Researchers from Shanghai University of Engineering Science, in collaboration with a scientist from Ariel University in Israel, have developed a catalytic process that converts glycerol, a major by-product of biodiesel production, into glycidol, a high-value chemical building block, Bioengineer.org reported.
The study, published in Catalysis Letters, uses glycerol and dimethyl carbonate as feedstocks and a ternary mixed-metal oxide catalyst made from cobalt oxide, ceria and alumina. The researchers prepared the catalyst through a coprecipitation method.
Under optimised conditions, the catalyst with a cobalt-to-cerium-to-aluminium atomic ratio of 1:1:2 achieved 99.9% glycerol conversion and 81.3% selectivity to glycidol. The reaction was carried out at 160°C for seven hours, using a glycerol-to-dimethyl carbonate molar ratio of 1:3 and a catalyst loading of 7% by weight.
Glycerol is generated in large quantities during biodiesel production, with roughly one kilogram of glycerol produced for every 10 kilograms of biodiesel. While biodiesel has established markets, the rapid accumulation of glycerol as a co-product has created a need for economically viable ways to convert it into higher-value chemicals.
The researchers’ process addresses this challenge by using glycerol as a feedstock for producing glycidol, a reactive epoxide compound used in the manufacture of surfactants, epoxy resins, pharmaceutical intermediates, functional polymers and other specialty chemicals.
Glycidol contains a strained three-membered oxirane ring, which gives it high chemical reactivity and makes it useful as a building block in chemical synthesis. Conventional glycidol production generally involves multi-step processes using halohydrin intermediates, chlorination or dehydrohalogenation, which can generate corrosive salt waste.
The researchers said the catalytic conversion of glycerol and dimethyl carbonate offers a potentially more sustainable route by combining a biodiesel-derived surplus material with a relatively benign feedstock in a single reaction vessel.
The reported combination of near-complete glycerol conversion and high glycidol selectivity demonstrates the potential of heterogeneous catalysis to add value to glycerol and create new chemical products from biodiesel industry by-products.
