Glycidol is an organic compound with the formula HOCH2CHOCH2. The molecule contains both epoxide and alcohol functional groups. Being simple to make and bifunctional, it has a variety of industrial uses. The compound is a colorless, slightly viscous liquid that is slightly unstable and is not often encountered in pure form.[7]

Glycidol
Glycidol
Names
Preferred IUPAC name
Oxiranylmethanol
Other names
Glycidol
2,3-Epoxy-1-propanol
3-Hydroxypropylene oxide
Epoxypropyl alcohol
Hydroxymethyl ethylene oxide
2-Hydroxymethyl oxiran
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.008.300 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C3H6O2/c4-1-3-2-5-3/h3-4H,1-2H2 checkY
    Key: CTKINSOISVBQLD-UHFFFAOYSA-N checkY
  • InChI=1/C3H6O2/c4-1-3-2-5-3/h3-4H,1-2H2
    Key: CTKINSOISVBQLD-UHFFFAOYAN
  • OCC1OC1
Properties
C3H6O2
Molar mass 74.079 g·mol−1
Appearance Viscous liquid
Density 1.1143 g/cm3[1]
Melting point −54 °C (−65 °F; 219 K)[3]
Boiling point 167 °C (333 °F; 440 K) (decomposes)[1]
miscible[2]
Vapor pressure 0.9 mmHg (25°C)[2]
Hazards
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxideSpecial hazards (white): no code
4
2
3
Flash point 66 °C (151 °F; 339 K)[3]
Lethal dose or concentration (LD, LC):
420 mg/kg (oral, rat)[3][4]
1980 mg/kg (dermal, rabbit)[3][5]
450 ppm (mouse, 4 hr)
580 ppm (rat, 8 hr)[6]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 50 ppm (150 mg/m3)[2]
REL (Recommended)
TWA 25 ppm (75 mg/m3)[2]
IDLH (Immediate danger)
150 ppm[2]
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis and applications

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Glycidol is prepared by the epoxidation of allyl alcohol. A typical catalyst is tungstic acid, and a typical O-atom source is aqueous peroxyacetic acid.[8]

Some useful products derived from glycidol are 2,3-epoxypropyloxy chloroformate (from phosgene) and glycidyl urethanes (by addition of isocyanates:[8]

HOCH2CH(O)CH2 + COCl2 → ClC(O)OCH2CH(O)CH2 + HCl
HOCH2CH(O)CH2 + RNCO → RNHC(O)OCH2CH(O)CH2

Glycidol is used as a chemical intermediate in the synthesis of other glycidyl ethers, esters, and amines.[9]

Glycidol can be O-benzylated in the presence of strong base.[10] More typically, such glycidol ethers are produced by reaction of epichlorohydrin with alkoxides.[11]

Glycidol is a precursor to diproqualone (by alkylation of 2-methylquinazolin-4(3H)-one) and dyphylline (by alkylation of theophylline).

Occurrence

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Glycidyl fatty acid esters that are thought to contaminate some edible oils could be a source of traces of glycidol in the diet. These esters are formed during the deodorization step of edible oil refining, which uses vapor and high temperatures to remove impurities. The reaction conditions in that step can allow monoglyceride and diglycerides (MAG, DAG) naturally present in the oil to rearrange into glycidyl fatty acid esters.[12]

Safety

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Glycidol is an irritant of the skin, eyes, mucous membranes, and upper respiratory tract. Exposure to glycidol may also cause central nervous system depression, followed by central nervous system stimulation.[13] It is listed as an IARC Group 2A Agent, meaning that it is "probably carcinogenic to humans".[14] In regards to occupational exposures, the Occupational Safety and Health Administration has set a permissible exposure limit at 50 ppm over an eight-hour work shift, while the National Institute for Occupational Safety and Health recommends a limit at 25 ppm over an eight-hour work shift.[15]

See also

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References

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  1. ^ a b Merck Index, 11th Edition, 4385
  2. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0303". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b c d Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  4. ^ Food and Cosmetics Toxicology. Vol. 19, Pg. 347, 1981
  5. ^ AMA Archives of Industrial Health. Vol. 14, Pg. 250, 1956
  6. ^ "Glycidol". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  7. ^ Johnson, Roy A.; Burgos-Lepley, Carmen E. (2001). "Glycidol". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rg005. ISBN 0-471-93623-5.
  8. ^ a b Guenter Sienel, Robert Rieth, Kenneth T. Rowbottom "Epoxides" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a09_531
  9. ^ Glycidol at chemicalland21.com
  10. ^ Bruce H. Lipshutz, Robert Moretti, and Robert Crow (1990). "Mixed Higher-Order Cyanocuprate-Induced Epoxide Openings: 1-Benzyloxy-4-Penten-2-Ol". Organic Syntheses. 69: 80. doi:10.15227/orgsyn.069.0080.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  11. ^ Sutter, Marc; Silva, Eric Da; Duguet, Nicolas; Raoul, Yann; Métay, Estelle; Lemaire, Marc (2015). "Glycerol Ether Synthesis: A Bench Test for Green Chemistry Concepts and Technologies" (PDF). Chemical Reviews. 115 (16): 8609–8651. doi:10.1021/cr5004002. PMID 26196761.
  12. ^ Cheng, Wei-wei; Liu, Guo-qin; Wang, Li-qing; Liu, Zeng-she (2017). "Glycidyl Fatty Acid Esters in Refined Edible Oils: A Review on Formation, Occurrence, Analysis, and Elimination Methods". Comprehensive Reviews in Food Science and Food Safety. 16 (2): 263–281. doi:10.1111/1541-4337.12251. ISSN 1541-4337. PMID 33371535.
  13. ^ "OSHA guidelines for glycidol". Archived from the original on 2012-09-25. Retrieved 2006-10-20.
  14. ^ "List of Classifications, Agents classified by the IARC Monographs, Volumes 1–124". IARC Monographs on the Evaluation of Risk to Humans. IARC. July 7, 2019. Retrieved July 14, 2019.
  15. ^ CDC - NIOSH Pocket Guide to Chemical Hazards

Further reading

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