## 4 Conclusions  
Using inorganic salt hydrate and water as an antisolvent for dissolving biomass can be used to fragment and obtain cellulose, hemicellulose, and lignin. Carrying out dissolution with ZnCl\({}_{2}\).4H\({}_{2}\)O for 24 h at 70 \({}^{\circ}\)C is the appropriate time and temperature to obtain a favorable separation. In this procedure, we obtained three solids: (a) a first solid obtained from direct filtration after the dissolution treatment (Solid I); (b) a solid obtained after precipitation with the antisolvent (water) (Solid II); and (c) a solid obtained by washing Solid II with acetone and evaporating the acetone (Solid III). Characterization by different techniques (FTIR, XRD, SEM, and NMR) and analysis by NREL show that Solid I, the undissolved part of the starting material, is a solid rich in lignin and undissolved cellulose with changes in its structure and its morphology with respect to the original biomass. Solid II is a solid rich in cellulose (<80% in all cases) with a low presence of lignin and hemicellulose, where cellulose type II (FTIR) is present. Finally, Solid III is pure lignin, as shown by the complete loss of crystallinity and morphology in XRD and SEM and the great similarity with the original lignin in FTIR or NMR. An HPLC analysis showed that hemicellulose is mainly dissolved and hydrolyzed in the dissolution treatment, and the amount present in all solids is very small. An acid hydrolysis carried out on Solid I and Solid II demonstrated the effectiveness of the treatment with the inorganic salt hydrate with respect to the original biomass. In all cases, the conversion and glucose yield decreased in the order Solid II > Solid I > untreated biomass. Solid II presented the best results due to the higher concentration of structural carbohydrates; barley straw had a conversion of 91% and a glucose yield of 83%, the pruning waste had a conversion of 94.6% and a glucose yield of 84%, and finally, the vine shoots had a conversion of 95.4% and a glucose yield of 84%. These results are similar, and show an improvement on in all cases, to the data obtained for the solid obtained after treated biomass with ionic liquid [10] with a conversion of 93% and a glucose yield of 52%. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app13052953/s1](https://www.mdpi.com/article/10.3390/app13052953/s1)]([https://www.mdpi.com/article/10.3390/app13052953/s1](https://www.mdpi.com/article/10.3390/app13052953/s1)), Detailed Experimental Methods, Characterization Section, and Figures S1-S12. Experimental work: M.L.-S. and D.M.S. ; supervision: [PERSON]-d. and [PERSON]-M.; writing--original draft preparation: M.L.-S. and S.M.-d; writing--review and editing: J.M.C.-M. All authors have read and agreed to the published version of the manuscript. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample** & **TRS (g/L)** & \begin{tabular}{c} **\% Yield of** \\ **Reducing Sugars** \\ \end{tabular} & \
\begin{tabular}{c} **\% Selectivity of** \\ **Reducing Sugars** \\ \end{tabular} &
\begin{tabular}{c} **Total Monomeric** \\ **Sugars (g/L)** \\ \end{tabular} \\ \hline Barley Straw & 2.9 & 45 & 54 & \(1.8\) \\ B. S. Solid I & 3.6 & 54 & 63 & 1.9 \\ B. S. Solid II & 5.7 & 80 & 88 & 4.6 \\ Pruning Waste & 2.0 & 35 & 46 & 1.4 \\ P.W. Solid I & 3.9 & 64 & 72 & 2.1 \\ P.W. Solid II & 5.4 & 74 & 78 & 4.6 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Results of TRS measurements for the samples obtained after the acid hydrolysis reaction. **Funding:** This research was funded by the Comunidad de Madrid (Spain) and the ERDF (European Regional Development Fund), grant number S2018/EMT-4344 (BIOTRES-CM), and by MCIN/AEI/10.13039/501100011033 and by \"ERDF A way of making Europe\" Grant PID2020-112594 RB-C33. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The data that support the findings of this study are available from the corresponding author on reasonable request.