Names | |||
---|---|---|---|
IUPAC name Acetone [2] | |||
Preferred IUPAC name Propan-2-one [3] | |||
Systematic IUPAC name 2-Propanone | |||
Other names | |||
Identifiers | |||
3D model (JSmol) | |||
3DMet | |||
635680 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.000.602 | ||
EC Number |
| ||
1466 | |||
KEGG | |||
MeSH | Acetone | ||
PubChem CID | |||
RTECS number |
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UNII | |||
UN number | 1090 | ||
CompTox Dashboard (EPA) | |||
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Properties | |||
C3H6O | |||
Molar mass | 58.080 g·mol−1 | ||
Appearance | Colourless liquid | ||
Odor | Pungent, fruity [9] | ||
Density | 0.7845 g/cm3 (25 °C) [10] | ||
Melting point | −94.9 °C (−138.8 °F; 178.2 K) [10] | ||
Boiling point | 56.08 °C (132.94 °F; 329.23 K) [10] | ||
Miscible [10] | |||
Solubility | Miscible in benzene, diethyl ether, methanol, chloroform, ethanol [10] | ||
log P | −0.24 [11] | ||
Vapor pressure |
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Acidity (pKa) | |||
−33.8·10−6 cm3/mol [14] | |||
Thermal conductivity | 0.161 W/(m·K) (25 °C) [15] | ||
Refractive index (nD) | 1.3588 (20 °C) [10] | ||
Viscosity | 0.306 mPa·s (25 °C) [16] | ||
Structure | |||
Trigonal planar at C2 | |||
Dihedral at C2 | |||
2.88 D [17] | |||
Thermochemistry [18] | |||
Heat capacity (C) | 126.3 J/(mol·K) | ||
Std molar entropy (S⦵298) | 199.8 J/(mol·K) | ||
Std enthalpy of formation (ΔfH⦵298) | −248.4 kJ/mol | ||
Std enthalpy of combustion (ΔcH⦵298) | −1.79 MJ/mol | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | Highly flammable | ||
GHS labelling: | |||
Danger | |||
H225, H302, H319, H336, H373 | |||
P210, P235, P260, P305+P351+P338 | |||
NFPA 704 (fire diamond) | |||
Flash point | −20 °C (−4 °F; 253 K) [19] | ||
465 [19] °C (869 °F; 738 K) | |||
Explosive limits | 2.5–12.8% [19] | ||
Threshold limit value (TLV) | 250 ppm [20] (STEL), 500 ppm [20] (C) | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) |
| ||
LC50 (median concentration) | 20,702 ppm (rat, 8 h) [21] | ||
LCLo (lowest published) | 45,455 ppm (mouse, 1 h) [21] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible) | 1000 ppm (2400 mg/m3) [5] | ||
REL (Recommended) | TWA 250 ppm (590 mg/m3) [5] | ||
IDLH (Immediate danger) | 2500 ppm [5] | ||
Related compounds | |||
Related compounds | |||
Supplementary data page | |||
Acetone (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Acetone (2-propanone or dimethyl ketone) is an organic compound with the formula (CH3)2CO. [22] It is the simplest and smallest ketone (>C=O). It is a colorless, highly volatile, and flammable liquid with a characteristic pungent odour, very reminiscent of the smell of pear drops.
