Last updated
Preferred IUPAC name
Systematic IUPAC name
Other names
3D model (JSmol)
ECHA InfoCard 100.004.987 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
  • InChI=1S/C2H4O2/c3-1-2-4/h1,4H,2H2 Yes check.svgY
  • InChI=1/C2H4O2/c3-1-2-4/h1,4H,2H2
  • O=CCO
Molar mass 60.052 g/mol
Density 1.065 g/mL
Melting point 97 °C (207 °F; 370 K)
Boiling point 131.3 °C (268.3 °F; 404.4 K)
Related compounds
Related aldehydes


Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Glycolaldehyde is the organic compound with the formula HOCH2−CHO. It is the smallest possible molecule that contains both an aldehyde group (−CH=O) and a hydroxyl group (−OH). It is a highly reactive molecule that occurs both in the biosphere and in the interstellar medium. It is normally supplied as a white solid. Although it conforms to the general formula for carbohydrates, Cn(H2O)n, it is not generally considered to be a saccharide. [1]



Glycolaldehyde as a gas is a simple monomeric structure. As a solid and molten liquid, it exists as a dimer. Collins and George reported the equilibrium of glycolaldehyde in water by using NMR. [2] [3] In aqueous solution, it exists as a mixture of at least four species, which rapidly interconvert. [4]

Structures and distribution of glycolaldehyde as a 20% solution in water. Notice that the free aldehyde is a minor component. Glyoxaldehyde-in20-D2O.png
Structures and distribution of glycolaldehyde as a 20% solution in water. Notice that the free aldehyde is a minor component.

In acidic or basic solution, the compound undergoes reversible tautomerization to form 1,2-dihydroxyethene. [5]

It is the only possible diose, a 2-carbon monosaccharide, although a diose is not strictly a saccharide. While not a true sugar, it is the simplest sugar-related molecule. [6] It is reported to taste sweet. [7]


Glycolaldehyde is the second most abundant compound formed when preparing pyrolysis oil (up to 10% by weight). [8]

Glycolaldehyde can be synthesized by the oxidation of ethylene glycol using hydrogen peroxide in the presence of iron(II) sulfate. [9]


It can form by action of ketolase on fructose 1,6-bisphosphate in an alternate glycolysis pathway. This compound is transferred by thiamine pyrophosphate during the pentose phosphate shunt.

In purine catabolism, xanthine is first converted to urate. This is converted to 5-hydroxyisourate, which decarboxylates to allantoin and allantoic acid. After hydrolyzing one urea, this leaves glycolureate. After hydrolyzing the second urea, glycolaldehyde is left. Two glycolaldehydes condense to form erythrose 4-phosphate,[ citation needed ] which goes to the pentose phosphate shunt again.

Role in formose reaction

Glycolaldehyde is an intermediate in the formose reaction. In the formose reaction, two formaldehyde molecules condense to make glycolaldehyde. Glycolaldehyde then is converted to glyceraldehyde, presumably via initial tautomerization. [10] The presence of this glycolaldehyde in this reaction demonstrates how it might play an important role in the formation of the chemical building blocks of life. Nucleotides, for example, rely on the formose reaction to attain its sugar unit. Nucleotides are essential for life, because they compose the genetic information and coding for life.

Theorized role in abiogenesis

It is often invoked in theories of abiogenesis. [11] [12] In the laboratory, it can be converted to amino acids [13] and short dipeptides [14] may have facilitated the formation of complex sugars. For example, L-valyl-L-valine was used as a catalyst to form tetroses from glycolaldehyde. Theoretical calculations have additionally shown the feasibility of dipeptide-catalyzed synthesis of pentoses. [15] This formation showed stereospecific, catalytic synthesis of D-ribose, the only naturally occurring enantiomer of ribose. Since the detection of this organic compound, many theories have been developed related various chemical routes to explain its formation in stellar systems.

