Heterogeneous catalytic oxidation of 5-hydroxymethylfurfural (HMF) with molecular oxygen to 2,5-diformylfuran (DFF) was performed on aluminium oxide-supported ruthenium catalysts (Ru/Al 2 O 3 ). The ruthenium catalysts were analyzed by pH and Brunauer-Emett-Teller (BET) measurement, and potential side products measured by HPLC-UV. High catalyst activity with near-quantitative DFF yield (> 99.9 %) was achieved in toluene under moderate reaction conditions (90 °C, 0.2 MPa O 2 ). Various Al 2 O 3 supports were screened for optimal catalyst activity and selectivity for DFF, and the most effective was chosen for a Design of Experiments (DoE). With a central composite design based on a response-surface model, the effects of reaction parameters (i. e., catalyst amount, oxygen pressure and temperature) on the reaction rate were investigated, and the selected model tested by analysis of variance (ANOVA). The modeling showed that catalyst amount had the highest relative impact on the reaction rate, and afforded in-depth knowledge about the chemical space investigated.

2,5-diformylfuran (DFF) is a promising green platform chemical obtainable by selective oxidation of 5-(hydroxymethyl)furfural (HMF). In this work, high-purity DFF was synthesized from HMF and compared to formaldehyde (F) in terms of suitability for polymerization in aqueous solution with various phenolic model substances that may be obtainable by depolymerization of lignin. Resorcinol, catechol, and phloroglucinol formed stable hydrogels with DFF, which were converted to alcogels and subsequently dried by extraction with supercritical carbon dioxide. Thermogravimetric analysis and scanning electron microscopy of the resulting aerogels showed no significant differences between DFF and F gels. The high porosity of the aerogels was confirmed by liquid nitrogen BET surface measurement; the specific surface areas measured varied significantly, ranging from 20 to 700 m 2 g −1 .

In this work, resol based binders were prepared with lignin, resorcinol and the bio-based aldehydic platform chemicals 5hydroxymethylfurfural (HMF) and 2,5-diformylfuran (DFF). In preliminary studies, the solubility and stability of DFF in aqueousalkaline conditions was investigated. Various binders were prepared to investigate the influence of the HMF-DFF ratio and the influence of the aldehyde concentration on the molar mass, rheological properties and curing characteristics of the final binders. It is shown that significantly higher molecular weights and viscosities are obtained by using DFF instead of HMF. The properties of the final binder could also be affected by the precise choice of DFF concentration, as this resulted in higher levels of crosslinking. This work offers a novel type of fully bio-based binder that consists of non-toxic components and is therefore less hazardous than some conventional binders.