## 3 Results and Discussion
### Performance of [DBDImI]I as a Solvent for Glucose Conversion  
The performance of [DBDImI]I as a solvent in glucose conversion was studied further at optimum conditions. All products of glucose conversion were analyzed using HPLC. High glucose conversion to HMF (82.2%) was observed in the system with [DBDImI]I and 1M H\({}_{2}\)SO\({}_{4}\). A low yield of HMF (5.2%) from glucose was observed in the control system with only glucose and water. The addition of H\({}_{2}\)SO\({}_{4}\) in the control has improved the glucose conversion to HMF, with a yield of 49.1%. The glucose conversion results in [DBDImI]I or water, with or without H\({}_{2}\)SO\({}_{4}\) at optimum conditions, are shown in Table 1.  
The main product in glucose conversion was HMF. However, LA and FA were also formed as side products after the decomposition reaction due to the more reactive glucose in the presence of [DBDImI]I as both solvent and Lewis acid catalyst. According to many reported studies, the acidic catalyst promotes water formation in the glucose dehydration process [7; 11; 20; 26; 47; 48; 49]. [DBDImI]I increased the -OH group's reactivity in glucose (stretch out the -OH bonding) for the easier release of water molecules and produced HMF. The use of [DBDImI]I as a solvent in glucose dehydration increased the HMF production in the acid catalyst due to the synergistic effect between the [DBDImI]I cation of IL and H\({}^{+}\) to make a more selective reaction. Furthermore, [DBDImI]I made an easier separation of HMF and side products from the trace glucose and impurities due to its property as a surfactant. The use of water as a solvent system without a catalyst showed its incapability to produce any products. These results supported the ability of [DBDImI]I to catalyze the glucose dehydration reaction, as well as being the better medium compared to water. The hydrophobicity of [DBDImI]I supported the selectivity of HMF capturing in the biphasic system (aqueous-organic (IL)) after completion of the reaction; thus, the separation of the product became easier. All of the glucose conversion products can be separated easily from IL due to the hydrophilic nature of HMF, LA, and FA. The IL can be recycled in the process. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Solvent**} & \multirow{2}{*}{**Catalyst**} & \multicolumn{4}{c}{**\%Mole Yield of Product**} & \multirow{2}{*}{**Remark**} \\ \cline{3-3} \cline{5-6}  & & & **HMF** & & **Levelinic Acid** & \\ \hline
[DBDImI] & Non & \(52.1\pm 1.0\) & \(9.6\pm 0.3\) & \(1.9\pm 0.1\) & [DBDImI] gives better performance as a \\ H\({}_{\text{O}}\) & Catalyst & \(4.3\pm 0.1\) & \(0.8\pm 0.1\) & \(0.2\pm 0.1\) & solvent \\ \hline
[DBDImI] & H\({}_{2}\)SO\({}_{4}\) & \(82.2\pm 2.1\) & \(14.9\pm 0.4\) & \(2.9\pm 0.1\) & [DBDImI] performance as a solvent \\ H\({}_{\text{O}}\) & H\({}_{2}\)SO\({}_{4}\) & \(49.1\pm 1.4\) & \(8.9\pm 0.4\) & \(1.8\pm 0.1\) & increased with the addition of H\({}_{\text{S}}\)SO\({}_{4}\) \\ \hline \hline \end{tabular}  
* The results are the average of five replications with SD.  
\end{table} 
Table 1: Results of glucose conversion at optimum conditions (100 \({}^{\circ}\)C for 2 h)*. Figure 3: HMF rehydration at 80 \({}^{\circ}\)C to LA (**a**) and FA (**b**) in [DBDImI]I or water, with or without H\({}_{2}\)SO\({}_{4}\). The proposed mechanism of glucose dehydration in [DBDIm]I is shown in Figure 4. In the first step, the pyranose-ring-opening of glucose occurred to form the first intermediate molecule (b). The protonation of the anomeric -OH group within the intermediate molecule (b) by Bronsted acid led to the next intermediate species (c). The I\({}^{-}\) anion of the IL deprotonated the -OH group of the intermediate species (c) to form a furanose ring (d). This intermediate was further oxidized assisted by the [DBDIm]\({}^{+}\) cation to produce the following molecule (e). At the last step, HMF (f) production occurred through the second dehydration supported by [DBDIm]I at 100 \({}^{\circ}\)C. [PERSON] et al.