For the first occasion, scientists have successfully synthesised and characterised methanetetrol — the sole conceivable structure where four hydroxyl groups are attached to one carbon atom. Widely referred to as orthocarbonic acid, this elusive molecule was initially postulated in 1922 by physical chemist Ernst Wilke. While tetravalent structures such as orthocarbonic esters are acknowledged for their stability and prevalence, methanetetrol has historically gone undetected due to its unstable characteristics.
Led by Ralf Kaiser from the University of Hawaii at Mānoa, US, the research group implemented an innovative synthetic approach. Drawing parallels with earlier studies on methanetriol synthesis, they utilized interstellar-like conditions in a laboratory environment. By exposing a mixture of carbon dioxide and water to strong electron beams under ultra-high vacuum settings and temperatures close to absolute zero, they stimulated the unusual chemical reactions required to produce methanetetrol.
This synthetic setting minimizes molecular collisions, averting the usual breakdown into water and carbonic acid. Moreover, the irradiation of ‘interstellar ice’ facilitated the simultaneous synthesis and detection of the tetra-alcohol. The team combined both computational and experimental techniques to confirm methanetetrol’s existence. Experimental approaches included photoionisation using UV light to break apart molecules, alongside mass spectrometry for identifying various ions. Although fragment identification could potentially lead to discrepancies, isotopic substitution clarified the findings. Labeled carbon dioxide and deuterium oxide produced unique peaks linked to methanetetrol, affirming the discovery, as stated by Kaiser.
Following the success of this experimental achievement, Kaiser is preparing for his next formidable challenge: synthesising tetrahydroperoxymethane, a compound comprising methane attached to four hydroperoxyl groups. This upcoming project promises to be another remarkable scientific hurdle.