## 3 Results and Discussion
After that we measured the physical and chemical properties of the mixture of hypergolic chemicals with [TMH]\({}^{+}\)[X]\({}^{-}\) and 2-hydroxyethylhydrazine. Table 1 shows the physical and chemical properties of the mixture. The mixture has a very high decomposition temperature (T\({}_{d}\)) above 184 \({}^{\circ}\)C and minus (\(-\)) decomposition energy (\(\Delta\)H\({}_{d}\)). This means that the synthesized hypergolic chemicals with [TMH]\({}^{+}\)[X]\({}^{-}\) and HOCH\({}_{2}\)CH\({}_{2}\)NHNH\({}_{2}\) have very good thermal stability. Figure 2: \({}^{1}\)H-NMR (**a**) and FT-IR spectrum (**b**) of the synthesized \(N\),\(N\),\(N\)-trimethylhydrazinium iodide, [TMH]\({}^{+}\)[I]\({}^{-}\). The density (g/cm\({}^{3}\)) and viscosity (cP) of the mixture was in the range of 1.09-1.15 and 162-216, respectively. Several energetic salts and ILs with considerably reduced ID times have already been designed [14,17,18]. In order to determine their applicability as rocket propellant liquid fuels, we determined the ID times by high-speed-camera for hypergolic chemical reactions between the synthesized hypergolic chemicals and H\({}_{2}\)O\({}_{2}\) as oxidizer. The ID times of [TMH]+[N\({}_{3}\)]- and [TMH]+[CN]- were 55.6 and 97.4 milliseconds (ms), respectively. This result indicates that a mixture of hypergolic chemicals such as [TMH]+[N\({}_{3}\)]- and [TMH]+[CN]- can be used as rock propellant liquid fuels. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Cation** & **Anion** & **T\({}_{\text{d}}\)\({}^{\text{b}}\)(\({}^{\text{c}}\)C)** & **d \({}^{\text{c}}\) (g/cm\({}^{3}\))** & \(\Delta\)H\({}_{\text{d}}\)\({}^{\text{d}}\) (kJ/mol) & **\(\eta\)\({}^{\text{c}}\)(cP)** & **ID \({}^{\text{f}}\)(ms)** \\ \hline \multirow{6}{*}{C\({}_{3}\)H\({}_{11}\)N\({}_{2}\)\({}^{\text{+}}\)} & N\({}_{3}\)\({}^{\text{-}}\) & 198.8 & 1.10 & \(-\)18.31 & 216 & 55.6 \\  & CN\({}^{\text{-}}\) & 192.0 & 1.09 & \(-\)50.65 & 220 & 97.4 \\  & NO\({}_{2}\)\({}^{\text{-}}\) & 190.7 & 1.13 & \(-\)41.19 & 243 & 175.0 \\  & NO\({}_{3}\)\({}^{\text{-}}\) & 195.2 & 1.15 & \(-\)46.63 & 185 & 497.2 \\  & CIO\({}_{4}\)\({}^{\text{-}}\) & 191.0 & 1.13 & \(-\)37.63 & 176 & 970.2 \\  & AICI\({}^{\text{-}}\) & 184.3 & 1.14 & \(-\)80.06 & 162 & 341.0 \\  & \(\Gamma\) & 194.2 & 1.09 & \(-\)64.52 & 203 & 190.3 \\ \hline \end{tabular}  
* \(N\),\(N\),\(N\)-Trimethylhydrazinium salts (0.15 g) were dissolved in 2-hydroxyethylhydrazine (0.85 mL); \({}^{\text{b}}\) T\({}_{\text{d}}\) was measured by DSC; \({}^{\text{c}}\) Density (at 25 \({}^{\text{c}}\)C); \({}^{\text{d}}\) AH\({}_{\text{d}}\) was obtained from DSC; \({}^{\text{e}}\) Viscosity (at 27.7 \({}^{\text{o}}\)C); \({}^{\text{f}}\) Ignition delay time was detonated with H\({}_{2}\)O\({}_{2}\).  
\end{table} 
Table 1: Physical and chemical properties of the mixture solution with \(N\),\(N\)-trimethylhydrazinium salts and 2-hydroxyethylhydrazine \({}^{\text{a}}\). Figures 4-6 show the ID time photographs of the mixture of hypergolic chemicals with [TMH]+[N3]-, [TMH]+[CN]- and [TMH]+[I]- and HOCH2 CH2 NHNH2, respectively, using H2O2 as oxidizer. The ID times of mixtures with [TMH]+[N3]-, [TMH]+[CN]- and [TMH]+[I]- and HOCH2 CH2 NHNH2 was determined as 55.6, 97.4, and 109.3 milliseconds, respectively. As a result it is shown that the mixture of hypergolic chemicals with [TMH]+[N3]- could be used as rocket propellant liquid fuel. In order to determine the presence of toxic chemicals, we measured the FT-IR spectrum of the explosion gas after ignition of the hypergolic chemicals with [TMH]+[CN]- HOCH2 CH2 NHNH2 using H2O2 as oxidizer and this showed the FT-IR spectrum in Figure 7. The characteristic peaks at 1111, 2230, around 3000, and around 3600 cm- due to the NN stretch of hydrazine, CO2 stretch, NH2, and NH stretch appeared. However, we could not observe the characteristic peaks of a nitro group in this experiment. Figure 4: ID time photographs of the mixture hypergolic chemicals with [TMH]+[N3]- and HOCH2 NHNH2 using H2O2.