Formation of glycolaldehyde in star dust Formation of Glycolaldehyde in star dust.png
Formation of glycolaldehyde in star dust

It was found that UV-irradiation of methanol ices containing CO yielded organic compounds such as glycolaldehyde and methyl formate, the more abundant isomer of glycolaldehyde. The abundances of the products slightly disagree with the observed values found in IRAS 16293-2422, but this can be accounted for by temperature changes. Ethylene Glycol and glycolaldehyde require temperatures above 30 K. [16] [17] The general consensus among the astrochemistry research community is in favor of the grain surface reaction hypothesis. However, some scientists believe the reaction occurs within denser and colder parts of the core. The dense core will not allow for irradiation as stated before. This change will completely alter the reaction forming glycolaldehyde. [18]

Formation in space

Artistic depiction of sugar molecules in the gas surrounding a young Sun-like star. Sugar molecules in the gas surrounding a young Sun-like star.jpg
Artistic depiction of sugar molecules in the gas surrounding a young Sun-like star.

The different conditions studied indicate how problematic it could be to study chemical systems that are light-years away. The conditions for the formation of glycolaldehyde are still unclear. At this time, the most consistent formation reactions seems to be on the surface of ice in cosmic dust.

Glycolaldehyde has been identified in gas and dust near the center of the Milky Way galaxy, [20] in a star-forming region 26000 light-years from Earth, [21] and around a protostellar binary star, IRAS 16293-2422 , 400 light years from Earth. [22] [23] Observation of in-falling glycolaldehyde spectra 60 AU from IRAS 16293-2422 suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation. [17]

Detection in space

The interior region of a dust cloud is known to be relatively cold. With temperatures as cold as 4 Kelvin the gases within the cloud will freeze and fasten themselves to the dust, which provides the reaction conditions conducive for the formation of complex molecules such as glycolaldehyde. When a star has formed from the dust cloud, the temperature within the core will increase. This will cause the molecules on the dust to evaporate and be released. The molecule will emit radio waves that can be detected and analyzed. The Atacama Large Millimeter/submillimeter Array (ALMA) first detected glycolaldehyde. ALMA consists of 66 antennas that can detect the radio waves emitted from cosmic dust. [24]

On October 23, 2015, researchers at the Paris Observatory announced the discovery of glycolaldehyde and ethyl alcohol on Comet Lovejoy, the first such identification of these substances in a comet. [25] [26]

Related Research Articles

<span class="mw-page-title-main">Metabolism</span> Set of chemical reactions in organisms

Metabolism is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary metabolism.

<span class="mw-page-title-main">Miller–Urey experiment</span> Chemical experiment that simulated conditions on the early Earth and tested the origin of life

The Miller–Urey experiment (or Miller experiment) is a famous chemistry experiment that simulated the conditions thought at the time (1952) to be present in the atmosphere of the early, prebiotic Earth, in order to test the hypothesis of the chemical origin of life under those conditions. The experiment used water (H2O), methane (CH4), ammonia (NH3), hydrogen (H2), and an electric arc (the latter simulating hypothesized lightning).

<span class="mw-page-title-main">Nucleotide</span> Biological molecules that form the building blocks of nucleic acids

Nucleotides are organic molecules composed of a nitrogenous base, a pentose sugar and a phosphate. They serve as monomeric units of the nucleic acid polymers – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both of which are essential biomolecules within all life-forms on Earth. Nucleotides are obtained in the diet and are also synthesized from common nutrients by the liver.

<span class="mw-page-title-main">RNA world</span> Hypothetical stage in the early evolutionary history of life on Earth

The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.

<span class="mw-page-title-main">Astrochemistry</span> Study of molecules in the Universe and their reactions

Astrochemistry is the study of the abundance and reactions of molecules in the Universe, and their interaction with radiation. The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar System and the interstellar medium. The study of the abundance of elements and isotope ratios in Solar System objects, such as meteorites, is also called cosmochemistry, while the study of interstellar atoms and molecules and their interaction with radiation is sometimes called molecular astrophysics. The formation, atomic and chemical composition, evolution and fate of molecular gas clouds is of special interest, because it is from these clouds that solar systems form.

