Isopropyl alcohol

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Isopropyl alcohol
Skeletal formula of isopropyl alcohol
Skeletal formula of isopropyl alcohol
Ball-and-stick model of isopropyl alcohol
Ball-and-stick model of isopropyl alcohol
Names
Preferred IUPAC name
Propan-2-ol[2]
Other names
2-Propanol
Isopropanol[1]
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 Edit this at Wikidata
1464
KEGG
RTECS number
  • NT8050000
UNII
UN number 1219
  • InChI=1S/C3H7OH/c1-3(2)4/h3-4H,1-2H3 checkY
    Key: KFZMGEQAYNKOFK-UHFFFAOYSA-N checkY
  • CC(O)C
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
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:
GHS07: Exclamation mark GHS02: Flammable
Danger
H225, H302, H319, H336
P210, P261, P305+P351+P338
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
3
0
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%
980 mg/m3 (TWA), 1225 mg/m3 (STEL)
Lethal dose or concentration (LD, LC):
  • 12800 mg/kg (dermal, rabbit)[8]
  • 3600 mg/kg (oral, mouse)
  • 5000 mg/kg (oral, rat)[8]
  • 2364 mg/kg (oral, rabbit)
  • 16,000 ppm (rat, 4 h)
  • 12,800 ppm (mouse, 3 h)[8]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 400 ppm (980 mg/m3)[7]
REL (Recommended)
 TWA 400 ppm (980 mg/m3), ST 500 ppm (1225 mg/m3)[7]
IDLH
(Immediate danger)
 2000 ppm[7]
Safety data sheet (SDS) [1]
Related compounds
Related alcohols
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).
checkY verify (what is checkY☒N ?)

Isopropyl alcohol (

flammable organic compound with a pungent alcoholic odor.[9]

Isopropyl alcohol, an organic

ethyl methyl ether
. They all have the formula C3H8O.

It was first synthesized in 1853 by

toxic effects including central nervous system depression and coma
, primarily treated through supportive measures.

Properties

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]

Reactions

Isopropyl alcohol can be

catalyst
:

(CH3)2CHOH → (CH3)2CO + H2

Isopropyl alcohol is often used as both solvent and

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:

TiCl4 + 4 (CH3)2CHOH → Ti(OCH(CH3)2)4 + 4 HCl

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]

History

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.

low explosive propellant.[17]

Production

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]

Biological

Small amounts of isopropyl alcohol are produced in the body in diabetic ketoacidosis.[21]

Indirect hydration

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]

CH3CH=CH2 + H2O H2SO4→ (CH3)2CHOH

Direct hydration

See also:
Heteropoly acid

Direct hydration reacts propene and water, either in gas or liquid

catalysts. This type of process usually requires higher-purity propylene (> 90%).[18]
Direct hydration is more commonly used in Europe.

Hydrogenation of acetone

Isopropyl alcohol can be prepared via the hydrogenation of acetone; however, 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 (acetone or propylene) cost. 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.

Uses

particles of radiation
.

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]

Solvent

Isopropyl alcohol dissolves a wide range of

n-butanol, and methanol
, it belongs to the group of alcohol solvents.

Isopropyl alcohol is commonly used for cleaning

CPUs[23] and other IC
packages.

Intermediate

Isopropyl alcohol is

esterified to give isopropyl acetate, another solvent. It reacts with carbon disulfide and sodium hydroxide to give sodium isopropylxanthate, a 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
.

Medical

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]

Early uses as an anesthetic

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.

Automotive

Isopropyl alcohol is a major ingredient in "gas dryer"

brake pads
and cause poor braking. Mixtures of isopropyl alcohol and water are also commonly used in homemade windshield washer fluid.

Laboratory

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.

