Cellulose treatment dissolution/precipitation in inorganic salt hydrates produces a dramatic morphology change that yields a reactivity improvement respect the untreated for transformations.

We propose the treatment of barley straw with 1-ethyl-3-methylimidazolium acetate [EMIMAcO] ionic liquids (ILs) and subsequent precipitation with antisolvent mixtures, thus allowing the separation of the sugar-rich fractions (cellulose and hemicellulose) from the lignin fraction. For this purpose, different concentration ranges of acetone:water antisolvent mixtures were studied. In all cases, a high recovery percentage and a high and effective separation of fractions was achieved for 1:1 acetone:water. The fractionated lignocellulosic compounds were studied by using infrared spectroscopy, scanning electron microscopy and ¹H nuclear magnetic resonance characterization techniques. This method allows the possibility of reusing IL, confirming the versatility of the established method. The fraction rich in cellulose and hemicellulose was subjected to acid hydrolysis (0.2 mol/L H₂SO₄) for 5 h at 140 °C, obtaining a yield of total reducing sugars of approximately 80%, much higher than those obtained in non-pretreated samples.

High catalytic activity is found to be due to the combination of a chromium catalyst with large pores (MIL-101(Cr)) with aprotic solvents (γ-valerolactone−10% H ₂ O).

Lignocellulosic residues from energy crops offer a high potential to recover bioproducts and biofuels that can be used as raw matter for agriculture activities within a circular economy framework. Anaerobic digestion (AD) is a well-stablished driver to convert these residues into energy and bioproducts. However, AD of lignocellulosic matter is slow and yields low methane potential, and therefore several pre-treatment methods have been proposed to increase the energy yield of this process. Hereby, we have assessed the pre-treatment of lignocellulosic biomass (barley straw) with the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate and its effect on the biochemical methane potential (BMP). The BMP of the residue was evaluated at different inoculum to substrate (I/S) ratios and working under meso and thermophilic conditions. Solids destruction upon AD is highly enhanced by the IL-pretreatment. This also resulted in a higher BMP, both in mesophilic as well as thermophilic conditions. At the optimum I/S ratio of 2:1 (dried weight, dw), the BMP of the IL-pre-treated feedstock increased 28 and 80% for 35 days of thermophilic and mesophilic AD, respectively, as compared to the fresh feedstock, achieving values of 364 and 412 LCH4/kgTS. We also explored the effect of this pretreatment on the phosphorus recovery potential from the digestate upon release from the AD process. Thermophilic anaerobic digestion of IL-pre-treated biomass provided the highest P recovery potential from lignocellulosic residues (close to 100% of the theoretical P content of the lignocellulosic feedstock). Therefore, the pretreatment of lignocellulosic feedstock with IL before AD is a promising platform to obtain bioenergy and recover P to be regained for the agriculture sector.

The direct conversion reaction of glucose to 5‐hydroxymethylfurfural (HMF) is studied using metal organic framework (MOF) as Lewis‐acid catalysts and a polyoxometalate (POM), silicotungstic acid, as a Brønsted‐type acid with a mixture of 1% glucose solution in γ‐valerolactone (GVL)‐10% H₂O at 140 °C. The study is carried out with two routes: one using MOF and POM tandem catalysts added independently and the other through the synthesis of a composite material denoted POM@MOF. The activity tests show that the profiles of the conversion and yield of HMF achieved in both routes are similar, with the reactions with MIL‐53(Al) and MIL‐101(Cr) catalysts producing the highest yield of HMF (40% after 8 h of reaction). Stability tests are performed on the POM@MOF catalysts based on MIL‐53(Al) and MIL‐101(Cr). MIL‐53(Al) and HSiW@MIL‐101(Cr) can be reused, showing a progressive loss in HMF yield due to the leaching of POM.