<span class="mw-page-title-main">Stanley Miller</span> American scientist (1930–2007)

Stanley Lloyd Miller was an American chemist who made landmark experiments in the origin of life by demonstrating that a wide range of vital organic compounds can be synthesized by fairly simple chemical processes from inorganic substances. In 1952 he carried out the Miller–Urey experiment, which showed that complex organic molecules could be synthesised from inorganic precursors. The experiment was widely reported, and provided support for the idea that the chemical evolution of the early Earth had led to the natural synthesis of chemical building blocks of life from inanimate inorganic molecules. He has been described as the "father of prebiotic chemistry".

<span class="mw-page-title-main">Cosmochemistry</span> Study of the chemical composition of matter in the universe

Cosmochemistry or chemical cosmology is the study of the chemical composition of matter in the universe and the processes that led to those compositions. This is done primarily through the study of the chemical composition of meteorites and other physical samples. Given that the asteroid parent bodies of meteorites were some of the first solid material to condense from the early solar nebula, cosmochemists are generally, but not exclusively, concerned with the objects contained within the Solar System.

<span class="mw-page-title-main">Tholin</span> Class of molecules formed by ultraviolet irradiation of organic compounds

Tholins are a wide variety of organic compounds formed by solar ultraviolet or cosmic ray irradiation of simple carbon-containing compounds such as carbon dioxide, methane or ethane, often in combination with nitrogen or water. Tholins are disordered polymer-like materials made of repeating chains of linked subunits and complex combinations of functional groups, typically nitriles and hydrocarbons and their degraded forms such as amines and phenyls. Tholins do not form naturally on modern-day Earth, but they are found in great abundance on the surfaces of icy bodies in the outer Solar System, and as reddish aerosols in the atmospheres of outer Solar System planets and moons.

<span class="mw-page-title-main">Ribonucleotide</span> Nucleotide containing ribose as its pentose component

In biochemistry, a ribonucleotide is a nucleotide containing ribose as its pentose component. It is considered a molecular precursor of nucleic acids. Nucleotides are the basic building blocks of DNA and RNA. Ribonucleotides themselves are basic monomeric building blocks for RNA. Deoxyribonucleotides, formed by reducing ribonucleotides with the enzyme ribonucleotide reductase (RNR), are essential building blocks for DNA. There are several differences between DNA deoxyribonucleotides and RNA ribonucleotides. Successive nucleotides are linked together via phosphodiester bonds.

Homochirality is a uniformity of chirality, or handedness. Objects are chiral when they cannot be superposed on their mirror images. For example, the left and right hands of a human are approximately mirror images of each other but are not their own mirror images, so they are chiral. In biology, 19 of the 20 natural amino acids are homochiral, being L-chiral (left-handed), while sugars are D-chiral (right-handed). Homochirality can also refer to enantiopure substances in which all the constituents are the same enantiomer, but some sources discourage this use of the term.

<span class="mw-page-title-main">PAH world hypothesis</span> Hypothesis about the origin of life

The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, including in comets, and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA molecules, leading into the RNA world. However, as yet, the hypothesis is untested.

The formose reaction, discovered by Aleksandr Butlerov in 1861, and hence also known as the Butlerov reaction, involves the formation of sugars from formaldehyde. The term formose is a portmanteau of formaldehyde and aldose.

<span class="mw-page-title-main">Ribose 5-phosphate</span> Chemical compound

Ribose 5-phosphate (R5P) is both a product and an intermediate of the pentose phosphate pathway. The last step of the oxidative reactions in the pentose phosphate pathway is the production of ribulose 5-phosphate. Depending on the body's state, ribulose 5-phosphate can reversibly isomerize to ribose 5-phosphate. Ribulose 5-phosphate can alternatively undergo a series of isomerizations as well as transaldolations and transketolations that result in the production of other pentose phosphates as well as fructose 6-phosphate and glyceraldehyde 3-phosphate.

