## 2 Materials and Methods  
**Materials and Chemicals. ** All chemicals were acquired from Merck, excluding xylan (from beechwood) and lignin (alkaline), which were acquired from TCI-Europe; zinc chloride anhydrous (98+%) acquired from Alfa Aesar; acetone (synthesis grade) and sulfuric acid (1 M), acquired from Scharlab; hydrochloric acid (37%, pure pharma grade) acquired from AppliChem Panacea; and sulfuric acid (0.01 N), acquired from VWR. LB (barley straw, pruning waste, and vine shoot) was used as well as the compositional analysis was provided by the BIOCAR Unit of CIEMAT. **Analysis of lignocellulosic biomass**. Lignocellulosic biomasses were analyzed by standard methods adapted for biomass analysis from the National Renewable Energy Laboratory (NREL; Denver, CO, USA) [34]. The data obtained on a dry basis are shown in Table 1.  
**Treatment of lignocellulosic biomass. ** The scheme of the dissolution process of LB using inorganic salt hydrate as a solvent is shown in Figure 1. A total of 8 g of lignocellulosic biomass was placed on slowly into 224.2 g of ZnCl\({}_{2}\cdot\)4H\({}_{2}\)O at the selected temperature in a flask equipped with magnetic stirring, this proportion was selected on the basis of previous works where the dissolution of cellulose was fast and very efficient [10; 35; 36]. After dissolution, the mixture was centrifuged, and a dark viscous liquid was separated from a black solid: \begin{table}
\begin{tabular}{c c c c} \hline  & **Barley Straw** & **Pruning Waste** & **Vine Shoots** \\ \hline
**Extractives** & **13.37 \(\pm\) 0.10** & **9.30 \(\pm\) 0.60** & **8.3 \(\pm\) 0.2** \\ Aqueous & 10.99 \(\pm\) 0.31 & 6.90 \(\pm\) 0.60 & 7.14 \(\pm\) 0.4 \\ Organic & 2.38 \(\pm\) 0.26 & 2.40 \(\pm\) 0.25 & 1.16 \(\pm\) 0.25 \\
**Cellulose** & **31.09 \(\pm\) 1.25** & **37.80 \(\pm\) 1.40** & **32.50 \(\pm\) 0.5** \\
**Hemicellulose** & **27.23 \(\pm\) 0.44** & **14.0 \(\pm\) 0.1** & **18.40 \(\pm\) 0.3** \\ Xylan & 22.06 \(\pm\) 0.47 & 9.6 \(\pm\) 0.1 & 16.70 \(\pm\) 0.3 \\ Galactan & 1.30 \(\pm\) 0.01 & 2.20 \(\pm\) 0.12 & 2.10 \(\pm\) 0.07 \\ Arabiman and & 3.87 \(\pm\) 0.03 & 1.30 \(\pm\) 0.02 & 1.93 \(\pm\) 0.03 \\ Mannan & 1.72 \(\pm\) 0.02 & 4.7 \(\pm\) 0.1 & 5.30 \(\pm\) 0.05 \\
**Insoluble Lignin** & **16.67 \(\pm\) 1.13** & **25.4 \(\pm\) 1.2** & **25.4 \(\pm\) 0.1** \\
**Soluble Lignin** & **2.10 \(\pm\) 0.03** & **3.7 \(\pm\) 0.2** & **1.60 \(\pm\) 0.05** \\
**Ash** & **3.89 \(\pm\) 0.05** & **3.7 \(\pm\) 0.1** & **3.60 \(\pm\) 0.3** \\ \hline \end{tabular}
\end{table} 
Table 1: Composition results (wt.%) of the different lignocellulosic biomasses dried at 105 \({}^{\circ}\)C.  
1. The black solid obtained (Solid I) was washed with 5 \(\times\) 20 mL of 0.1 N HCl and 5 \(\times\) 20 mL of distilled water to eliminate residues of inorganic salt hydrate [18] or until the color of the solution became transparent. 2. The dark viscous liquid obtained in the centrifugation was mixed with twice the water weight of the liquid, and then precipitation occurred. The solid, labeled Solid II, was filtered, and the mother liquor, which contain the dissolved hemicellulose, was separated. Solid II was isolated and washed with 5 \(\times\) 20 mL of 0.1 N HCl and 5 \(\times\) 20 mL of distilled water to remove the inorganic salt hydrate traces. Once the solution became clear, the solid was washed with acetone, and the clean solid was labeled Solid II. 3. The dark acetone solution [10; 17; 37] was recovered, and a solid was recovered by solvent evaporation in a rotary evaporator (Solid III). **Hydrolysis. ** Hydrolysis reactions were carried out in a thermostatic Teflon-lined steel stirred reactor equipped with a stirred magnet and a pressure addition funnel (BR-100, Berghof Intruments) [14; 16; 38]. A total of 0.5 g of material was added to the reactor with 40 mL of water and heated to 140 \({}^{\circ}\)C. Subsequently, 10 mL of H\({}_{2}\)SO\({}_{4}\) (0.2 M) was added and from this moment, the \"reaction time\" was measured.