Names | |||
---|---|---|---|
Preferred IUPAC name Propan-2-ol [1] | |||
Other names 2-Propanol Isopropanol [2] Rubbing alcohol sec-Propyl alcohol 2-Hydroxypropane i-PrOH Dimethyl carbinol IPA | |||
Identifiers | |||
3D model (JSmol) | |||
635639 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.000.601 | ||
1464 | |||
KEGG | |||
PubChem CID | |||
RTECS number |
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UNII | |||
UN number | 1219 | ||
CompTox Dashboard (EPA) | |||
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Properties | |||
C3H8O | |||
Molar mass | 60.096 g/mol | ||
Appearance | Colorless liquid | ||
Odor | Pungent alcoholic odor | ||
Density | 0.786 g/cm3 (20 °C) | ||
Melting point | −89 °C (−128 °F; 184 K) | ||
Boiling point | 82.6 °C (180.7 °F; 355.8 K) | ||
Miscible with water | |||
Solubility | Miscible with benzene, chloroform, ethanol, diethyl ether, glycerol; soluble in acetone | ||
log P | −0.16 [3] | ||
Acidity (pKa) | 16.5 [4] | ||
−45.794·10−6 cm3/mol | |||
Refractive index (nD) | 1.3776 | ||
Viscosity | 2.86 cP at 15 °C 1.96 cP at 25 °C [5] 1.77 cP at 30 °C [5] | ||
1.66 D (gas) | |||
Pharmacology | |||
D08AX05 ( WHO ) | |||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards | Flammable, mildly toxic [6] | ||
GHS labelling: | |||
Danger | |||
H225, H302, H319, H336 | |||
P210, P261, P305+P351+P338 | |||
NFPA 704 (fire diamond) | |||
Flash point | Open cup:11.7 °C (53.1 °F; 284.8 K) Closed cup: 13 °C (55 °F) | ||
399 °C (750 °F; 672 K) | |||
Explosive limits | 2–12.7% | ||
Threshold limit value (TLV) | 980 mg/m3 (TWA), 1225 mg/m3 (STEL) | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose) | |||
LC50 (median concentration) |
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LCLo (lowest published) |
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NIOSH (US health exposure limits): | |||
PEL (Permissible) | TWA 400 ppm (980 mg/m3) [8] | ||
REL (Recommended) | TWA 400 ppm (980 mg/m3), ST 500 ppm (1225 mg/m3) [8] | ||
IDLH (Immediate danger) | 2000 ppm [8] | ||
Safety data sheet (SDS) | |||
Related compounds | |||
Related alcohols | 1-Propanol, ethanol, 2-butanol | ||
Supplementary data page | |||
Isopropyl alcohol (data page) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable, organic compound with a pungent alcoholic odor. [9]
Isopropyl alcohol, an organic polar molecule, is miscible in water, ethanol, and chloroform, demonstrating its ability to dissolve a wide range of substances including ethyl cellulose, polyvinyl butyral, oils, alkaloids, and natural resins. Notably, it is not miscible with salt solutions and can be separated by adding sodium chloride in a process known as salting out. It forms an azeotrope with water, resulting in a boiling point of 80.37 °C and is characterized by its slightly bitter taste. Isopropyl alcohol becomes viscous at lower temperatures, freezing at −89.5 °C, and has significant ultraviolet-visible absorbance at 205 nm. Chemically, it can be oxidized to acetone or undergo various reactions to form compounds like isopropoxides or aluminium isopropoxide. As an isopropyl group linked to a hydroxyl group (chemical formula (CH3)2CHOH) it is the simplest example of a secondary alcohol, where the alcohol carbon atom is attached to two other carbon atoms. It is a structural isomer of propan-1-ol and ethyl methyl ether. They all have the formula C3H8O.
It was first synthesized in 1853 by Alexander William Williamson and later produced for cordite preparation. It is produced through hydration of propene or hydrogenation of acetone, with modern processes achieving anhydrous alcohol through azeotropic distillation. Beyond its production, isopropyl alcohol serves in medical settings as a rubbing alcohol and hand sanitizer, and in industrial and household applications as a solvent. It is a common ingredient in products such as antiseptics, disinfectants and detergents. More than a million tonnes are produced worldwide annually. Despite its utility, isopropyl alcohol poses safety risks due to its flammability and potential for peroxide formation. Its ingestion or absorption leads to toxic effects including central nervous system depression and coma, primarily treated through supportive measures.
