paneling.Phenolic resins areimpregnated into paper,which,after hardening,produces sheets that can be glued togetherto form laminates for use in wall paneling and countertops.Decking in boats and docksare made from phenolic resin composites.Phenolic resins are used as sealing agents andfor insulation. Because phenolic resins have high heat resistance and are good insulators,they are used in cookware handles.Because they are also good electrical insulators,they areused in electrical switches,wall plates, and for various other electrical applications.In theautomotive industry,phenolic resins are used for parts such as drive pulleys,water pumphousings, brakes,and body parts.In addition to the construction industry,phenol has many other applications.It isused in pharmaceuticals,in herbicides and pesticides,and as a germicide in paints.It can beused to produce caprolactam,which is the monomer used in the production of nylon 6.Another important industrial compound produced from phenol is bisphenol A,which ismade from phenol and acetone.Bisphenol A is used in the manufacture of polycarbonateresins.Polycarbonate resins are manufactured into structural parts used in the manufactureof various products such as automobile parts,electrical products,and consumer appliances.Items such as compact discs, reading glasses,sunglasses,and water bottles are made frompolycarbonates.
3. Phenol is used in the manufacture of variousphenolic resins; as an intermediate in the production of many dyes and pharmaceuticals;as a disinfectant for toilets, floors, and drains;as a topical antiseptic; and as a reagentin chemical analysis. It has been detectedin cigarette smoke and automobile exhaust.Smoke emitted from a burning mosquito coil(a mosquito repellent) has been found to con-tain submicron particles coated with phenoland other substances; a lengthy exposure canbe hazardous to health (Liu et al. 1987).
4. phenol is frequently used for medical chemical face peels. It may trap free radicals and can act as a preservative. Phenol, however, is an extremely caustic chemical with a toxicity potential. It is considered undesirable for use in cosmetics. even at low concentrations, it frequently causes skin irritation, swelling, and rashes.
Production
Coal tar was once the main source of phenol, and was extracted from sodium hydroxide solution. In earlier time, people use sulfonation method to produce phenol: react sodium benzene sulfonate with sodium hydroxide to generate the sodium salt of phenol, and then treat it with acid to obtain phenol. In recent years, hydrolyzing chlorobenzene or oxidizing cumene has become the major production method. The by-product acetone in latter method is also an important industrial raw material, so oxidizing cumene is more economic industrially thus widely applied.
Cumene method:
This method generates cumene from propylene and benzene in the presence of aluminum trichloride. It oxidizes to cumene hydroperoxide and then decomposes with cation exchange resin to give phenol and acetone. For each ton of phenol produced, 0.62 tons of acetone can be produced.
Sulfonation method:
se sulfuric acid to sulfonate benzene to generate benzene sulfonic acid, neutralize it with sodium sulfite, and then undergo acidification and vacuum distillation in caustic soda solution.
Hydrogen benzene hydrolysis method: hydrogen benzene is hydrolyzed in caustic soda solution with high temperature and high pressure to generate phenol sodium, which is then neutralized to give phenol.
Toxicity
Phenol is highly corrosive and toxic. It mainly affects the central nervous system. The oral lethal dose for adults is 1 g. It can be irritating, numbing or necrotizing to the skin. It is toxic to skin contact, swallowing or inhalation of phenol. Misuse of a small amount of phenol can cause nausea, vomiting, shock, coma and even death in case of respiratory failure. Very few amounts are used as a preservative, so that adverse reactions are rarely found.
Due to its high toxicity, it has been replaced by more effective and less toxic phenolic derivatives.
Description
Phenol is a stable chemical substance and appear as colourless/white crystals with a
characteristic, distinct aromatic/acrid odour. It is reactive and incompatible with strong
oxidising agents, strong bases, strong acids, alkalis, and calcium hypochlorite. Phenol is
flammable and may discolour in light.
Phenol is used in the manufacture or production of explosives, fertiliser, coke, illuminating
gas, lampblack, paints, paint removers, rubber, perfumes, asbestos goods, wood
preservatives, synthetic resins, textiles, drugs, and pharmaceutical preparations. It is also
extensively used as a disinfectant in the petroleum, leather, paper, soap, toy, tanning, dye,
and agricultural industries.
Physical properties
Phenol is a colorless or white crystalline solid that is slightly soluble in water. Phenol is the
simplest of the large group of organic chemicals known as phenols, which consist of compounds
where a carbon in the phenyl aromatic group (C6H5) is directly bonded to hydroxyl,
OH.
Occurrence
It is reported found in over 150 natural products including apricot, sour cherry, black currant, bilberry,
cranberry, other berries, grapes, guava fruit, peach, pineapple, asparagus, onion, cooked potato, tomato, cinnamon bark, cassia
leaf, ginger, pennyroyal oil, many cheeses, butter, milk, milk powder, boiled egg, fish and fish oil, cooked and cured meats, beer,
wheaten bread, crisp bread, cognac, rose wine, cocoa, coffee, tea, whiskies, roasted filbert, roasted peanut, soybean, pecans,
honey, avocado, Arctic bramble, passion fruit, beans, mushrooms, burley tobacco, cooked beef and chicken, fermented soy sauce,
trassi, roasted almonds, sesame seed, fenugreek, mango, tamarind, Brazil nut, rice, rhubarb, licorice, buckwheat, watercress, malt,
wort, dried bonito, loquat, myrtle berry, rosemary, Tahiti and Bourbon vanilla, endive, shrimp, crab, crayfish, clam, squid, truffle
and Chinese quince.
History
Phenol’s first prominent use was by Joseph Lister (1827–1912) as an antiseptic.
Throughout human history,infection often resulted in death,even when the wound could
be surgically treated.A broken bone piercing the skin, which today is a painful but not
life-threatening injury,historically resulted in infection and possible amputation or death.
Lister was inspired by Louis Pasteur’s (1822–1895) germ theory of disease,and he began
to use antiseptic methods during routine surgery during the 1860s.
Definition
Different sources of media describe the Definition of 108-95-2 differently. You can refer to the following data:
1. ChEBI: An organic hydroxy compound that consists of benzene bearing a single hydroxy substituent. The parent of the class of phenols.
2. 1. (carbolic acid,
hydroxybenzene, C6H5OH) A white crystalline
solid used to make a variety of other
organic compounds.