<span class="mw-page-title-main">Albert Eschenmoser</span> Swiss organic chemist

Albert Jakob Eschenmoser (born 5 August 1925) is a Swiss organic chemist, best known for his work on the synthesis of complex heterocyclic natural compounds, most notably vitamin B12. In addition to his significant contributions to the field of organic synthesis, Eschenmoser pioneered work in the Origins of Life (OoL) field with work on the synthetic pathways of artificial nucleic acids. Before retiring in 2009, Eschenmoser held tenured teaching positions at the ETH Zurich and The Skaggs Institute for Chemical Biology at The Scripps Research Institute in La Jolla, California as well as visiting professorships at the University of Chicago, Cambridge University, and Harvard.

<span class="mw-page-title-main">Abiogenesis</span> Natural process by which life arises from non-living matter

In biology, abiogenesis or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but a process of increasing complexity involving the formation of a habitable planet, the prebiotic synthesis of organic molecules, molecular self-replication, self-assembly, autocatalysis, and the emergence of cell membranes. Many proposals have been made for different stages of the process.

<span class="mw-page-title-main">IRAS 16293−2422</span> Star in the constellation Ophiuchus

IRAS 16293–2422 is a binary system consisting of at least two forming protostars A and B, separated by a distance of 700 astronomical units (au), both having masses similar to that of the Sun. It is located in the Rho Ophiuchi star-forming region, at a distance of 140 parsecs (pc). Astronomers using the ALMA array found glycolaldehyde — a simple form of sugar — in the gas surrounding the star. This discovery was the first time sugar has been found in space around a solar-type star on scales corresponding to the distance between Sun and Uranus - i.e., the scales where a planet-forming disk is expected to arise. The discovery shows that the building blocks of life may in the right place, at the right time, to be included in planets forming around the star.

Formamide-based prebiotic chemistry is a reconstruction of the beginnings of life on Earth, assuming that formamide could accumulate in sufficiently high amounts to serve as the building block and reaction medium for the synthesis of the first biogenic molecules.

Pseudo-panspermia is a well-supported hypothesis for a stage in the origin of life. The theory first asserts that many of the small organic molecules used for life originated in space. It continues that these organic molecules were distributed to planetary surfaces, where life then emerged on Earth and perhaps on other planets. Pseudo-panspermia differs from the fringe theory of panspermia, which asserts that life arrived on Earth from distant planets.

A scenario is a set of related concepts pertinent to the origin of life (abiogenesis), such as the iron-sulfur world. Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come into existence. These include hypothesized ancient environments that might have been favourable for the origin of life, and possible biochemical mechanisms.

<span class="mw-page-title-main">Prebiotic atmosphere</span>

The prebiotic atmosphere is the second atmosphere present on Earth before today's biotic, oxygen-rich third atmosphere, and after the first atmosphere of Earth's formation. The formation of the Earth, roughly 4.5 billion years ago, involved multiple collisions and coalescence of planetary embryos. This was followed by a <100 million year period on Earth where a magma ocean was present, the atmosphere was mainly steam, and surface temperatures reached up to 8,000 K (14,000 °F). Earth's surface then cooled and the atmosphere stabilized, establishing the prebiotic atmosphere. The environmental conditions during this time period were quite different from today: the Sun was ~30% dimmer overall yet brighter at ultraviolet and x-ray wavelengths, there was a liquid ocean, it is unknown if there were continents but oceanic islands were likely, Earth's interior chemistry was different, and there was a larger flux of impactors hitting Earth's surface.