Isopropyl alcohol is miscible in water, ethanol, and chloroform, as it is an organic polar molecule. It dissolves ethyl cellulose, polyvinyl butyral, many oils, alkaloids, and natural resins. [10] Unlike ethanol or methanol, isopropyl alcohol is not miscible with salt solutions and can be separated from aqueous solutions by adding a salt such as sodium chloride. The process is colloquially called salting out , and causes concentrated isopropyl alcohol to separate into a distinct layer. [11]
Isopropyl alcohol forms an azeotrope with water, which gives a boiling point of 80.37 °C (176.67 °F) and a composition of 87.7% by mass (91% by volume) isopropyl alcohol. It has a slightly bitter taste, and is not safe to drink. [11] [12]
Isopropyl alcohol becomes increasingly viscous with decreasing temperature and freezes at −89.5 °C (−129.1 °F). [9] Mixtures with water have higher freezing points: 99% at −89.5 °C (−129.1 °F), 91% (the azeotrope) at −75.5 °C (−103.9 °F), and 70% at −61.7 °C (−79.1 °F). [13]
Isopropyl alcohol has a maximal absorbance at 205 nm in an ultraviolet-visible spectrum. [14] [15]
Isopropyl alcohol can be oxidized to acetone, which is the corresponding ketone. This can be achieved using oxidizing agents such as chromic acid, or by dehydrogenation of isopropyl alcohol over a heated copper catalyst:
Isopropyl alcohol is often used as both solvent and hydride source in the Meerwein-Ponndorf-Verley reduction and other transfer hydrogenation reactions. Isopropyl alcohol may be converted to 2-bromopropane using phosphorus tribromide, or dehydrated to propene by heating with sulfuric acid.
Like most alcohols, isopropyl alcohol reacts with active metals such as potassium to form alkoxides that are called isopropoxides. With titanium tetrachloride, isopropyl alcohol reacts to give titanium isopropoxide:
This and similar reactions are often conducted in the presence of base.
The reaction with aluminium is initiated by a trace of mercury to give aluminium isopropoxide. [16]
Isopropyl alcohol was first synthesized by the chemist Alexander William Williamson in 1853. He achieved this by heating a mixture of propene and sulfuric acid. Standard Oil produced isopropyl alcohol by hydrating propene. Isopropyl alcohol was oxidized to acetone for the preparation of cordite, a smokeless, low explosive propellant. [17]
In 1994, 1.5 million tonnes of isopropyl alcohol were produced in the United States, Europe, and Japan. [18] It is primarily produced by combining water and propene in a hydration reaction or by hydrogenating acetone. [18] [19] There are two routes for the hydration process and both processes require that the isopropyl alcohol be separated from water and other by-products by distillation. Isopropyl alcohol and water form an azeotrope, and simple distillation gives a material that is 87.9% by mass isopropyl alcohol and 12.1% by mass water. [20] Pure (anhydrous) isopropyl alcohol is made by azeotropic distillation of the wet isopropyl alcohol using either diisopropyl ether or cyclohexane as azeotroping agents. [18]
Small amounts of isopropyl alcohol are produced in the body in diabetic ketoacidosis. [21]
Indirect hydration reacts propene with sulfuric acid to form a mixture of sulfate esters. This process can use low-quality propene, and is predominant in the USA. These processes give primarily isopropyl alcohol rather than 1-propanol, because adding water or sulfuric acid to propene follows Markovnikov's rule. Subsequent hydrolysis of these esters by steam produces isopropyl alcohol, by distillation. Diisopropyl ether is a significant by-product of this process; it is recycled back to the process and hydrolyzed to give the desired product. [18]
Direct hydration reacts propene and water, either in gas or liquid phase, at high pressures in the presence of solid or supported acidic catalysts. This type of process usually requires higher-purity propylene (> 90%). [18] Direct hydration is more commonly used in Europe.
Isopropyl alcohol can be prepared via the hydrogenation of acetone, but this approach involves an extra step compared to the above methods, as acetone is itself normally prepared from propene via the cumene process. [18] IPA cost is primarily driven by raw material cost, and this way is economical when acetone is cheaper than propylene as a byproduct of phenol production (the coexistence of two ways on most markets allows them to balance the prices).