2. A type of organic compound in which at
least one hydroxyl group is bound directly
to one of the carbon atoms of an aromatic
ring. Phenols do not show the behavior
typical of alcohols. In particular they are
more acidic because of the electron-withdrawing
effect of the aromatic ring. The
preparation of phenol itself is by fusing the
sodium salt of the sulfonic acid with
sodium hydroxide:
C6H5SO2.ONa + 2NaOH → C6H5ONa
+ Na2SO3 + H2O
The phenol is then liberated by sulfuric
acid:
2C6H5ONa + H2SO4 → 2C6H5OH +
Na2SO4
Reactions of phenol include:
1. Replacement of the hydroxyl group with
a chlorine atom using phosphorus(V)
chloride.
2. Reaction with acyl halides to form esters
of carboxylic acids.
3. Reaction with haloalkanes under alkaline
conditions to give mixed alkyl–aryl
ethers.
In addition phenol can undergo further
substitution on the benzene ring. The hydroxyl
group directs other substituents
into the 2- and 4-positions.
Production Methods
Different sources of media describe the Production Methods of 108-95-2 differently. You can refer to the following data:
1. Historically, phenol was produced by the distillation of coal tar.
Today, phenol is prepared by one of several synthetic methods, such
as the fusion of sodium benzenesulfonate with sodium hydroxide
followed by acidification; the hydrolysis of chlorobenzene by dilute
sodium hydroxide at high temperature and pressure to give sodium
phenate, which on acidification liberates phenol (Dow process); or
the catalytic vapor-phase reaction of steam and chlorobenzene at
500°C (Raschig process).
2. Phenol was prepared before World War I through the distillation of coal tar. The firstsynthetic process involved the sulfonation of benzene followed by desulfonation with abase.The most common current method of phenol production is from the cumene hydroperoxiderearrangement process.In this process,benzene reacts with propylene to produce cumene.Cumene is oxidized to cumene hydroperoxide.When cumene hydroperoxide is treated withdilute sulfuric acid,it rearranges and splits into phenol and acetone. Because the reactants areinexpensive and the process is simple,the acidic oxidation of cumene is used to produce morethan 95% of the world’s supply of phenol.
Preparation
Phenol is formed in dry distillation of wood, peat and coal; coal tar is one of the commercial sources of phenol and its
homologues.
Indications
Phenol in dilute solution (0.5% to 2%) decreases itch by anesthetizing the cutaneous
nerve endings. Phenol should never be used on pregnant women or infants younger
than 6 months of age.
World Health Organization (WHO)
Phenol became widely used as an antiseptic following
demonstration of its germicidal activity in 1867. It is an intensely corrosive
substance and percutaneous absorption can produce serious systemic toxicity. It
has been withdrawn from pharmaceutical preparations by at least one national
regulatory authority. However, it is still used widely in concentrations of the order
of 1.4% in proprietary preparations for the relief of soreness of the mouth and
throat.
Aroma threshold values
Detection: 5.5 ppm. Aroma characteristics at 1.0%: medicinal, creosote, smoky, spicy, phenolic, leatherlike
with notes of fried meat and coffee.
Taste threshold values
Taste characteristics at 3 ppm: spicy, phenolic, tobacco, musty, woody, medicinal, smoky, tarlike and
slightly spicy clovelike.
Synthesis Reference(s)
Journal of the American Chemical Society, 107, p. 2153, 1985 DOI: 10.1021/ja00293a054Synthetic Communications, 19, p. 453, 1989 DOI: 10.1080/00397918908050686
General Description
A solid melting at 110°F. Colorless if pure, otherwise pink or red. Flash point 175°F. Density 9.9 lb / gal. Vapors are heavier than air Corrosive to the skin (turning skin white) but because of its anesthetic quality numbs rather than burn. Lethal amounts can be absorbed through the skin. Used to make plastics and adhesives.
Air & Water Reactions
Decomposes slowly in air. Mixtures of 9-10% phenol in air are explosive. Soluble in water
Reactivity Profile
PHENOL is a weak acid. Reacts exothermically with bases. Reacts with strong oxidizing agents. Emits acrid smoke and irritating fumes when heated to decomposition. Undergoes, in the presence of aluminum chloride, potentially explosive reactions with nitromethane, butadiene, formaldehyde, peroxodisulfuric acid, peroxosulfuric acid, and sodium nitrite . Reacts violently with sodium nitrate in the presence of trifluoroacetic acid [Bretherick, 5th ed., 1995, p. 770]. May corrode lead, aluminum and its alloys, certain plastics, and rubber. Phenol may explode in contact with peroxodisulfuric acid (Dns, J. Ber., 1910, 43, 1880; Z. Anorg. Chem., 1911, 73, 1911.) or peroxomonosulfuric acid. (Sidgwick, 1950, 939)
Health Hazard
Phenol and its vapors are corrosive to the eyes, skin, and respiratory tract. The corrosive effect on skin and mucous membranes is due to a protein-degenerating effect. Repeated or prolonged skin contact with phenol may cause dermatitis, and potentially second and third-degree burns. Inhalation of phenol vapor may cause lung edema. Phenol may adversely effect the central nervous system and heart. Long-term, or repeated exposure, to phenol may have harmful effects on the liver and kidneys.While there is no evidence that phenol causes cancer in humans it is readily absorbed through the skin; systemic poisoning can occur in addition to the local caustic burns. Resorptive poisoning by a large quantity of phenol can occur even with only a small area of skin, rapidly leading to paralysis of the central nervous system and a severe drop in body temperature. Phenol is also a reproductive toxin causing increased risk of abortion and low birth weight indicating retarded development in utero.Chemical burns from skin exposures can be decontaminated by washing with polyethylene glycol or isopropyl alcohol; flushing with copious amounts of water will help to remediate the burn. Removal of contaminated clothing is required, as well as immediate hospital treatment for large splashes.https://ehs.ucsc.edu/lab-safety-manual/specialty-chemicals/phenol.html
Fire Hazard
Flammable vapors when heated. Runoff from fire control water may give off poisonous gases and cause pollution. Mixtures of 9-10% phenol in air are explosive. Avoid aluminum chloride/nitrobenzene mixture, peroxodisulfuric acid, peroxomonosulfuric acid and strong oxidizing agents. Decomposes slowly on air contact. Avoid contact with strong oxidizing agents.