  1. Mathews, Christopher K. (2000). Biochemistry. Van Holde, K. E. (Kensal Edward), 1928-, Ahern, Kevin G. (3rd ed.). San Francisco, Calif.: Benjamin Cummings. p. 280. ISBN   978-0805330663. OCLC   42290721.
  2. "Prediction of Isomerization of Glycolaldehyde In Aqueous Solution by IBM RXN – Artificial Intelligence for Chemistry" . Retrieved 2019-11-19.
  3. Collins, G. C. S.; George, W. O. (1971). "Nuclear magnetic resonance spectra of glycolaldehyde". Journal of the Chemical Society B: Physical Organic: 1352. doi:10.1039/j29710001352. ISSN   0045-6470.
  4. Yaylayan, Varoujan A.; Harty-Majors, Susan; Ismail, Ashraf A. (1998). "Investigation of the mechanism of dissociation of glycolaldehyde dimer (2,5-dihydroxy-1,4-dioxane) by FTIR spectroscopy". Carbohydrate Research. 309: 31–38. doi:10.1016/S0008-6215(98)00129-3.
  5. Fedoroňko, Michal; Temkovic, Peter; Königstein, Josef; Kováčik, Vladimir; Tvaroška, Igor (1 December 1980). "Study of the kinetics and mechanism of the acid-base-catalyzed enolization of hydroxyacetaldehyde and methoxyacetaldehyde". Carbohydrate Research. 87 (1): 35–50. doi:10.1016/S0008-6215(00)85189-7.
  6. Carroll, P.; Drouin, B.; Widicus Weaver, S. (2010). "The Submillimeter Spectrum of Glycolaldehyde" (PDF). Astrophys. J. 723 (1): 845–849. Bibcode:2010ApJ...723..845C. doi:10.1088/0004-637X/723/1/845. S2CID   30104627.
  7. Shallenberger, R. S. (2012-12-06). Taste Chemistry. Springer Science & Business Media. ISBN   9781461526667.
  8. Moha, Dinesh; Charles U. Pittman, Jr.; Philip H. Steele (10 March 2006). "Pyrolysis of Wood/Biomass for Bio-oil: A Critical Review". Energy & Fuels. 206 (3): 848–889. doi:10.1021/ef0502397. S2CID   49239384.
  9. {{Hans Peter Latscha, Uli Kazmaier und Helmut Alfons Klein : Organic Chemistry: Chemistry Basiswissen-II '. Springer, Berlin; 6, vollständig überarbeitete Auflage 2008, ISBN   978-3-540-77106-7, S. 217}}
  10. Kleimeier, N. Fabian; Eckhardt, André K.; Kaiser, Ralf I. (August 18, 2021). "Identification of Glycolaldehyde Enol (HOHC═CHOH) in Interstellar Analogue Ices". J. Am. Chem. Soc. 143 (34): 14009–14018. doi:10.1021/jacs.1c07978. PMID   34407613. S2CID   237215450.{{cite journal}}: CS1 maint: date and year (link)
  11. Kim, H.; Ricardo, A.; Illangkoon, H. I.; Kim, M. J.; Carrigan, M. A.; Frye, F.; Benner, S. A. (2011). "Synthesis of Carbohydrates in Mineral-Guided Prebiotic Cycles". Journal of the American Chemical Society. 133 (24)): 9457–9468. doi:10.1021/ja201769f. PMID   21553892.
  12. Benner, S. A.; Kim, H.; Carrigan, M. A. (2012). "Asphalt, Water, and the Prebiotic Synthesis of Ribose, Ribonucleosides, and RNA". Accounts of Chemical Research. 45 (12): 2025–2034. doi:10.1021/ar200332w. PMID   22455515. S2CID   10581856.
  13. Pizzarello, Sandra; Weber, A. L. (2004). "Prebiotic amino acids as asymmetric catalysts". Science. 303 (5661): 1151. CiteSeerX . doi:10.1126/science.1093057. PMID   14976304. S2CID   42199392.
