Synthesis And Characterization Of New Ketazine Compounds

Ketazine compounds have special nitrogen-containing conjugated structure（C=N-N=C）,high reactivity,side chain group structure can be designed,and various stereochemical properties,which have great application value in chemical synthesis,biomedicine,new materials and fuels.According to the needs of the development and preparation of high energy tension ring hydrocarbon fuel,new type of alkyl ketazine compounds was designed and synthesized.The main research contents are as follow:（1）Seven alkyl ketazine compounds were synthesized and their structures were characterized.Isopropyl methyl ketazine(C₁₀N₂H₂₀),2-pentyl ketazine(C₁₀N₂H₂₀),isobutyl methyl ketazine(C₁₂N₂H₂₄),tert-butyl methyl ketazine(C₁₂N₂H₂₄),2-hexyl ketazine(C₁₂N₂H₂₄),cyclopentyl methyl ketazine(C₁₄N₂H₂₄),cyclohexyl methyl ketazine(C₁₆N₂H₂₈)were prepared by hydrazine hydrate method.The structure and purity of the product were determined by ¹H NMR,¹³C NMR,IR,EA and ESI.（2）The configuration,single point energy,infrared vibration frequency and molecular thermodynamic properties of seven obtained ketazine compounds were calculated by Gaussian 09.The results show that there are three configurations of ketazine compounds:（1Z,2Z）,（1Z,2E）,（1E,2E）,in which the single point energy of structure（1E,2E）is the lowest,which is the optimal configuration.In addition,the larger the single point energy difference between different structures,the higher the ratio of the structure（1E,2E）in the mixture.The results of simulated infrared are in accordance with the experimental data,which verify the correctness of the structure.The thermodynamic data show that the reaction is a spontaneous exothermic process withΔH<0 andΔG<0.（3）The synthesis process and physical and chemical properties of cyclopentyl methyl ketazine were studied.The optimized reaction conditions are as follow:the molar ratio of ketone to hydrazine was 2.2:1,the reaction temperature was 100℃,the reaction time was 8 hours,and the reaction solvent was ethanol;the basic physical properties of cyclopentyl methyl ketazine were determined,including boiling point（Tb,236.8℃）,melting point（T_m,-38.2℃）,density(ρ,0.910～0.969 g·cm^-3),dynamic viscosity（η,2.35～13.17 mPa·s）,specific heat capacity(C_p,2.97～3.63 J·g^-1·℃^-1),and the coefficient of thermal expansion(α,8.26×10^-4～8.75×10^-4K^-1)is calculated according to the density.Through the data fitting curve ofρ,η,C_p,αand temperature,it can be seen thatρ,ηdecrease with the increase of temperature,C_p,αincrease with the increase of temperature;the reaction heat of synthesis process of cyclopentyl methyl ketazine is measured by the reaction calorimetry experiment,and the result is as follow:ΔH≈Q_p=-44.91 k J·mol^-1,which is consistent with the theoretical calculation results.In conclusion,under the guidance of molecular energy and the difficulty degree of cyclization,seven unreported alkyl ketazine compounds have been synthesized in this paper.The molecular structure was studied,and the most stable configuration and the possibility of cyclization were confirmed.Among them,cyclopentyl methyl ketazine has outstanding physical and chemical properties,and the synthesis route is simple and feasible,which provides a good raw material for the subsequent study on the preparation of tension ring fuel.