Flammability and Explosibility
Phenol is a combustible solid (NFPA rating = 2). When heated, phenol produces
flammable vapors that are explosive at concentrations of 3 to 10% in air. Carbon
dioxide or dry chemical extinguishers should be used to fight phenol fires.
Pharmaceutical Applications
Phenol is used mainly as an antimicrobial preservative in parenteral
pharmaceutical products. It has also been used in topical
pharmaceutical formulations and cosmetics;
Phenol is widely used as an antiseptic, disinfectant, and
therapeutic agent, although it should not be used to preserve
preparations that are to be freeze-dried.
Industrial uses
Phenol is the simplest member of a class oforganic compounds possessing a hydroxylgroup attached to a benzene ring or to a morecomplex aromatic ring system. Also known as carbolic acid or monohydroxybenzene,phenol is a colorless to whitecrystalline material of sweet odor, having thecomposition C6H5OH, obtained from the distillationof coal tar and as a by-product ofcoke ovens. Phenol has broad biocidal properties, anddilute aqueous solutions have long been usedas an antiseptic. At higher concentrations itcauses severe skin burns; it is a violent systemicpoison. It is a valuable chemical raw materialfor the production of plastics, dyes, pharmaceuticals,syntans, and other products.Phenol is one of the most versatile industrialorganic chemicals. It is the starting point formany diverse products used in the home andindustry. A partial list includes nylon, epoxyresins, surface active agents, synthetic detergents,plasticizers, antioxidants, lube oil additives,phenolic resins (with formaldehyde, furfural,and so on), cyclohexanol, adipic acid,polyurethanes, aspirin, dyes, wood preservatives,herbicides, drugs, fungicides, gasolineadditives, inhibitors, explosives, and pesticides.
Biochem/physiol Actions
Phenol?has the ability to denature protein, hence can lead to denervation. At lower concentration, it can serve as a local anaesthetic and can also act as a neurolytic agent in higher concentration. It is also linked with tissue damage at higher concentrations.
Safety
Phenol is highly corrosive and toxic, the main effects being on the
central nervous system. The lethal human oral dose is estimated to
be 1 g for an adult.
Phenol is absorbed from the gastrointestinal tract, skin, and
mucous membranes, and is metabolized to phenylglucuronide and
phenyl sulfate, which are excreted in the urine.
Although there are a number of reports describing the toxic
effects of phenol, these largely concern instances of accidental
poisoning or adverse reactions during its use as a therapeutic
agent.Adverse reactions associated with phenol used as a
preservative are less likely owing to the smaller quantities that are
used; however, it has been suggested that the body burden of phenol
should not exceed 50 mg in a 10-hour period.This amount could
be exceeded following administration of large volumes of phenolpreserved
medicines.
LD50 (mouse, IV): 0.11 g/kg
LD50 (mouse, oral): 0.3 g/kg
LD50 (rabbit, skin): 0.85 g/kg
LD50 (rat, skin): 0.67 g/kg
LD50 (rat, oral): 0.32 g/kg
LD50 (rat, SC): 0.46 g/kg
Potential Exposure
Phenol is used as a pharmaceutical, in the production of fertilizer; coke, illuminating gas; lampblack, paints, paint removers; rubber, asbestos goods; wood preservatives; synthetic resins; textiles, drugs, pharmaceutical preparations; perfumes, bakelite, and other plastics (phenolformaldehyde resins); polymer intermediates (caprolactam, bisphenol-A and adipic acid). Phenol also finds wide use as a disinfectant and veterinary drug.
Carcinogenicity
Phenol had been investigated for carcinogenicity in animals by the oral and dermal routes. IARC and IRIS determined that animal human evidence for carcinogenicity was inadequate.
Source
Detected in distilled water-soluble fractions of 87 octane unleaded gasoline (1.53 mg/L),
94 octane unleaded gasoline (0.19 mg/L), Gasohol (0.33 mg/L), No. 2 fuel oil (0.09 mg/L), jet fuel
A (0.09 mg/L), diesel fuel (0.07 mg/L), and military jet fuel JP-4 (0.22 mg/L) (Potter, 1996).
Phenol was also detected in 80% of 65 gasoline (unleaded regular and premium) samples (62 from
Switzerland, 3 from Boston, MA). At 25 °C, phenol concentrations ranged from 63 to 130,000
μg/L in gasoline and from 150 to 1,500 μg/L in water-soluble fractions. Average concentrations
were 26 mg/L in gasoline and 6.1 mg/L in water-soluble fractions (Schmidt et al., 2002).
Thomas and Delfino (1991) equilibrated contaminant-free groundwater collected from
Gainesville, FL with individual fractions of three individual petroleum products at 24–25 °C for
24 h. The aqueous phase was analyzed for organic compounds via U.S. EPA approved test method
625. Average phenol concentrations reported in water-soluble fractions of unleaded gasoline,
kerosene, and diesel fuel were 20, 8, and 19 μg/L, respectively.
A high-temperature coal tar contained phenol at an average concentration of 0.61 wt %
(McNeil, 1983).
Phenol occurs naturally in many plants including blueberries (10 to 60 ppb), marjoram (1,431–
8,204 ppm), sweetflag, safflower buds (40 ppb), mud plantain, capillary wormwood, asparagus shoots, tea leaves, petitgrain, cinnamon, cassia, licorice, witch hazel, Japanese privet, St. John’s
wort, European pennyroyal, tomatoes, white mulberries, tobacco leaves, benneseed, sesame seeds,
tamarind, white sandlewood, patchouli leaves, rue, slash pine, bayberries, Scotch pine, and
tarragon (Duke, 1992).
A liquid swine manure sample collected from a waste storage basin contained phenol at a
concentration of 22.0 mg/L (Zahn et al., 1997).
Schauer et al. (2001) measured organic compound emission rates for volatile organic
compounds, gas-phase semi-volatile organic compounds, and particle phase organic compounds
from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission
rates of phenol were 525 mg/kg of pine burned, 300 mg/kg of oak burned, and 434 mg/kg of
eucalyptus burned.
Releases toxic and noxious fumes when heated at temperatures greater than its boiling point.
Drinking water standard: No MCLGs or MCLs have been proposed, however, a DWEL of 20
mg/L was recommended (U.S. EPA, 2000).
Environmental fate
Biological. Under methanogenic conditions, inocula from a municipal sewage treatment plant
digester degraded phenol to carbon dioxide and methane (Young and Rivera, 1985).