A known issue is the formation of MIBK and other self-condensation products. Raney nickel was one of the original industrial catalysts, modern catalysts are often supported bimetallic materials.
In 1990, 45,000 metric tonnes of isopropyl alcohol were used in the United States, mostly as a solvent for coatings or for industrial processes. In that year, 5400 metric tonnes were used for household purposes and in personal care products. Isopropyl alcohol is popular in particular for pharmaceutical applications, [18] due to its low toxicity. Some isopropyl alcohol is used as a chemical intermediate. Isopropyl alcohol may be converted to acetone, but the cumene process is more significant. [18]
Isopropyl alcohol dissolves a wide range of non-polar compounds. It evaporates quickly and the typically available grades tend to not leave behind oil traces when used as a cleaning fluid unlike some other common solvents. It is also relatively non-toxic. Thus, it is used widely as a solvent and as a cleaning fluid, especially where there are oils or oil based residues which are not easily cleaned with water, conveniently evaporating and (depending on water content and other variables) posing less of a risk of corrosion or rusting than plain water. Together with ethanol, n-butanol, and methanol, it belongs to the group of alcohol solvents.
Isopropyl alcohol is commonly used for cleaning eyeglasses, electrical contacts, audio or video tape heads, DVD and other optical disc lenses, bongs, [22] and for removing thermal paste from heatsinks on CPUs [23] and other IC packages.
Isopropyl alcohol is esterified to give isopropyl acetate, another solvent. It reacts with carbon disulfide and sodium hydroxide to give sodium isopropylxanthate, which has use as an herbicide and an ore flotation reagent. [24] Isopropyl alcohol reacts with titanium tetrachloride and aluminium metal to give titanium and aluminium isopropoxides, respectively, the former a catalyst, and the latter a chemical reagent. [18] This compound may serve as a chemical reagent in itself, by acting as a dihydrogen donor in transfer hydrogenation.
Rubbing alcohol, hand sanitizer, and disinfecting pads typically contain a 60–70% solution of isopropyl alcohol or ethanol in water. Water is required to open up membrane pores of bacteria, which acts as a gateway for isopropyl alcohol. A 75% v/v solution in water may be used as a hand sanitizer. [25] Isopropyl alcohol is used as a water-drying aid for the prevention of otitis externa, better known as swimmer's ear. [26]
Inhaled isopropyl alcohol can be used for treating nausea in some settings by placing a disinfecting pad under the nose. [27]
Although isopropyl alcohol can be used for anesthesia, its many negative attributes or drawbacks prohibit this use. Isopropyl alcohol can also be used similarly to ether as a solvent [28] or as an anesthetic by inhaling the fumes or orally. Early uses included using the solvent as general anesthetic for small mammals [29] and rodents by scientists and some veterinarians. However, it was soon discontinued, as many complications arose, including respiratory irritation, internal bleeding, and visual and hearing problems. In rare cases, respiratory failure leading to death in animals was observed.
Isopropyl alcohol is a major ingredient in "gas dryer" fuel additives. In significant quantities, water is a problem in fuel tanks, as it separates from gasoline and can freeze in the supply lines at low temperatures. Alcohol does not remove water from gasoline, but the alcohol solubilizes water in gasoline. Once soluble, water does not pose the same risk as insoluble water, as it no longer accumulates in the supply lines and freezes but is dissolved within the fuel itself. Isopropyl alcohol is often sold in aerosol cans as a windshield or door lock deicer. Isopropyl alcohol is also used to remove brake fluid traces from hydraulic braking systems, so that the brake fluid (usually DOT 3, DOT 4, or mineral oil) does not contaminate the brake pads and cause poor braking. Mixtures of isopropyl alcohol and water are also commonly used in homemade windshield washer fluid.
As a biological specimen preservative, isopropyl alcohol provides a comparatively non-toxic alternative to formaldehyde and other synthetic preservatives. Isopropyl alcohol solutions of 70–99% are used to preserve specimens.
Isopropyl alcohol is often used in DNA extraction. A lab worker adds it to a DNA solution to precipitate the DNA, which then forms a pellet after centrifugation. This is possible because DNA is insoluble in isopropyl alcohol.