Acetone is miscible with water and serves as an important organic solvent in industry, home, and laboratory. About 6.7 million tonnes were produced worldwide in 2010, mainly for use as a solvent and for production of methyl methacrylate and bisphenol A, which are precursors to widely used plastics. [23] [24] It is a common building block in organic chemistry. It serves as a solvent in household products such as nail polish remover and paint thinner. It has volatile organic compound (VOC)-exempt status in the United States. [25]
Acetone is produced and disposed of in the human body through normal metabolic processes. It is normally present in blood and urine. People with diabetic ketoacidosis produce it in larger amounts. Ketogenic diets that increase ketone bodies (acetone, β-hydroxybutyric acid and acetoacetic acid) in the blood are used to counter epileptic attacks in children who suffer from refractory epilepsy. [26]
From the 17th century, and before modern developments in organic chemistry nomenclature, acetone was given many different names. They included "spirit of Saturn", which was given when it was thought to be a compound of lead and, later, "pyro-acetic spirit" and "pyro-acetic ester". [8]
Prior to the name "acetone" being coined by French chemists (see below), it was named "mesit" (from the Greek μεσίτης, meaning mediator) by Carl Reichenbach, who also claimed that methyl alcohol consisted of mesit and ethyl alcohol. [27] [8] Names derived from mesit include mesitylene and mesityl oxide which were first synthesised from acetone.
Unlike many compounds with the acet- prefix which have a 2-carbon chain, acetone has a 3-carbon chain. That has caused confusion because there cannot be a ketone with 2 carbons. The prefix refers to acetone's relation to vinegar (acetum in Latin, also the source of the words "acid" and "acetic"), rather than its chemical structure. [28]
Acetone was first produced by Andreas Libavius in 1606 by distillation of lead(II) acetate. [29] [30]
In 1832, French chemist Jean-Baptiste Dumas and German chemist Justus von Liebig determined the empirical formula for acetone. [31] [32] In 1833, French chemists Antoine Bussy and Michel Chevreul decided to name acetone by adding the suffix -one to the stem of the corresponding acid (viz, acetic acid) just as a similarly prepared product of what was then confused with margaric acid was named margarone. [33] [28] By 1852, English chemist Alexander William Williamson realized that acetone was methyl acetyl; [34] the following year, the French chemist Charles Frédéric Gerhardt concurred. [35] In 1865, the German chemist August Kekulé published the modern structural formula for acetone. [36] [37] Johann Josef Loschmidt had presented the structure of acetone in 1861, [38] but his privately published booklet received little attention. During World War I, Chaim Weizmann developed the process for industrial production of acetone (Weizmann Process). [39]
In 2010, the worldwide production capacity for acetone was estimated at 6.7 million tonnes per year. [40] With 1.56 million tonnes per year, the United States had the highest production capacity, [41] followed by Taiwan and China. The largest producer of acetone is INEOS Phenol, owning 17% of the world's capacity, with also significant capacity (7–8%) by Mitsui, Sunoco and Shell in 2010. [40] INEOS Phenol also owns the world's largest production site (420,000 tonnes/annum) in Beveren (Belgium). Spot price of acetone in summer 2011 was 1100–1250 USD/tonne in the United States. [42]
Acetone is produced directly or indirectly from propene. Approximately 83% of acetone is produced via the cumene process; [24] as a result, acetone production is tied to phenol production. In the cumene process, benzene is alkylated with propylene to produce cumene, which is oxidized by air to produce phenol and acetone:
Other processes involve the direct oxidation of propylene (Wacker-Hoechst process), or the hydration of propylene to give 2-propanol, which is oxidized (dehydrogenated) to acetone. [24]
Previously, acetone was produced by the dry distillation of acetates, for example calcium acetate in ketonic decarboxylation.