Chloroperoxidase, a fungal enzyme isolated from Caldariomyces fumago, reacted with phenol
forming 2- and 4-chlorophenol, the latter in a 25% yield (Wannstedt et al., 1990). In activated
sludge, 41.4% mineralized to carbon dioxide after 5 d (Freitag et al., 1985). When phenol was
statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater
inoculum, significant biodegradation with rapid adaptation was observed. At concentrations of 5
and 10 mg/L, 96 and 97% biodegradation, respectively, were observed after 7 d (Tabak et al.,
1981). Phenol is rapidly degraded in aerobically incubated soil but is much slower under anaerobic
conditions (Baker and Mayfield, 1980).
Soil. Loehr and Matthews (1992) studied the degradation of phenol in different soils under
aerobic conditions. In a slightly basic sandy loam (3.25% organic matter) and in acidic clay soil
(<1.0% organic matter), the resultant degradation half-lives were 4.1 and 23 d, respectively.
Soil sorption distribution coefficients (Kd) were determined from centrifuge column tests using
kaolinite as the absorbent (Celorie et al., 1989). Values for Kd ranged from 0.010 to 0.054 L/g.
Surface Water. Vaishnav and Babeu (1987) reported a half-life of 11 d in river waters and 3 d in
harbor waters.
Groundwater. Nielsen et al. (1996) studied the degradation of phenol in a shallow, glaciofluvial,
unconfined sandy aquifer in Jutland, Denmark. As part of the in situ microcosm study, a cylinder
that was open at the bottom and screened at the top was installed through a cased borehole
approximately 5 m below grade. Five liters of water was aerated with atmospheric air to ensure
aerobic conditions were maintained. Groundwater was analyzed weekly for approximately 3
months to determine phenol concentrations with time. The experimentally determined first-order
biodegradation rate constant and corresponding half-life were 0.5/d and 33.4 h, respectively.
Vaishnav and Babeu (1987) reported a biodegradation rate constant of 0.035/d and a half-life of 20
d in groundwater.
Photolytic. Absorbs UV light at a maximum wavelength of 269 nm (Dohnal and Fenclová,
1995). In an aqueous, oxygenated solution exposed to artificial light (λ = 234 nm), phenol was
photolyzed to hydroquinone, catechol, 2,2 -, 2,4 - and 4,4 -dihydroxybiphenyl (Callahan et al.,
1979). When an aqueous solution containing potassium nitrate (10 mM) and phenol (1 mM) was
irradiated with UV light (λ = 290–350 nm) up to a conversion of 10%, the following products
formed: hydroxyhydroquinone, hydroquinone, resorcinol, hydroxybenzoquinone, benzoquinone,
catechol, nitrosophenol, 4-nitrocatechol, nitrohydroquinone, 2- and 4-nitrophenol. Catechnol and
hydroquinone were the major and minor products, respectively (Niessen et al., 1988). Titanium
dioxide suspended in an aqueous solution and irradiated with UV light (λ = 365 nm) converted
phenol to carbon dioxide at a significant rate (Matthews, 1986).
Chemical/Physical. In an environmental chamber, nitrogen trioxide (10,000 ppb) reacted
quickly with phenol (concentration 200 ppb to 1.4 ppm) to form phenoxy radicals and nitric acid
(Carter et al., 1981). The phenoxy radicals may react with oxygen and nitrogen dioxide to form
quinones and nitrohydroxy derivatives, respectively (Nielsen et al., 1983).
storage
When exposed to air and light, phenol turns a red or brown color,
the color being influenced by the presence of metallic impurities.
Oxidizing agents also hasten the color change. Aqueous solutions of
phenol are stable. Oily solutions for injection may be sterilized in
hermetically sealed containers by dry heat. The bulk material
should be stored in a well-closed, light-resistant container at a
temperature not exceeding 15°C.
Shipping
UN1671 Phenol, solid, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2312 Molten phenol, Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN2821 Phenol solutions, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.
Purification Methods
Steam is passed through a boiling solution containing 1mole of phenol and 1.5-2.0moles of NaOH in 5L of H2O until all non-acidic material has distilled. The residue is cooled, acidified with 20% (v/v) H2SO4, and the phenol is separated, dried with CaSO4 and fractionally distilled under reduced pressure. It is then fractionally crystallised several times from its melt [Andon et al. J Chem Soc 5246 1960]. Purification via the benzoate has been used by Berliner, Berliner and Nelidow [J Am Chem Soc 76 507 1954]. The benzoate,(m 70o, b 314o/760mm), is crystallised from 95% EtOH, then hydrolysed to the free phenol by refluxing with two equivalents of KOH in aqueous EtOH until the solution becomes homogeneous. It is acidified with HCl and extracted with diethyl ether. The ether layer is freed from benzoic acid by thorough extraction with aqueous NaHCO3, and, after drying and removing the ether, the phenol is distilled. Phenol has also been crystallised from a 75% w/w solution in water by cooling to 11o and seeding with a crystal of the hydrate. The crystals are centrifuged off, rinsed with cold water (0-2o), saturated with phenol, and dried. It can be crystallised from pet ether [Berasconi & Paschalis J Am Chem Soc 108 2969 1986]. Draper and Pollard [Science 109 448 1949] added 12% water, 0.1% aluminium (can also use zinc) and 0.05% NaHCO3 to phenol, and distilled it at atmospheric pressure until the azeotrope was removed, The phenol was then distilled at 25mm. Phenol has also been dried by distillation from the *benzene solution to remove the water/*benzene azeotrope and the excess *benzene, followed by distillation of the phenol at reduced pressure under nitrogen. Processes such as this are probably adequate for analytical grade phenol which has as its main impurity water. Phenol has also been crystallised from pet ether/*benzene or pet ether (b 40-60o). The purified material is stored in a vacuum desiccator over P2O5 or CaSO4. [Beilstein 6 IV 531.]
Incompatibilities
Phenol, available in solid or liquid form, is colorless to light pink and has a sweet aromatic odor. It is stable under normal conditions of storage and use. The liquid and vapor are combustible. Phenol is incompatible with strong oxidizing agents, calcium hypochlorite, halogens, halogenated compounds, aluminum chloride, and nitrobenzene. Hot phenol can attack aluminum, lead, magnesium and zinc. It can react exothermally with peroxymonosulfuric acid, sodium nitrate, 1,3-butadiene and boron trifluoride diethyl ether. When phenol is heated to decomposition (ca. 715 °C), decomposition products include carbon monoxide and carbon dioxide.https://www.cdc.gov/niosh/npg/npgd0493.htmlhttp://www51.honeywell.com/sm/common/documents/Public_Risk_Summary_-_GPS0075_Phenol_Dec_2012.pdf
Waste Disposal
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration.
