## 3 Results and Discussion
Figure 5: ID time photographs of the mixture hypergolic chemicals with [TMH]+[CN]- and HOCH2 CH2 NHNH2 using H2O2. Table 2 shows the physical and chemical properties of the mixture of hypergolic chemicals with [EMT]\({}^{+}\)[X]\({}^{-}\) (X = CN\({}^{-}\), N\({}_{3}\)\({}^{-}\), NO\({}_{3}\)\({}^{-}\), NO\({}_{2}\)\({}^{-}\), ClO\({}_{4}\)\({}^{-}\), AlCl\({}_{4}\)\({}^{-}\)) and HOCH\({}_{2}\)CH\({}_{2}\)NHNH\({}_{2}\). The mixture has a very high decomposition temperature (T\({}_{d}\)) above 117 \({}^{\circ}\) C and minus (\(-\)) decomposition energy (\(\Delta\)H\({}_{d}\)). This means that the synthesized hypergolic chemicals with [EMT]\({}^{+}\)[X]\({}^{-}\) and HOCH\({}_{2}\)CH\({}_{2}\)NHNH\({}_{2}\) have very good thermal stability. The density (g/cm\({}^{3}\)) and viscosity (cP) of the mixture was in the range of 1.15\(\sim\)1.25 and 115\(\sim\)938, respectively. We also determined the ID times using a high-speed camera for the reaction between the synthesized hypergolic chemicals and H\({}_{2}\)O\({}_{2}\) as oxidizer. The ID times of [EMT]\({}^{+}\)[N\({}_{3}\)]\({}^{-}\), [EMT]\({}^{+}\)[CN]\({}^{-}\), [EMT]\({}^{+}\)[AlCl\({}_{4}\)]\({}^{-}\), and [EMT]\({}^{+}\)[I]\({}^{-}\) were 18.0, 32.6, 27.6, and 7.97 milliseconds (ms), respectively. This result indicated that the mixture hypergolic chemicals could be used as rocket propellant liquid fuel. The other mixture could be applied as a rocket propellant liquid fuel based on the ID time test. Figure 6: ID time photographs of the mixture hypergolic chemicals with [TMH]\({}^{+}\)[I]\({}^{-}\) and HOCH\({}_{2}\)CH\({}_{2}\)NHNH\({}_{2}\) using H\({}_{2}\)O\({}_{2}\). Figure 7: FT-IR spectrum of explosion gas of an mixture hypergolic chemicals with [TMH]\({}^{+}\)[CN]\({}^{-}\) and HOCH\({}_{2}\)CH\({}_{2}\)NHNH\({}_{2}\) using H\({}_{2}\)O\({}_{2}\). Figures 8-10 show the ID time photographs of the mixture with [EMT]+[N3]-, [EMT]+[CN]- and [EMT]+[I]-, and HOCH2 CH2 NHNH2, respectively, using H2O2 as oxidizer. The ID time of the mixture was determined as 18.0, 32.6, and 7.97 milliseconds, respectively. As a result, the mixture with [EMT]+[X]- (X = N3-, CN-, and I-) could be used as a rocket propellant liquid fuel based on the ignition delay time. \begin{table}
\begin{tabular}{c c c c c c c} \hline
**Cation** & **Anion** & \(\mathbf{T_{d}}\)\({}^{\mathbf{b}}\)**(\({}^{\mathbf{c}}\)C)** & \(\mathbf{d}\)\({}^{\mathbf{c}}\)**(g/cm\({}^{3}\))** & \(\Delta\mathbf{H_{d}}\)\({}^{\mathbf{d}}\)**(kJ/mol)** & \(\mathbf{n}\)\({}^{\mathbf{c}}\)**(cP)** & **ID \({}^{\mathbf{f}}\)**(ms)** \\ \hline \multirow{6}{*}{C\({}_{5}\)H\({}_{10}\)N\({}_{3}\)\({}^{+}\)} & N\({}_{3}\)\({}^{-}\) & 121 & 1.15 & \(-\)36.5 & 201 & 18.0 \\  & CN\({}^{-}\) & 175 & 1.19 & \(-\)37.8 & 250 & 32.6 \\  & NO\({}_{2}\)\({}^{-}\) & 119 & 1.29 & \(-\)53.2 & 248 & 489.0 \\ \multirow{2}{*}{C\({}_{5}\)H\({}_{10}\)N\({}_{3}\)\({}^{+}\)} & NO\({}_{3}\)\({}^{-}\) & 117 & 1.11 & \(-\)22.2 & 115 & 426.0 \\  & ClO\({}_{4}\)\({}^{-}\) & 207 & 1.21 & \(-\)105.3 & 165 & 524.0 \\ \multirow{2}{*}{C\({}_{5}\)H\({}_{10}\)N\({}_{3}\)\({}^{-}\)} & AlCl\({}_{4}\)\({}^{-}\) & 232 & 1.21 & \(-\)32.9 & 191 & 27.6 \\  & \(\Gamma\) & 136 & 1.22 & \(-\)82.4 & 938 & 7.97 \\ \hline \end{tabular}  
* 1-Ethyl-4-methyl-1,2,4-triazolium salts (0.3 mL) were dissolved in 2-hydroxyethylhydrazine (0.7 mL);
* \(\mathrm{T_{d}}\) was measured by DSC; \({}^{\mathbf{c}}\) Density (at 25 \({}^{\mathbf{c}}\)C); \({}^{d}\) AH\({}_{4}\) was obtained from DSC; \({}^{\mathbf{c}}\) Viscosity (at 27.7 \({}^{\mathbf{c}}\)C);
* \(\mathrm{T_{Ignition}}\) delay time was determined by detonation with H2O2.  
\end{table} 
Table 2: Physical and chemical properties of the synthesized 1-ethyl-4-methyl-1,2,4-triazolium salts dissolved at 2-hydroxyethylhydrazine \({}^{\mathbf{a}}\). Figure 8: ID time photographs of the mixture hypergolic chemicals with [EMT]+[N3]- and HOCH2 CH2 NHNH2 using H2O2. Figure 9: ID time photographs of the mixture hypergolic chemicals with [EMT]+[CN]- and HOCH2 CH2 NHNH2 using H2O2.