Isopropyl alcohol is used as an additive in alkaline anisotropic etching of monocrystalline silicon, such as with potassium hydroxide or tetramethylammonium hydroxide. This process is used in texturing of silicon solar cells and microfabrication (e.g. in MEMS devices). Isopropyl alcohol increases the anisotropy of the etch by increasing the etch rate of [100] plane relative to higher indexed planes. [30]
Isopropyl alcohol vapor is denser than air and is flammable, with a flammability range of between 2% and 12.7% in air. It should be kept away from heat, sparks, and open flame. [31] Distillation of isopropyl alcohol over magnesium has been reported to form peroxides, which may explode upon concentration. [32] [33] Isopropyl alcohol can react with air and oxygen over time to form unstable peroxides that can explode. [34]
Isopropyl alcohol, via its metabolites, is somewhat more toxic than ethanol, but considerably less toxic than ethylene glycol or methanol. Death from ingestion or absorption of even relatively large quantities is rare. Both isopropyl alcohol and its metabolite, acetone, act as central nervous system (CNS) depressants. [35] Poisoning can occur from ingestion, inhalation, or skin absorption. [36] Symptoms of isopropyl alcohol poisoning include flushing, headache, dizziness, CNS depression, nausea, vomiting, anesthesia, hypothermia, low blood pressure, shock, respiratory depression, and coma. [35] Overdoses may cause a fruity odor on the breath as a result of its metabolism to acetone. [37] Isopropyl alcohol does not cause an anion gap acidosis, but it produces an osmolal gap between the calculated and measured osmolalities of serum, as do the other alcohols. [35] The findings of acetone without acidosis leads to the sine qua non of "ketosis without acidosis."
Isopropyl alcohol is oxidized to form acetone by alcohol dehydrogenase in the liver [35] and has a biological half-life in humans between 2.5 and 8.0 hours. [35] Unlike methanol or ethylene glycol poisoning, the metabolites of isopropyl alcohol are considerably less toxic, and treatment is largely supportive. Furthermore, there is no indication for the use of fomepizole, an alcohol dehydrogenase inhibitor, unless co-ingestion with methanol or ethylene glycol is suspected. [38]
In forensic pathology, people who have died as a result of diabetic ketoacidosis or alcoholic ketoacidosis, with no isopropyl alcohol ingestion, usually have detectable blood concentrations of isopropyl alcohol of 1 to 40 mg/dL, while those by fatal isopropyl alcohol ingestion usually have blood concentrations of hundreds of mg/dL. [21]
In chemistry, an alcohol, is a type of organic compound that carries at least one hydroxyl functional group bound to a saturated carbon atom. Alcohols range from the simple, like methanol and ethanol, to complex, like sugars and cholesterol. The presence of an OH group strongly modifies the properties of hydrocarbons, conferring hydrophilic (water-loving) properties. The OH group provides a site at which many reactions can occur.
Ethanol is an organic compound with the chemical formula CH3CH2OH. It is an alcohol, with its formula also written as C2H5OH, C2H6O or EtOH, where Et stands for ethyl. Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. In nature, grape-sugar breaks up by the action of fermentation into alcohol or carbonic acid, without anything being added. As a psychoactive depressant, it is the active ingredient in alcoholic beverages, and the second most consumed drug globally behind caffeine.
A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules, and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell.
Butanol (also called butyl alcohol) is a four-carbon alcohol with a formula of C4H9OH, which occurs in five isomeric structures (four structural isomers), from a straight-chain primary alcohol to a branched-chain tertiary alcohol; all are a butyl or isobutyl group linked to a hydroxyl group (sometimes represented as BuOH, sec-BuOH, i-BuOH, and t-BuOH). These are 1-butanol, two stereoisomers of sec-butyl alcohol, isobutanol and tert-butyl alcohol. Butanol is primarily used as a solvent and as an intermediate in chemical synthesis, and may be used as a fuel. Biologically produced butanol is called biobutanol, which may be n-butanol or isobutanol.
An azeotrope or a constant heating point mixture is a mixture of two or more liquids whose proportions cannot be changed by simple distillation. This happens because when an azeotrope is boiled, the vapour has the same proportions of constituents as the unboiled mixture. Knowing an azeotrope's behavior is important for distillation.
Petrochemicals are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewable sources such as maize, palm fruit or sugar cane.