Precautions
Acute poisoning of phenol by ingestion, inhalation or skin contact may lead to death.
Phenol is readily absorbed through the skin. It is highly toxic by inhalation. It is corrosive
and causes burns and severe irritation effects. During use and handling of phenol, occupational
workers should be very careful. Workers should use protective clothing, rubber
boots, and goggles to protect the eyes from vapors and spillage.
Regulatory Status
Included in the FDA Inactive Ingredients Database (injections).
Included in medicines licensed in the UK. Included in the Canadian
List of Acceptable Non-medicinal Ingredients.
Check Digit Verification of cas no
The CAS Registry Mumber 108-95-2 includes 6 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 3 digits, 1,0 and 8 respectively; the second part has 2 digits, 9 and 5 respectively.
Calculate Digit Verification of CAS Registry Number 108-95:
(5*1)+(4*0)+(3*8)+(2*9)+(1*5)=52
52 % 10 = 2
So 108-95-2 is a valid CAS Registry Number.
InChI:InChI=1/C6H6O/c7-6-4-2-1-3-5-6/h1-5,7H
108-95-2Relevant articles and documents
Chlorine-nickel interactions in gas phase catalytic hydrodechlorination: Catalyst deactivation and the nature of reactive hydrogen
Shin, Eun-Jae,Spiller, Andreas,Tavoularis, George,Keane, Mark A.
, p. 3173 - 3181 (1999)
The gas phase hydrodechlorination of chlorobenzene and 3-chlorophenol (where 473 K ≤ T ≤ 573 K) has been studied using a 1.5% w/w Ni/SiO2 catalyst which was also employed to promote the hydrogenation of benzene, cyclohexene and phenol. In the former two instances the catalyst was 100% selective in removing the chlorine substituent, leaving the aromatic ring intact. While the dechlorination of chlorobenzene readily attained steady state with no appreciable deactivation, the turnover of 3-chlorophenol to phenol was characterised by both a short and a long term loss of activity. Chlorine coverage of the catalyst surface under reaction conditions was probed indirectly by monitoring, via pH changes in an aqueous NaOH trap, HCI desorption after completion of the catalytic step. Contacting the catalyst with the chlorinated reactants was found to severely limit and, depending on the degree of contact, completely inhibit aromatic ring reduction although a high level of hydrodechlorination activity was maintained. Hydrogen temperature programmed desorption (TPD) reveals the existence of three forms of surface hydrogen which are tentatively assigned as: (i) hydrogen bound to the surface nickel; (ii) hydrogen at the nickel/silica interface; (iii) spillover hydrogen on the silica support. The effect of chlorine-nickel interactions on the resultant TPD profiles is presented and discussed. The (assigned) spillover hydrogen appears to be hydrogenolytic in nature and is responsible for promoting hydrodechlorination while the hydrogen that is taken to be chemisorbed on, and remains associated with, the surface nickel metal participates in aromatic hydrogenation. Hydrodechlorination proceeds via an electrophilic mechanism, possibly involving spillover hydronium ions. The experimental catalytic data are adequately represented by a kinetic model involving non-competitive adsorption between hydrogen and the chloroaromatic, where incoming chloroaromatic must displace the HCI that remains on the surface after the dechlorination step. Kinetic parameters extracted from the model reveal that chlorophenol has a higher affinity than chlorobenzene for the catalyst surface but the stronger interaction leads to a greater displacement of electron density at the metal site and this ultimately leads to catalyst deactivation.
Gordon,Miller,Day
, (1949)
Baxendale,Magee
, p. 160 (1953)
-
Kupferberg
, p. 442 (1877)
-
Debromination of 2,4,6-tribromophenol coupled with biodegradation
Weidlich, Tomas,Prokes, Lubomir,Pospisilova, Dagmar
, p. 979 - 987 (2013)
The application effect of aluminium and their alloys and mixtures with nickel was studied for the complete hydrodebromination of 2,4,6-tribromophenol (TBP) to phenol in aqueous NaOH solution at room temperature. It was found that the Raney Al-Ni alloy can
Photocatalytic degradation of 2,4-dichlorophenol with V2O5-TiO2 catalysts: Effect of catalyst support and surfactant additives
Sinirtas, Eda,Isleyen, Meltem,Soylu, Gulin Selda Pozan
, p. 607 - 615 (2016)
Binary oxide catalysts with various weight percentage V2O5 loadings were prepared by solid-state dispersion and the nanocomposites were modified with surfactants. The catalysts were analyzed using X-ray diffraction, diffuse-reflectance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, and N2 adsorption-desorption. The photocatalytic activities of the catalysts were evaluated in the degradation of 2,4-dichlorophenol under ultraviolet irradiation. The photocatalytic activity of 50 wt% V2O5-TiO2 (50V2O5-TiO2) was higher than those of pure V2O5, TiO2, and P25. Interactions between V2O5 and TiO2 affected the photocatalytic efficiencies of the binary oxide catalysts. Cetyltrimethylammonium bromide (CTAB) and hexadecyltrimethylammonium bromide (HTAB) significantly enhanced the efficiency of the 50V2O5-TiO2 catalyst. The highest percentage of 2,4-dichlorophenol degradation (100%) and highest reaction rate (2.22 mg/(L·min)) were obtained in 30 min with the (50V2O5-TiO2)-CTAB catalyst. It is concluded that the addition of a surfactant to the binary oxide significantly enhanced the photocatalytic activity by modifying the optical and electronic properties of V2O5 and TiO2.