  14. Weber, Arthur L.; Pizzarello, S. (2006). "The peptide-catalyzed stereospecific synthesis of tetroses: A possible model for prebiotic molecular evolution". Proceedings of the National Academy of Sciences of the USA. 103 (34): 12713–12717. Bibcode:2006PNAS..10312713W. doi: 10.1073/pnas.0602320103 . PMC   1568914 . PMID   16905650.
  15. Cantillo, D.; Ávalos, M.; Babiano, R.; Cintas, P.; Jiménez, J. L.; Palacios, J. C. (2012). "On the Prebiotic Synthesis of D-Sugars Catalyzed by L-Peptides Assessments from First-Principles Calculations". Chemistry: A European Journal. 18 (28): 8795–8799. doi:10.1002/chem.201200466. PMID   22689139.
  16. Öberg, K. I.; Garrod, R. T.; van Dishoeck, E. F.; Linnartz, H. (September 2009). "Formation rates of complex organics in UV irradiation CH_3OH-rich ices. I. Experiemtns". Astronomy and Astrophysics. 504 (3): 891–913. arXiv: 0908.1169 . Bibcode:2009A&A...504..891O. doi:10.1051/0004-6361/200912559. S2CID   7746611.
  17. 1 2 Jørgensen, J. K.; Favre, C.; Bisschop, S.; Bourke, T.; Dishoeck, E.; Schmalzl, M. (2012). "Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA" (PDF). The Astrophysical Journal. eprint. 757 (1): L4. arXiv: 1208.5498 . Bibcode:2012ApJ...757L...4J. doi:10.1088/2041-8205/757/1/L4. S2CID   14205612.
  18. Woods, P. M; Kelly, G.; Viti, S.; Slater, B.; Brown, W. A.; Puletti, F.; Burke, D. J.; Raza, Z. (2013). "Glycolaldehyde Formation via the Dimerisation of the Formyl Radical". The Astrophysical Journal. 777 (50): 90. arXiv: 1309.1164 . Bibcode:2013ApJ...777...90W. doi:10.1088/0004-637X/777/2/90. S2CID   13969635.
  19. "Sweet Result from ALMA". ESO Press Release. Retrieved 3 September 2012.
  20. Hollis, J.M., Lovas, F.J., & Jewell, P.R. (2000). "Interstellar Glycolaldehyde: The First Sugar". The Astrophysical Journal. 540 (2): 107–110. Bibcode:2000ApJ...540L.107H. doi: 10.1086/312881 .{{cite journal}}: CS1 maint: multiple names: authors list (link)
  21. Beltran, M. T.; Codella, C.; Viti, S.; Neri, R.; Cesaroni, R. (November 2008). "First detection of glycolaldehyde outside the Galactic Center". eprint arXiv:0811.3821.{{cite journal}}: Cite journal requires |journal= (help)[ permanent dead link ]
  22. Than, Ker (August 29, 2012). "Sugar Found In Space". National Geographic. Retrieved August 31, 2012.
  23. Staff (August 29, 2012). "Sweet! Astronomers spot sugar molecule near star". AP News . Retrieved August 31, 2012.
  24. "Building blocks of life found around young star" . Retrieved December 11, 2013.
  25. Biver, Nicolas; Bockelée-Morvan, Dominique; Moreno, Raphaël; Crovisier, Jacques; Colom, Pierre; Lis, Dariusz C.; Sandqvist, Aage; Boissier, Jérémie; Despois, Didier; Milam, Stefanie N. (2015). "Ethyl alcohol and sugar in comet C/2014 Q2 (Lovejoy)". Science Advances. 1 (9): e1500863. arXiv: 1511.04999 . Bibcode:2015SciA....1E0863B. doi:10.1126/sciadv.1500863. PMC   4646833 . PMID   26601319.
  26. "Researchers find ethyl alcohol and sugar in a comet ! -".