Denatured alcohol, also known as methylated spirits, metho, or meths in Australia, Ireland, New Zealand, South Africa, and the United Kingdom, and as denatured rectified spirit, is ethanol that has additives to make it poisonous, bad-tasting, foul-smelling, or nauseating to discourage its recreational consumption. It is sometimes dyed so that it can be identified visually. Pyridine and methanol, each and together, make denatured alcohol poisonous; and denatonium makes it bitter.
The cumene process is an industrial process for synthesizing phenol and acetone from benzene and propylene. The term stems from cumene, the intermediate material during the process. It was invented by R. Ūdris and P. Sergeyev in 1942 (USSR), and independently by Heinrich Hock in 1944.
Fusel alcohols or fuselol, also sometimes called fusel oils in Europe, are mixtures of several higher alcohols produced as a by-product of alcoholic fermentation. The word Fusel is German for "bad liquor".
Butan-2-ol, or sec-butanol, is an organic compound with formula CH3CH(OH)CH2CH3. Its structural isomers are 1-butanol, isobutanol, and tert-butanol. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(−)-butan-2-ol and (S)-(+)-butan-2-ol. It is normally encountered as a 1:1 mixture of the two stereoisomers — a racemic mixture.
Acetone is an organic compound with the formula (CH3)2CO. It is the simplest and smallest ketone. It is a colorless, highly volatile, and flammable liquid with a characteristic pungent odour, very reminiscent of the smell of pear drops.
tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.
Reactive distillation is a process where the chemical reactor is also the still. Separation of the product from the reaction mixture does not need a separate distillation step which saves energy and materials. This technique can be useful for equilibrium-limited reactions such as esterification and ester hydrolysis reactions. Conversion can be increased beyond what is expected by the equilibrium due to the continuous removal of reaction products from the reactive zone. This approach can also reduce capital and investment costs.
The bioconversion of biomass to mixed alcohol fuels can be accomplished using the MixAlco process. Through bioconversion of biomass to a mixed alcohol fuel, more energy from the biomass will end up as liquid fuels than in converting biomass to ethanol by yeast fermentation.
Titanium isopropoxide, also commonly referred to as titanium tetraisopropoxide or TTIP, is a chemical compound with the formula Ti{OCH(CH3)2}4. This alkoxide of titanium(IV) is used in organic synthesis and materials science. It is a diamagnetic tetrahedral molecule. Titanium isopropoxide is a component of the Sharpless epoxidation, a method for the synthesis of chiral epoxides.
A cooling bath or ice bath, in laboratory chemistry practice, is a liquid mixture which is used to maintain low temperatures, typically between 13 °C and −196 °C. These low temperatures are used to collect liquids after distillation, to remove solvents using a rotary evaporator, or to perform a chemical reaction below room temperature.
Satratoxin-H, a trichothecene mycotoxin, is a naturally occurring toxin produced by the ascomycetes Stachybotrys chartarum and Trichoderma cornu-damae which is highly toxic to humans and animals. The clinical condition it causes is known as Stachybotrotoxicosis. It is related to the mycotoxin T-2, but unlike T-2 has not been reported to have been used as a chemical weapon.
In fire protection, an accelerant is any substance or mixture that accelerates or speeds the development and escalation of fire. Accelerants are often used to commit arson, and some accelerants may cause an explosion. Some fire investigators use the term "accelerant" to mean any substance that initiates and promotes a fire without implying intent or malice. The accelerant works by burning rapidly. As such, the accelerant itself is consumed in the process, and should not be considered as a catalyst. In Arson investigation, the significance of accelerant is to detect the presence of a such substance in order to proved that the fire is classified as an arson.
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.
In industrial paper-making processes, organosolv is a pulping technique that uses an organic solvent to solubilise lignin and hemicellulose. It has been considered in the context of both pulp and paper manufacture and biorefining for subsequent conversion of cellulose to fuel ethanol. The process was invented by Theodor Kleinert in 1968 as an environmentally benign alternative to kraft pulping.
Designations such as isopropanol, sec-butanol, and tert-butanol are incorrect because there are no hydrocarbons isopropane, sec-butane, and tert-butane to which the suffix "-ol" can be added; such names should be abandoned. Isopropyl alcohol, sec-butyl alcohol, and tert-butyl alcohol are, however, permissible (see Rule C-201.3) because the radicals isopropyl, sec-butyl, and tert-butyl do exist.