After that time, during World War I, acetone was produced using acetone-butanol-ethanol fermentation with Clostridium acetobutylicum bacteria, which was developed by Chaim Weizmann (later the first president of Israel) in order to help the British war effort, [24] [43] in the preparation of Cordite. [44] This acetone-butanol-ethanol fermentation was eventually abandoned when newer methods with better yields were found. [24]
Acetone is reluctant to form a hydrate: [45]
Like most ketones, acetone exhibits the keto–enol tautomerism in which the nominal keto structure (CH3)2C=O of acetone itself is in equilibrium with the enol isomer (CH3)C(OH)=(CH2) (prop-1-en-2-ol). In acetone vapor at ambient temperature, only 2.4×10−7% of the molecules are in the enol form. [46]
In the presence of suitable catalysts, two acetone molecules also combine to form the compound diacetone alcohol (CH3)C=O(CH2)C(OH)(CH3)2, which on dehydration gives mesityl oxide (CH3)C=O(CH)=C(CH3)2. This product can further combine with another acetone molecule, with loss of another molecule of water, yielding phorone and other compounds. [47]
Acetone is a weak Lewis base that forms adducts with soft acids like I2 and hard acids like phenol. Acetone also forms complexes with divalent metals. [48] [49]
Under ultraviolet light, acetone fluoresces.. [50]
The flame temperature of pure acetone is 1980 °C. [51]
At its melting point (−96 °C) is claimed to polymers to give a white elastic solid, soluble in acetone, stable for several hours at room temperature. To do so, a vapor of acetone is co-condensed with magnesium as a catalyst onto a very cold surface. [52] [53] [54]
Humans exhale several milligrams of acetone per day. It arises from decarboxylation of acetoacetate. [55] [56] Small amounts of acetone are produced in the body by the decarboxylation of ketone bodies. Certain dietary patterns, including prolonged fasting and high-fat low-carbohydrate dieting, can produce ketosis, in which acetone is formed in body tissue. Certain health conditions, such as alcoholism and diabetes, can produce ketoacidosis, uncontrollable ketosis that leads to a sharp, and potentially fatal, increase in the acidity of the blood. Since it is a byproduct of fermentation, acetone is a byproduct of the distillery industry. [55]
Acetone can then be metabolized either by CYP2E1 via methylglyoxal to D-lactate and pyruvate, and ultimately glucose/energy, or by a different pathway via propylene glycol to pyruvate, lactate, acetate (usable for energy) and propionaldehyde. [57] [58] [59]
About a third of the world's acetone is used as a solvent, and a quarter is consumed as acetone cyanohydrin, a precursor to methyl methacrylate. [23]
Acetone is used to synthesize methyl methacrylate. It begins with the initial conversion of acetone to acetone cyanohydrin via reaction with hydrogen cyanide (HCN):
In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified:
The third major use of acetone (about 20%) [23] is synthesizing bisphenol A. Bisphenol A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins. The synthesis involves the condensation of acetone with phenol:
Many millions of kilograms of acetone are consumed in the production of the solvents methyl isobutyl alcohol and methyl isobutyl ketone. These products arise via an initial aldol condensation to give diacetone alcohol. [24]
Condensation with acetylene gives 2-methylbut-3-yn-2-ol, precursor to synthetic terpenes and terpenoids. [60]
Acetone is a good solvent for many plastics and some synthetic fibers. It is used for thinning polyester resin, cleaning tools used with it, and dissolving two-part epoxies and superglue before they harden. It is used as one of the volatile components of some paints and varnishes. As a heavy-duty degreaser, it is useful in the preparation of metal prior to painting or soldering, and to remove rosin flux after soldering (to prevent adhesion of dirt and electrical leakage and perhaps corrosion or for cosmetic reasons), although it may attack some electronic components, such as polystyrene capacitors. [61]
Although itself flammable, acetone is used extensively as a solvent for the safe transportation and storage of acetylene, which cannot be safely pressurized as a pure compound. Vessels containing a porous material are first filled with acetone followed by acetylene, which dissolves into the acetone. One litre of acetone can dissolve around 250 litres of acetylene at a pressure of 10 bars (1.0 MPa). [62] [63]
Acetone is used as a solvent by the pharmaceutical industry and as a denaturant in denatured alcohol. [64] Acetone is also present as an excipient in some pharmaceutical drugs. [65] [ needs update ]
A variety of organic reactions employ acetone as a polar, aprotic solvent, e.g. the Jones oxidation.