Spectroscopic and QM/MM investigations of Chloroperoxidase catalyzed degradation of orange G
Zhang, Rui,He, Qinghao,Huang, Yi,Wang, Xiaotang
, p. 1 - 9 (2016)
Chloroperoxidase (CPO), a heme-thiolate protein, from Caldariomyces fumago catalyzes a plethora of reactions including halogenation, dismutation, epoxidation, and oxidation. Although all CPO-catalyzed reactions go through a common intermediate, compound I, different mechanisms are followed in subsequent transformations. To understand the mechanism of CPO-catalyzed halide-dependent degradation of orange G, the role of halide and pH was systematically investigated. It is revealed that formation and protonation of compound X, a long-sought after hypochlorite heme adduct intermediate existed during CPO-catalyzed halide-dependent reactions, significantly lowers the reaction barrier and increases the efficiency of CPO-catalyzed orange G degradation. The extremely acidic optimal reaction pH suggests the protonation of a residue, presumably, Glu 183 in CPO catalysis. Halide dependent studies showed that Kcat is higher in the presence of Br- than in the presence of Cl-. The degradation products of orange G indicate the cleavage at a single position of orange G, demonstrating a high regioselectivity of CPO-catalyzed degradation. Based on our kinetic, NMR and QM/MM studies, the mechanism of CPO-catalyzed orange G degradation was proposed.
Solvent-Induced Single Crystal-Single Crystal Transformation of an Interpenetrated Three-Dimensional Copper Triazole Catalytic Framework
Wang, Ying,Meng, Shan-Shan,Lin, Peng-Xiang,Xiao, Yi-Wei,Ma, Qing-Qing,Xie, Qiong,Chen, Yuan-Yuan,Zhao, Xiao-Jun,Chen, Jun
, p. 4069 - 4071 (2016)
The 2-fold interpenetrated 3D framework 1 can be solvent-induced to noninterpenetrated framework 1′ in a reversible single crystal-single crystal transformation fashion. In addition, 1′ represents the first catalyst based on triazole to catalyze the aerobic homocoupling of various substituted arylboronic acids.
Photo-Fries rearrangement of 1-pyrenyl esters
Maeda, Hajime,Akai, Tomomi,Segi, Masahito
, p. 4377 - 4380 (2017)
Photo-Fries rearrangement reactions of 1-pyrenyl esters were investigated. Photoreaction of 1-pyrenyl benzoate in benzene generates 1-hydroxy-2-pyrenyl phenyl ketone along with 1-pyrenol. The exceptionally down field 1H NMR chemical shift of OH proton in the photoproduct indicates the existence of intramolecular hydrogen bonding. Photorearrangements of analogs that have electron-withdrawing or electron-releasing group on the phenyl ring, and related heteroaromatic carboxylates also take place to form the corresponding ketones. However, photoreactions of 1-pyrenyl aliphatic carboxylate esters do not occur. The results of spectroscopic and theoretical studies suggest the mechanistic pathway for this process is initiated by homolytic C–O bond cleavage in an aroyl group localized 1(π → π?) excited state of the 1-pyrenyl esters. The radical pair generated in this fashion then undergoes in-solvent-cage coupling to yield the 1-hydroxy-2-pyrenyl aryl ketone selectively.
Selective enzymatic hydrolysis of phenolic acetates
Basavaiah,Raju
, p. 467 - 473 (1994)
Phenolic acetates are selectively hydrolyzed in the presence of alkyl acetates, methyl esters and cinnamates with pig liver acetone powder (PLAP).
Vanadium oxyacetylacetonate grafted on UiO-66-NH2 for hydroxylation of benzene to phenol with molecular oxygen
Wang, Weitao,Li, Na,Tang, Hao,Ma, Yangmin,Yang, Xiufang
, p. 113 - 120 (2018)
V/UiO-66-NH2 was prepared by the vanadium oxyacetylacetonate grafted on UiO-66-NH2. The catalytic performance of V/UiO-66-NH2 was investigated for the hydroxylation of benzene to phenol using O2. It can give the
Bronsted acid-functionalized choline chloride-butane sultone for the catalytic decomposition of cumene hydroperoxide to phenol
Padma priya,Rajarajeswari
, (2018)
Abstract: Choline chloride and 1,4-butane sultone were combined to obtain a sulphonic acid-functionalized ionic liquid. The structural properties of the ionic liquid were evaluated with AT-IR, NMR, mass and elemental analysis. The Bronsted acidity of the
Long-Lived Photoexcited State of a Mn(IV)-Oxo Complex Binding Scandium Ions That is Capable of Hydroxylating Benzene
Sharma, Namita,Jung, Jieun,Ohkubo, Kei,Lee, Yong-Min,El-Khouly, Mohamed E.,Nam, Wonwoo,Fukuzumi, Shunichi
, p. 8405 - 8409 (2018)
Photoexcitation of a MnIV-oxo complex binding scandium ions ([(Bn-TPEN)MnIV(O)]2+-(Sc(OTf)3)2) in a solvent mixture of trifluoroethanol and acetonitrile (v/v = 1:1) resulted in formation of the long-l
Trapping hydrogen sulfide (H2S) with diselenides: The application in the design of fluorescent probes
Peng, Bo,Zhang, Caihong,Marutani, Eizo,Pacheco, Armando,Chen, Wei,Ichinose, Fumito,Xian, Ming
, p. 1541 - 1544 (2015)
Here we report a unique reaction between phenyl diselenide-ester substrates and H2S to form 1,2-benzothiaselenol-3-one. This reaction proceeded rapidly under mild conditions. Thiols could also react with the diselenide substrates. However, the resulted S-Se intermediate retained high reactivity toward H2S and eventually led to the same cyclized product 1,2-benzothiaselenol-3-one. Based on this reaction two fluorescent probes were developed and showed high selectivity and sensitivity for H2S. The presence of thiols was found not to interfere with the detection process.
Reductive dechlorination of 2,4-dichlorophenol by Pd/Fe nanoparticles prepared in the presence of ultrasonic irradiation
Zhao, Deming,Li, Min,Zhang, Dexing,Baig, Shams Ali,Xu, Xinhua
, p. 864 - 871 (2013)
Palladium/Iron (Pd/Fe) nanoparticles were prepared by using ultrasound strengthened liquid phase reductive method to enhance dispersion and avoid agglomeration. The dechlorination of 2,4-dichlorophenol (2,4-DCP) by Pd/Fe nanoparticles was investigated to understand its feasibility for an in situ remediation of contaminated groundwater. Results showed that 2,4-DCP was first adsorbed by Pd/Fe nanoparticles, then quickly reduced to o-chlorophenol (o-CP), p-chlorophenol (p-CP), and finally to phenol (P). The induction of ultrasound during the preparation of Pd/Fe nanoparticles further enhanced the removal efficiency of 2,4-DCP, as a result, the phenol production rates increased from 65% (in the absence of ultrasonic irradiation) to 91% (in the presence of ultrasonic irradiation) within 2 h. Our data suggested that the dechlorination rate was dependent on various factors including Pd loading percentage over Fe0, Pd/Fe nanoparticles availability, temperature, mechanical stirring speed, and initial pH values. Up to 99.2% of 2,4-DCP was removed after 300 min reaction with these conditions: Pd loading percentage over Fe 0 0.3 wt.%, initial 2,4-DCP concentration 20 mg L-1, Pd/Fe dosage 3 g L-1, initial pH value 3.0, and reaction temperature 25 °C. The degradation of 2,4-DCP followed pseudo-first-order kinetics reaction and the apparent pseudo-first-order kinetics constant was 0.0468 min -1.
