Using microwave irradiation on formaldehyde to selectively produce sugars will help reduce the use of fossil resources and improve the sustainability of manufacturing processes.
With the exception of metals, the chemicals industry manufactures a large portion of its products using fossil fuels. To increase the sustainability of the chemicals sector, renewable biomass and even single-carbon sources like formaldehyde should be used.
In a recent study, researchers from Osaka University used microwave irradiation to improve the formose reaction’s applicability as a source of precursors for the manufacture of industrial chemicals.
The formose reaction, a well-known chemical synthesis from formaldehyde, yields a complicated mixture of sugars and sugar alcohols. Chemical engineers frequently require a pure substance for subsequent chemical processes, hence complex product combinations aren’t always practical. There are not many accounts of employing the formose process to make pure sugars or sugar alcohols with a large number of carbons, like six or more. Furthermore, there has been no reports that explicitly describe using microwave irradiation for the process. Microwave irradiation is a common and environmentally friendly method of accelerating and enhancing the selectivity of chemical reactions and the researchers are looking to using this to increase formose reaction’s usefulness in the chemical sector.
“The chemicals industry has a sustainability problem, and using formaldehyde as a chemical synthesis precursor can help solve this problem,” explained Akihito Hashidzume, lead author of the study. “Our updates to the formose reaction add substantial value to its utility in subsequent chemical syntheses.”
The results of exposing a formaldehyde solution reactant and calcium hydroxide catalyst to one minute of microwave irradiation at 150°C are being reported for the first time by the researchers. Five milliliters of reactant were transformed into a mixture of two sugars, one of which had six carbon atoms (hexose) and the other had seven (heptose). The reaction yield was around 100% without any reduction into smaller products.
“We hypothesise that the formose reaction in our system proceeds substantially on the surface of calcium hydroxide crystallites in the reaction mixture,” said Hashidzume. “Given that the formose reaction can also proceed on mineral or meteorite surfaces, our work also has intriguing possible implications for understanding the prebiotic synthesis of sugars.”
This work was able to increase the formose reaction’s applicability to the chemical industry, speeding up the reaction and resulting in a mixture of just two easily purifiable products. If scaling up to greater reaction volumes can be accomplished, the simple reaction design described here will greatly aid researchers in improving the sustainability of chemical feedstock production. [APBN]
Source: Hashidzume et al. (2023). Preferential formation of specific hexose and heptose in the formose reaction under microwave irradiation. RSC Advances, 13(6), 4089-4095.