Because acetone is cheap, volatile, and dissolves or decomposes with most laboratory chemicals, an acetone rinse is the standard technique to remove solid residues from laboratory glassware before a final wash. [66] Despite common desiccatory use, acetone dries only via bulk displacement and dilution. It forms no azeotropes with water (see azeotrope tables). [67] Acetone also removes certain stains from microscope slides. [68]
Acetone freezes well below −78 °C. An acetone/dry ice mixture cools many low-temperature reactions. [69] Make-up artists use acetone to remove skin adhesive from the netting of wigs and mustaches by immersing the item in an acetone bath, then removing the softened glue residue with a stiff brush. [70] Acetone is a main ingredient in many nail polish removers because it breaks down nail polish. [71] It is used for all types of nail polish removal, like gel nail polish, dip powder and acrylic nails. [72]
Proteins precipitate in acetone. [73] The chemical modifies peptides, both at α- or ε-amino groups, and in a poorly understood but rapid modification of certain glycine residues. [73]
In pathology, acetone helps find lymph nodes in fatty tissues (such as the mesentery) for tumor staging. [74] The liquid dissolves the fat and hardens the nodes, making them easier to find. [75]
Dermatologists use acetone with alcohol for acne treatments to chemically peel dry skin. Common agents used today for chemical peeling are salicylic acid, glycolic acid, azelaic acid, 30% salicylic acid in ethanol, and trichloroacetic acid (TCA). Prior to chemexfoliation, the skin is cleaned and excess fat removed in a process called defatting. Acetone, hexachlorophene, or a combination of these agents was used in this process. [76]
Acetone has been shown to have anticonvulsant effects in animal models of epilepsy, in the absence of toxicity, when administered in millimolar concentrations. [77] It has been hypothesized that the high-fat low-carbohydrate ketogenic diet used clinically to control drug-resistant epilepsy in children works by elevating acetone in the brain. [77] Because of their higher energy requirements, children have higher acetone production than most adults – and the younger the child, the higher the expected production. This indicates that children are not uniquely susceptible to acetone exposure. External exposures are small compared to the exposures associated with the ketogenic diet. [78]
Acetone's most hazardous property is its extreme flammability. In small amounts, acetone burns with a dull blue flame; in larger amounts, fuel evaporation causes incomplete combustion and a bright yellow flame. When hotter than acetone's flash point of −20 °C (−4 °F), air mixtures of 2.5‑12.8% acetone (by volume) may explode or cause a flash fire. Vapors can flow along surfaces to distant ignition sources and flash back.
Static discharge may also ignite acetone vapors, though acetone has a very high ignition initiation energy and accidental ignition is rare. [79] Acetone's auto-ignition temperature is the relatively high 465 °C (869 °F); [19] moreover, auto-ignition temperature depends upon experimental conditions, such as exposure time, and has been quoted as high as 535 °C. [80] Even pouring or spraying acetone over red-glowing coal will not ignite it, due to the high vapour concentration and the cooling effect of evaporation. [79]
Acetone should be stored away from strong oxidizers, such as concentrated nitric and sulfuric acid mixtures. [81] It may also explode when mixed with chloroform in the presence of a base. [82] [ clarification needed ] When oxidized without combustion, for example with hydrogen peroxide, acetone may form acetone peroxide, a highly unstable primary explosive. Acetone peroxide may be formed accidentally, e.g. when waste peroxide is poured into waste solvents. [83]
Acetone occurs naturally as part of certain metabolic processes in the human body, and has been studied extensively and is believed to exhibit only slight toxicity in normal use. There is no strong evidence of chronic health effects if basic precautions are followed. [84] It is generally recognized to have low acute and chronic toxicity if ingested and/or inhaled. [85] Acetone is not currently regarded as a carcinogen, a mutagen, or a concern for chronic neurotoxicity effects. [79]
