Study On The Optimization Of Synthesis Oxadiazoles Compounds

Oxadiazoles are a type of nitrogen and oxygen heterocyclic compounds with biological activity. oxadiazoles are the most widely studied electron transport materials and energetic materials because of their electron deficiency, high photoluminescence quantum yield, good oxygen balances, and good thermal and chemical stabilities. There has been a growing interest in 3-nitro-5-guanidino-1,2,4-oxadiazole（NOG） and its derivatives with excellent performances. But NOG synthesis process is complex, and the yield is 6%. This can’t satisfy the need of the further research. The main contents are as follows:1. Diaminoglycoluril（AG） has been synthesized using oxidizing uric acid（UA） and sodium persulfate（Na₂S₂O₈） as the raw material. The effect of three important factors which affect the yield of AG are the reaction temperature, the dosage of ammonia water, and n（UA）:n（Na₂S₂O₈）. Based on single-factor experiments, orthogonal experimental were carried out. The most superior experiment conditions were determined to be: a reaction temperature of-5 ℃, c（NH3H2O）=7.4 mol L-1, and a reaction ratio n（UA）-n（Na₂S₂O₈） of 1:4. The favorable yield was 80.86% under optimum reaction conditions.2. NOG has been synthesized using oxidizing AG and acetone peroxide（DMDO） as the raw material. The effect of four important factors which affect the yield of NOG are the reaction temperature, reaction time, the dosage of NH₃-NH₄ Cl, and n（AG）:n（Oxone）. Based on single-factor experiments, orthogonal experimental were carried out. The most superior experiment conditions were determined to be: a reaction temperature of-5 ℃, reaction time of 4h, V（NH₃-NH₄Cl）=280 m L, and a reaction ratio n（AG）:n（Oxone） of 1:14. The favorable yield was 77.78% under optimum reaction conditions.3. A novel compound 3-nitro-5-guanidino-1,2,4-oxadiazole chloride NOGC had been synthesized via NOG as raw material reacting with chloric acid. The single crystal of NOGC was obtained via the normal temperature solvent evaporation method. The crystal structure of NOGC was characterized by X-ray crystal diffraction. The salt of NOGC has formation of robust hydrogen-bonded dimensional networks. Its crystal in the orthorhombic system, space group P2（1）/n4. The three kinds of compounds had been characterized by the elemental analysis, FT-IR and scanning electron microscope. The thermal decomposition perforamnce had been studied by DSC. The nonisothermal decomposition reaction kinetics of the first exothermic process of AG and NOGC had been studied. And the corresponding kinetic parameters had been obtained. The arrhenius equations were worked out.5. DFT-B3 LYP method,with the basis set 6-311 G,was employed to calculate the molecular geometric and electronic structures of AG and NOG.