Efficient visible-light-induced photocatalytic activity on gold-nanoparticle-supported layered titanate
Ide, Yusuke,Matsuoka, Mizuki,Ogawa, Makoto
, p. 16762 - 16764 (2010)
The visible-light-induced photocatalytic conversion of aqueous benzene to phenol on Au-nanoparticle-supported layered titanate was accelerated when the reaction was conducted in the presence of aqueous phenol.
Preparation of salicylic nitrile through direct catalytic dehydration of salicylamide with immobilized phosphoric acid as catalyst
Yao, Shu-Feng,Cai, Zhao-Sheng,Huang, Xu-Juan,Song, Lan-Xuan
, p. 1082 - 1086 (2020)
Salicylic nitrile was prepared through direct catalytic dehydration of salicylamide under high temperature using immobilized phosphoric acid as catalyst. The catalytic performances of different catalysts were evaluated according to the analytic results of
Cu(II) catalyzed reaction between phenyl hydrazine and toluidine blue - dual role of acid
Jonnalagadda,Nattar
, p. 271 - 276 (1999)
The detailed kinetics of Cu(II) catalyzed reduction of toluidine blue (TB+) by phenyl hydrazine (Pz) in aqueous solution is studied. Toluidine white (TBH) and the diazonium ions are the main products of the reaction. The diazonium ion further decomposes to phenol (PhOH) and nitrogen. At low concentrations of acid, H+ ion autocatalyzes the uncatalyzed reaction and hampers the Cu(II) catalyzed reaction. At high concentrations, H+ hinders both the uncatalyzed and Cu(II) catalyzed reactions. Cu(II) catalyzed had stoichiometry similar to the uncatalyzed reaction, Pz+2 TB++H2O = PhOH+2 TBH+2 H++N2. Cu(II) catalyzed reaction occurs possibly through ternary complex formation between the unprotonated toluidine blue and phenyl hydrazine and catalyst. The rate coefficient for the Cu(II) catalyzed reaction is 2.1×104 M-2 s-1. A detailed 13-step mechanistic scheme for the Cu(II) catalyzed reaction is proposed, which is supported by simulations.
UV-controlled shape memory hydrogels triggered by photoacid generator
Feng, Wei,Zhou, Wanfu,Zhang, Shidong,Fan, Yujiao,Yasin, Akram,Yang, Haiyang
, p. 81784 - 81789 (2015)
Light-induced shape memory polymers represent a class of stimuli-responsive materials that can recover their permanent shapes from temporarily trapped ones upon exposure to light illumination. Although much effort has been devoted to developing various light-responsive shape memory polymers, fabrication of such a light-responsive shape memory hydrogel still remains a challenge compared to neat polymers in their dry state. Herein, we developed a facile and general strategy to endow conventional hydrogel systems with ultraviolet (UV)-controlled shape memory performance simply using a photoacid generator (PAG) as a trigger. The process involves shape fixity through coordination interaction between imidazole groups and metal ions, and shape recovery by switching off the complexation via PAG photolysis reaction which leads to the protonation of imidazole groups. Furthermore, this convenient strategy is proved to be applicable to other pre-existing hydrogels such as a boronate ester cross-linked melamine-poly(vinyl alcohol) (PVA) hydrogel. We believe this method could provide a new opportunity with regard to the design and practical application of light-controlled shape memory hydrogels.
Catalytic dechlorination of chlorophenols in water by palladium/iron
Liu, Yihui,Yang, Fenglin,Yue, Po Lock,Chen, Guohua
, p. 1887 - 1890 (2001)
Three isomer chlorophenols, o-, m-, p-chlorophenol, were dechlorinated by palladium/iron powder in water through catalytic reduction. The dechlorinated reaction is believed to take place on the surface site of the catalyst in a pseudo-first-order reaction. The reduction product for all the three isomers is phenol. The dechlorination rate increases with increase of bulk loading of palladium due to the increase of both the surface loading of palladium and the total surface area. The molecular structure also has an effect on the dechlorination rate. For conditions with 0.048% Pd/Fe, the rate constants are 0.0215, 0.0155 and 0.0112min-1 for o-, m-, p-chlorophenol, respectively. Almost complete dechlorination is achieved within 5h. Copyright
Photochemical Reactions in the Benzophenone/tert-Butyl Alcohol/Oxygen System. Some Unexpected Results
Gramain, Jean-Claude,Remuson, Roland
, p. 1120 - 1122 (1985)
-
Stable N-functionalised 'pincer' bis carbene ligands and their ruthenium complexes; synthesis and catalytic studies
Danopoulos, Andreas A.,Winston, Scott,Motherwell, William B.
, p. 1376 - 1377 (2002)
Deprotonation of 2,6-bis(arylimidazolium)pyridine dibromide with KN(SiMe3)2 gave thermally stable 2,6-bis(arylimidazol-2-ylidene)pyridine, which was further used to prepare ruthenium 'pincer' complexes; the latter show catalytic activity in transfer hydrogenation of carbonyl compounds.