Acetone can be found as an ingredient in a variety of consumer products ranging from cosmetics to processed and unprocessed foods. Acetone has been rated as a generally recognized as safe (GRAS) substance when present in drinks, baked foods, desserts, and preserves at concentrations ranging from 5 to 8 mg/L. [85]
Acetone is however an irritant, causing mild skin and moderate-to-severe eye irritation. At high vapor concentrations, it may depress the central nervous system like many other solvents. [86] Acute toxicity for mice by ingestion (LD50) is 3 g/kg, and by inhalation (LC50) is 44 g/m3 over 4 hours. [87]
Although acetone occurs naturally in the environment in plants, trees, volcanic gases, forest fires, and as a product of the breakdown of body fat, [88] the majority of the acetone released into the environment is of industrial origin.[ clarification needed ] Acetone evaporates rapidly, even from water and soil. Once in the atmosphere, it has a 22-day half-life and is degraded by UV light via photolysis (primarily into methane and ethane. [89] ) Consumption by microorganisms contributes to the dissipation of acetone in soil, animals, or waterways. [88]
In 1995, the United States Environmental Protection Agency (EPA) removed acetone from the list of volatile organic compounds. The companies requesting the removal argued that it would "contribute to the achievement of several important environmental goals and would support EPA's pollution prevention efforts", and that acetone could be used as a substitute for several compounds that are listed as hazardous air pollutants (HAP) under section 112 of the Clean Air Act. [90] In making its decision EPA conducted an extensive review of the available toxicity data on acetone, which was continued through the 2000s. It found that the evaluable "data are inadequate for an assessment of the human carcinogenic potential of acetone". [9]
On 30 July 2015, scientists reported that upon the first touchdown of the Philae lander on comet 67P 's surface, measurements by the COSAC and Ptolemy instruments revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl isocyanate, and propionaldehyde. [91] [92] [93]
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is often written as R−COOH or R−CO2H, sometimes as R−C(O)OH with R referring to an organyl group, or hydrogen, or other groups. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.
In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom bonded to two organyl groups. They have the general formula R−O−R′, where R and R′ represent the organyl groups. Ethers can again be classified into two varieties: if the organyl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.
In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.
In organic chemistry, a ketone is an organic compound with the structure R−C(=O)−R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group −C(=O)−. The simplest ketone is acetone, with the formula (CH3)2CO. Many ketones are of great importance in biology and industry. Examples include many sugars (ketoses), many steroids, and the solvent acetone.
Acetoacetic acid is the organic compound with the formula CH3COCH2COOH. It is the simplest beta-keto acid, and like other members of this class, it is unstable. The methyl and ethyl esters, which are quite stable, are produced on a large scale industrially as precursors to dyes. Acetoacetic acid is a weak acid.
Mesitylene or 1,3,5-trimethylbenzene is a derivative of benzene with three methyl substituents positioned symmetrically around the ring. The other two isomeric trimethylbenzenes are 1,2,4-trimethylbenzene (pseudocumene) and 1,2,3-trimethylbenzene (hemimellitene). All three compounds have the formula C6H3(CH3)3, which is commonly abbreviated C6H3Me3. Mesitylene is a colorless liquid with sweet aromatic odor. It is a component of coal tar, which is its traditional source. It is a precursor to diverse fine chemicals. The mesityl group (Mes) is a substituent with the formula C6H2Me3 and is found in various other compounds.
In organic chemistry, a dicarbonyl is a molecule containing two carbonyl groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls are in close enough proximity that their reactivity is changed, such as 1,2-, 1,3-, and 1,4-dicarbonyls. Their properties often differ from those of monocarbonyls, and so they are usually considered functional groups of their own. These compounds can have symmetrical or unsymmetrical substituents on each carbonyl, and may also be functionally symmetrical or unsymmetrical.