Semiconductors

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]

Safety

Isopropyl alcohol vapor is denser than air and is

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]

Toxicology

Isopropyl alcohol, via its metabolites, is somewhat more toxic than ethanol, but considerably less toxic than

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
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 usually have blood concentrations of isopropyl alcohol of tens of mg/dL, while those by fatal isopropyl alcohol ingestion usually have blood concentrations of hundreds of mg/dL.[21]

References

  1. ^ "Alcohols Rule C-201.1". Nomenclature of Organic Chemistry (The IUPAC 'Blue Book'), Sections A, B, C, D, E, F, and H. Oxford: Pergamon Press. 1979. 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.
  2. ISBN 978-0-85404-182-4
    .
  3. ^ "Isopropanol_msds". chemsrc.com. Archived from the original on 10 March 2020. Retrieved 4 May 2018.
  4. doi:10.1139/v79-444
    .
  5. ^
    ISBN 978-0-07-073401-2
    .
  6. ^ Isopropyl alcohol toxicity
  7. ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0359". National Institute for Occupational Safety and Health (NIOSH).
  8. ^ a b c d "Isopropyl alcohol". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  9. ^ a b "Isopropanol". PubChem. Archived from the original on 12 February 2019. Retrieved 10 February 2019.
  10. ^ Doolittle, Arthur K. (1954). The Technology of Solvents and Plasticizers. New York: John Wiley & Sons, Inc. p. 628.
  11. ^
    ISBN 9780911910278
    .
  12. ISBN 978-0-471-41961-7
    .
  13. ^ "What is the Freezing Point of Isopropyl Alcohol?". Retrieved 18 December 2023.
  14. ^ "Isopropyl Alcohol, , Suitable for Liquid Chromatography, Extract/, UV-Spectrophotometry". VWR International. Archived from the original on 31 March 2016. Retrieved 25 August 2014.
  15. ^ "UV Cutoff" (PDF). University of Toronto. Archived (PDF) from the original on 8 October 2013. Retrieved 25 August 2014.
  16. ISBN 0471936235
    .
  17. ISBN 978-3-527-30289-5
    .
  18. ^
    ISBN 978-3527306732
    .
  19. ISBN 978-0471238966
    .
  20. ^ CRC Handbook of Chemistry and Physics, 44th ed. pp. 2143–2184.
  21. ^
    S2CID 21101240
    .
  22. ^ Directo-Meston, Danielle (9 February 2021). "How to Properly Clean Your Bong, According to Cannabis Experts". Rolling Stone. Retrieved 31 March 2024.
  23. ^ Intel application method arcticsilver.com
  24. ^ "Sodium Isopropyl Xanthate, SIPX, Xanthate". 3DChem.com. Archived from the original on 4 May 2012. Retrieved 17 June 2012.
  25. ^ "Guide to Local Production: WHO-recommended Handrub Formulations" (PDF). World Health Organization. August 2009. Archived (PDF) from the original on 19 May 2009. Retrieved 5 October 2020.
  26. ^ Otitis Externa (Swimmers Ear). Medical College of Wisconsin.
  27. PMID 30108075
    .
  28. PMID 20285822
    .
  29. ^ Society for Experimental Biology and Medicine (1922). Proceedings of the Society for Experimental Biology and Medicine, Volume 19. p. 85. Archived from the original on 20 December 2021. Retrieved 24 September 2016.
  30. ISSN 0924-4247
    .
  31. ^ "Isopropanol". Sigma-Aldrich. 19 January 2012. Archived from the original on 17 January 2021. Retrieved 6 July 2012.
  32. doi:10.1021/ed065pA226
    .
  33. ^ "Chemical safety: peroxide formation in 2-propanol". Chemical & Engineering News. 94 (31): 2. 1 August 2016. Archived from the original on 7 November 2017. Retrieved 2 November 2017.
  34. ^ "Hazardous Substance Fact Sheet" (PDF). Official Site of The State of New Jersey. Retrieved 4 November 2023.
  35. ^
    S2CID 30223646
    .
  36. PMID 34905533
    .
  37. PMID 12726989
    .
  38. ^ "Isopropyl alcohol poisoning". uptodate.com. Archived from the original on 10 October 2017. Retrieved 10 October 2017.

External links

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