Several sulfonated polymers, which are typical Brønsted acid catalysts, have been employed in the production of
two biofuels: 5-ethoxymethylfurfural (EMF) and ethyl levulinate (EL) as main byproduct, and the catalytic results
have been attributed to their different chemical and morphological properties. The Purolite CT275DR attained
the best results from 5-hydroxymethylfurfural (HMF) with a 63% EMF yield after 16 h at 100 ◦C thanks to their
more abundant superficial acid sites. Moreover, Purolite CT275DR was able to efficiently dehydrate and etherify
fructose, with a total EMF plus EL yield of 65% after 24 h at 100 ◦C. When glucose or galactose were used as
feedstock, alumina was utilized to provide Lewis acid sites, necessary for the transformation of aldoses in so-
lution enabling a combined biofuel yield (EMF plus EL) of 40% from glucose after 24 h at 140 ◦C. With the study
of the role of each catalyst, both Brønsted and Lewis acid catalysts (resin and alumina, respectively) were
required to obtain considerable EMF yields from aldoses. The reutilization of the catalysts employed for 5 cat-
alytic runs demonstrated that Purolite CT275DR suffers no appreciable loss of activity, but alumina showed
progressive losses in activity in each cycle due to carbonaceous deposits and catalyst loss.Funding for open access charge: Universidad de Málaga / CBUA
This research was funded by the Spanish Ministry of Innovation,
Science and Universities (RTI2018-094918-B-C44), FEDER (European
Union) funds (RTI2018-094918-B-C44 and UMA18-FEDERJA-171) and
Malaga University. Authors thank to Universidad de M ́alaga/CBUA for
funding for open access charge. C.G.S. acknowledges FEDER funds for
her postdoctoral contract (UMA18-FEDERJA-171). B.T.O. acknowledges
the Ministerio de Universidades for his predoctoral contract (FPU20/
02334