In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is R2C(OH)CN, where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst:
Acetamide (systematic name: ethanamide) is an organic compound with the formula CH3CONH2. It is an amide derived from ammonia and acetic acid. It finds some use as a plasticizer and as an industrial solvent. The related compound N,N-dimethylacetamide (DMA) is more widely used, but it is not prepared from acetamide. Acetamide can be considered an intermediate between acetone, which has two methyl (CH3) groups either side of the carbonyl (CO), and urea which has two amide (NH2) groups in those locations. Acetamide is also a naturally occurring mineral with the IMA symbol: Ace.
Acetylacetone is an organic compound with the chemical formula CH3−C(=O)−CH2−C(=O)−CH3. It is classified as a 1,3-diketone. It exists in equilibrium with a tautomer CH3−C(=O)−CH=C(−OH)−CH3. The mixture is a colorless liquid. These tautomers interconvert so rapidly under most conditions that they are treated as a single compound in most applications. Acetylacetone is a building block for the synthesis of many coordination complexes as well as heterocyclic compounds.
In organic chemistry, α-keto halogenation is a special type of halogenation. The reaction may be carried out under either acidic or basic conditions in an aqueous medium with the corresponding elemental halogen. In this way, chloride, bromide, and iodide functionality can be inserted selectively in the alpha position of a ketone.
Methyl methacrylate (MMA) is an organic compound with the formula CH2=C(CH3)COOCH3. This colorless liquid, the methyl ester of methacrylic acid (MAA), is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA).
Methyl isobutyl ketone (MIBK, 4-methylpentan-2-one) is an organic compound with the condensed chemical formula (CH3)2CHCH2C(O)CH3. This ketone is a colourless liquid that is used as a solvent for gums, resins, paints, varnishes, lacquers, and nitrocellulose.
Mesityl oxide is a α,β-unsaturated ketone with the formula CH3C(O)CH=C(CH3)2. This compound is a colorless, volatile liquid with a honey-like odor.
In organic chemistry, the Mukaiyama aldol addition is an organic reaction and a type of aldol reaction between a silyl enol ether and an aldehyde or formate. The reaction was discovered by Teruaki Mukaiyama in 1973. His choice of reactants allows for a crossed aldol reaction between an aldehyde and a ketone, or a different aldehyde without self-condensation of the aldehyde. For this reason the reaction is used extensively in organic synthesis.
The Favorskii reaction is an organic chemistry reaction between an alkyne and a carbonyl group, under basic conditions. The reaction was discovered in the early 1900s by the Russian chemist Alexei Yevgrafovich Favorskii.
In organic chemistry, vinylogy is the transmission of electronic effects through a conjugated organic bonding system. The concept was introduced in 1926 by Ludwig Claisen to explain the acidic properties of formylacetone and related ketoaldehydes. Formylacetone, technically CH3(C=O)CH2CH=O, only exists in the ionized form CH3(C−O−)=CH−CH=O or CH3(C=O)−CH=CH−O−. Its adjectival form, vinylogous, is used to describe functional groups in which the standard moieties of the group are separated by a carbon–carbon double bond.
In chemistry, the haloform reaction is a chemical reaction in which a haloform is produced by the exhaustive halogenation of an acetyl group, in the presence of a base. The reaction can be used to transform acetyl groups into carboxyl groups or to produce chloroform, bromoform, or iodoform. Note that fluoroform can't be prepared in this way.
Methoxyamine is the organic compound with the formula CH3ONH2. Also called O-methylhydroxylamine, it is a colourless volatile liquid that is soluble in polar organic solvent and in water. It is a derivative of hydroxylamine with the hydroxyl hydrogen replaced by a methyl group. Alternatively, it can be viewed as a derivative of methanol with the hydroxyl hydrogen replaced by an amino group. It is an isomer of N-methylhydroxylamine and aminomethanol. It decomposes in an exothermic reaction (-56 kJ/mol) to methane and azanone unless stored as a hydrochloride salt.
In organic chemistry, alkynylation is an addition reaction in which a terminal alkyne is added to a carbonyl group to form an α-alkynyl alcohol.
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