3,4-二氨基乙二肟(DAG)的制备、晶体结构及热行为

Preparation,Crystal Structure and Thermal Behavior of Diaminoglyoxime

通过乙二醛、盐酸羟胺在NaOH溶液中脱水反应，制备了3，4-二氨基乙二肟（DAG），并培养出DAG的单晶。利用X射线单晶衍射分析、元素分析和傅里叶变换红外光谱分析对其进行结构表征。测试结果表明：晶体属单斜晶系，空间群P21，晶胞参数：a=0．6763（8）nm，b=0．3578（4）nm，c=0．9658（12）nm，β=90．78（2）°，V=0．2338（5）nm^3，Z=2，Dc=1．678g·cm^-3，F（000）=124，μ（MoKα）=0．146mm^-1，最终R因子[I〉2σ（I）]：R1=0．0403，wR2=0．1098，R因子（全部所有数据）：R1=0．0422，wR2=0．1122。DAG分子呈平面构型，为反式结构，其晶体为黄色针状晶体，分子间存在三种氢键，形成三维空间网状结构，提高了分子的稳定性。用TG-DTG和DSC技术研究了DAG的热分解过程，在10℃·min^-1的升温条件下，其熔点为203．5℃，在209～212℃、212～240℃之间发生两步剧烈分解反应，至240℃完全分解。

Diaminoglyoxime （DAG） was prepared by adding glyoxal and hydroxylamine hydrochloride into a cooled solution of sodium hydroxide in water, and the single crystal of DAG was cultured by dehydration at high pressure. The crystal was characterized by using X-ray single crystal diffraction,elemental analysis and FT-IR measurement. The crystal is monoclinic, space group P2j with cell parameters： a=0.6763（8）nm,b=0.3578（4）nm,c=0.9658（12）nm,β=90.78（2）°,V=0.2338（5）nm^3,Z=2,Dc=1.678g·cm^-3,F（000）=124,μ（MoKα）=0.146mm^-1, final R indices [I〉2σ（I）]：R1=0.0403,wR2=0.1098; R indices （all data） R1= 0.0422, wR2 = 0. 1122. The obtained results indicate that DAG is a kind of planar symmetric molecules, and its crystal is acicular crystal. The thermal decomposition process of DAG was predicted by TG-DTG and DSC techniques with a heating rate of I0 ~C ~ rain-j. The measure results show that DAG melting at 203.5 ℃, has two steps of intense thermolysis between 209 -212 ℃ and 212 -240 ℃, and decompose completely up to 240 ℃.