Novel method for the production of Zr-doped Beta-zeolites and their use in the production of 5-(hydroxymethyl)furfural etherified biofuels

A Beta zeolite with a high Al:Si molar ratio was dealuminated and the resulting silanol nests were functionalized with Zr to generate Lewis acid sites, for the catalytic transfer hydrogenation of the carbonyl group of 5-(hydroxymethyl)furfural (HMF), whose subsequent etherification with isopropanol led to the formation of 2,5-bis(isopropoxymethyl)furan, a potential biofuel. In this work, it was demonstrated that the parent zeolite was incapable of performing the reduction of HMF, instead directing the reaction towards the production of 5-(isopropoxymethyl)furfural (IMF) (90 % yield after 1 h at 180 ºC, with 150 mg of HMF). However, Zr-doped zeolites allowed the conversion of 5-(hydroxymethyl)furfural into its mono- and bis-etherified derivatives, and a 62 % yield of 2,5-bis(isopropoxymethyl)furan was achieved with the zeolite with a Si:Zr molar ratio of 30, after 5 h at 180 ºC. Zr loading was identified as an important factor in the catalyst deactivation due to the blocking of accessibility to the active sites required for the process at high Zr loading.