一个新的过氧钼酸盐(NH_4)_4(CH_6N_3)_2[Mo_7O_(23)(O_2)]·3H_2O的合成、晶体结构及催化性质

Synthesis,Crystal Structure and Catalytic Properties of the New Peroxy Molybdate (NH_4)_4(CH_6N_3)_2[Mo_7O_(23)(O_2)]·3H_2O

以钼酸铵和盐酸胍为原料,30%双氧水为氧化剂,在室温下采用常规的水溶液法合成了一种新的单过氧七核钼酸盐(NH4)4(CH6N3)2[Mo7O23(O2)]·3H2O,通过元素分析、X-射线单晶衍射、红外光谱、固体紫外可见光谱对其进行了表征。标题化合物属于单斜晶系,P21/n空间群,a=1.367(14)nm,b=1.085(11)nm,c=2.748(3)nm,β=93.15(2)°,V=4.0685(7)nm3,Z=4,Dc=2.031g·cm-3,R1=0.0713,wR2=0.2199(I>2σ),GOF=1.03。将合成的过氧钼酸盐(NH4)4(CH6N3)2[Mo7O23(O2)]·3H2O作为催化剂用于苯甲醇氧化合成苯甲酸的反应,考察了催化剂用量、氧化剂(30%H2O2)的用量、反应温度、反应时间等对苯甲酸产率的影响。最佳催化反应条件是:n(催化剂)∶n(苯甲醇)=0.063∶1,n(H2O2)∶n(苯甲醇)=40∶1,反应温度85℃,反应时间7 h,苯甲酸的产率达到82.2%。

A new monoperoxoheptamolybdate（ NH4）4（ CH6N3）2[Mo7O23（ O2） ]·3H2O was synthesized by reacting of ammonium molybdate,guanidine hydrochloride and 30% Hydrogen peroxide as the oxidant in aqueous solution at room temperature. It was characterized by elemental analysis,single crystal X-ray diffraction,IR and solid UV-Vis diffuse reflectance spectroscopy. The title compound belongs to monoclinic system with space group P21/ n,a = 1. 367（ 14） nm,b = 1. 085（ 11） nm,c = 2. 748（ 3） nm,β = 93. 15（ 2） °,V = 4. 0685（ 7） nm3,Z = 4,Dc= 2. 031 g·cm- 3,R1= 0. 0713,wR2= 0. 2199（ I 2σ）,GOF = 1. 03. By using the title compound as the catalyst and 30% H2O2 as the oxidant,the effects of catalyst dosage,oxidant dosage,reaction time and reaction temperature etc. on the oxidation of benzyl alcohol to benzoic acid were investigated. The optimal reaction conditions are as follows： n（ catalyst） ∶n（ benzyl alcohol） = 0. 063∶ 1,n（ H2O2） ∶ n（ benzyl alcohol） = 40∶ 1; reaction temperature 85 ℃ andreaction time 7 h,the yield of benzoic acid can reach 82. 2%.