## 4 Conclusions  
This study underscores the considerable potential of DESs, specifically the (ChCl:ZnCl\({}_{2}\)) DES, for the effective depolymerization of KL. Our results reveal that both reaction temperature and time are crucial for optimizing the yield and quality of the generated bio-oil. Under optimal conditions of 190 \({}^{\circ}\)C and 8 h, the depolymerization process not only increased the liquid product yield but also substantially reduced the molecular weight of the bio-oil, indicating enhanced depolymerization efficiency. Notably, the M\({}_{\rm w}\) value of the bio-oil derived from the DES-assisted depolymerization of KL was 1498 g/mol, which was considerably lower compared to the corresponding value of 1872 g/mol for the bio-oil obtained without the DES treatment. This reduction in molecular weight, coupled with improved homogeneity, highlights the effectiveness of the DES in facilitating lignin breakdown and enhancing product quality. Furthermore, the increase in the HHV of the RL sample from 24.82 MJ kg\({}^{-1}\) to 26.44 MJ kg\({}^{-1}\) demonstrates that the (ChCl:ZnCl\({}_{2}\)) DES-assisted depolymerization treatment not only enhances lignin vaporization but also contributes to the production of sustainable biofuels with higher energy contents. These findings pave the way for further explorations of (ChCl:ZnCl\({}_{2}\)) DESs in biomass conversion processes, emphasizing their potential as cost-effective, non-toxic, and efficient alternatives to traditional solvents. Conceptualization, S.G.; Methodology, S.G.; Software, S.G.; Formal analysis, M.R. ; Investigation, S.G.; Resources, J.-H.P. ; Data curation, M.R. ; Writing--original draft, S.G.; Writing--review and editing, M.R. ; Visualization, M.R. ; Supervision, J.-H.P. ; Project administration, J.-H.P. ; Funding acquisition, J.-H.P. All authors have read and agreed to the published version of the manuscript. Figure 8: Mechanism of ChCl:ZnCl\({}_{2}\) DES-assisted KL depolymerization. * [PERSON] et al. (2010) [PERSON]; [PERSON]; [PERSON]; [PERSON]; [PERSON] Cleaving the \(\beta\)-O-4 Bonds of Lignin Model Compounds in an Acidic Ionic Liquid, 1-H-3-Methylimidazololimoride: An Optional Strategy for the Degradation of Lignin. _ChemSusChem_**2010**, \(3\), 1078-1084. [CrossRef] [PubMed]
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