Ionic-liquid-functionalized polyoxometalates for heterogeneously catalyzing the aerobic oxidation of benzene to phenol: Raising efficacy through specific design
Long, Zhouyang,Zhou, Yu,Ge, Weilin,Chen, Guojian,Xie, Jingyan,Wang, Qian,Wang, Jun
, p. 1590 - 1596 (2014)
By combining nitrile-tethered pyridinium-based ionic liquid dication with the polyoxometalate anion of Keggin H5PMo10V2O40 (PMoV2) through precipitation in aqueous solution, an organic-inorganic hybri
Hydroxylation of benzene to phenol by molecular oxygen over an organic-inorganic hybrid catalyst: Schiff base manganese complex attached to molybdovanadophosphoric heteropolyacid
Zhou, Changjiang,Wang, Jun,Leng, Yan,Ge, Hanqing
, p. 120 - 125 (2010)
The organic-inorganic hybrid catalyst L-Mn-PMoV was prepared simply by combining a schiff base Mn complex (L-Mn, L: N,N-disalicylidene-1, 6-hexanediamine) with the Keggin-structured molybdovanadophosphoric heteropolyacid (PMoV). The proposed composition and structure of the catalyst were evidenced by TG, elemental analysis, FT-IR, and UV-Vis characterizations. Its catalytic performance was evaluated in the direct hydroxylation of benzene to phenol by molecular oxygen with ascorbic acid as the reducing agent. Various reaction parameters were changed to attain the optimal conditions. The hybrid catalyst has a formula [{Mn(C20H22N2O 2)(Cl)}2(H4PMo11VO40)], with the two terminal oxygen atoms in the PMoV Keggin structure coordinately linked to the two Mn(III) ions in two L-Mn units, respectively. It exhibits a remarkably enhanced yield to phenol compared to the pure PMoV due to the synergy effect between the Schiff-base manganese complex and PMoV. Graphical Abstract: [Figure not available: see fulltext.]
Active species formed in a Fenton-like system in the medium of triethylammonium acetate ionic liquid for hydroxylation of benzene to phenol
Hu, Xiaoke,Zhu, Liangfang,Wang, Xueqin,Guo, Bin,Xu, Jiaquan,Li, Guiying,Hu, Changwei
, p. 41 - 49 (2011)
High-valent iron(IV)-oxo species was proved to be the main oxidizing species for hydroxylation of benzene to phenol by a Fenton-like reagent in triethylammonium acetate ionic liquid via UV-vis and ESI-MS characterization, while hydroxyl radical was excluded by detailed investigations. It was found that the formation of hydroxyl radical was prohibited by the reduction of redox potential of Fe(III)/Fe(II) couple in triethylammonium acetate medium, leading to a decreased over-oxidation of benzene than that in aqueous solution. The reaction mechanisms for hydroxylation of benzene, as well as for over-oxidation of phenol by iron(IV)-oxo species were proposed. The latter is partly prohibited by the hydrogen-bond interaction between as-produced phenol and acetate anion of the ionic liquid.
Steady-state kinetic analysis of human cholinesterases over wide concentration ranges of competing substrates
Mukhametgalieva, Aliya R.,Lushchekina, Sofya V.,Aglyamova, Aliya R.,Masson, Patrick
, (2021/10/22)
Substrate competition for human acetylcholinesterase (AChE) and human butyrylcholinesterase (BChE) was studies under steady-state conditions using wide range of substrate concentrations. Competing couples of substates were acetyl-(thio)esters. Phenyl acetate (PhA) was the reporter substrate and competitor were either acetylcholine (ACh) or acetylthiocholine (ATC). The common point between investigated substrates is that the acyl moiety is acetate, i.e. same deacylation rate constant for reporter and competitor substrate. Steady-state kinetics of cholinesterase-catalyzed hydrolysis of PhA in the presence of ACh or ATC revealed 3 phases of inhibition as concentration of competitor increased: a) competitive inhibition, b) partially mixed inhibition, c) partially uncompetitive inhibition for AChE and partially uncompetitive activation for BChE. This sequence reflects binding of competitor in the active centrer at low concentration and on the peripheral anionic site (PAS) at high concentration. In particular, it showed that binding of a competing ligand on PAS may affect the catalytic behavior of AChE and BChE in an opposite way, i.e. inhibition of AChE and activation of BChE, regardless the nature of the reporter substrate. For both enzymes, progress curves for hydrolysis of PhA at very low concentration (?Km) in the presence of increasing concentration of ATC showed that: a) the competing substrate and the reporter substrate are hydrolyzed at the same time, b) complete hydrolysis of PhA cannot be reached above 1 mM competing substrate. This likely results from accumulation of hydrolysis products (P) of competing substrate and/or accumulation of acetylated enzyme·P complex that inhibit hydrolysis of the reporter substrate.
A highly efficient transformation from cumene to cumyl hydroperoxide via catalytic aerobic oxidation at room temperature and investigations into solvent effects, reaction networks and mechanisms
Chen, Chong,Ji, Lijun,Lu, Qiuting,Shi, Guojun,Yuan, Enxian,Zhou, Hongyu
, (2021/12/04)
Cumyl hydroperoxide (CHP) is an important intermediate for the production of phenol/acetone, but suffers from severe reaction conditions and a low yield industrially. Here, an efficient transformation from cumene to CHP was developed. Different solvents were modulated for cumene oxidation catalyzed by NHPI/Co, and reaction network and mechanisms were investigated methodically. Hexafluoroisopropanol (HFIP) markedly promoted the transformation from cumene to CHP compared to other solvents at room temperature. A cumene conversion high up to 64.3% were observed with a selectivity to CHP of 71.7%. The solvent HFIP exhibited a significant promotion on cumene oxidation due to its contribution to the enhancement of the concentration of PINO radicals. Moreover, cumyl, cumyl oxyl and methyl radicals were captured by TEMPO and analyzed by HRMS, and the reaction paths and mechanisms from cumene to products were inferred. The preparation method discovered in this work may open an access to the production of CHP.
Imidazolium-urea low transition temperature mixtures for the UHP-promoted oxidation of boron compounds
Martos, Mario,Pastor, Isidro M.
, (2022/01/03)
Different carboxy-functionalized imidazolium salts have been considered as components of low transition temperature mixtures (LTTMs) in combination with urea. Among them, a novel LTTM based on 1-(methoxycarbonyl)methyl-3-methylimidazolium chloride and urea has been prepared and characterized by differential scanning calorimetry throughout its entire composition range. This LTTM has been employed for the oxidation of boron reagents using urea-hydrogen peroxide adduct (UHP) as the oxidizer, thus avoiding the use of aqueous H2O2, which is dangerous to handle. This metal-free protocol affords the corresponding alcohols in good to quantitative yields in up to 5 mmol scale without the need of further purification. The broad composition range of the LTTM allows for the reaction to be carried out up to three consecutive times with a single imidazolium salt loading offering remarkable sustainability with an E-factor of 7.9, which can be reduced to 3.2 by the threefold reuse of the system.