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91.
[Mo_2FeS_8O_2][Et_4N]_3·CH_3CN晶体属三斜晶系,PI空间群.α=9.998(1)A,b=13.868(3)A,c=16.796(3)A,α=74.66(2)°,β=85.41(1)°,ν=72.21(1)°,Ζ=2.结构参数经块矩阵最小二乘法精修后,最后的偏离因子R=0.037,R_w=0.034.平均键长Mo—Fe为2.722A,Mo—S为2.358A,Fe—S为2.244A,Mo—O为1.697A.结果表明:标题化合物是一个结构新颖的原子簇化合物.它是由一个三价原子簇阴离子与三个一价的乙基季铵阳离子靠静电引力结合在一起,又溶剂合一个乙氰分子的原子簇化合物而形成. 相似文献
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Fe (III) and PAN form the complex Fe(PAN)2OH which can be extracted into CHCl3. The CHCl3 extract shows absorption maxima at 550 nm and 775 nm (log E550 = 4.06, log e775 = 4.08). In the Fe(III)--PAN--Triton X-100 system, two complex species (Fe(PAN)2)+ and/or Fe(PAN)2OH may be formed. (Fe(PAN)2)+ exhibits a stronger absorption peak at 550 nm (log E550 =4.36). In this paper the effect of Triton X-100 micelles on the Fe(III)-PAN reaction has been investigated in detail. We consider that the presence of high density of ethereal oxygen chains in Triton X-100 micelles enables to concentrate hydrated Fe(III) ions and change their existing state. Moreover, the micelles not only increase the reactivity of Fe(III), but also enhance the rate of the color reaction. 相似文献
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对-硝基苯甲酸甲酯(1), 对-硝基苯甲酸正丁酯(2), 对-硝基苯甲酸叔丁酯(3), 对-硝基苯甲酸苄酯(4), 对-硝基苯甲酸苯酯(5), 对-硝基苯甲酸(对-硝基)苯酯(6), 间-硝基苯甲酸甲酯(7), 间-硝基苯甲酸乙酯(8), 间-硝基苯甲酸苯酯(9)和3,5-二硝基苯甲酸甲酯(10)与氢氧化钾在二甲亚砜中反应, 反应产物分别为相应的对-硝基苯甲酸和间-硝基苯甲酸。反应液用ESR检测, 得到1-10自由基负离子的ESR谱。用自旋捕获技术证明反应过程中有OH自由基生成, 自由基捕获剂亚硝基叔丁烷(TNB), 苯基叔丁基硝酮(PBN)和氧气使产物硝基苯甲酸的产率降低, 结果表明, 1-10与KOH与DMSO中反应存在单电子转移机理。 相似文献
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4,5-二溴苯基荧光酮与金属离子的显色反应及混合表面活性剂的作用机理 总被引:3,自引:0,他引:3
本文研究了在表面活性剂(Sf)存在下, 4,5-二溴苯基荧光酮(简称diBr-PF)与12个金属离子(Me)的显色反应。结果表明, diBr-PF是Me的一个高灵敏显色剂。用Huckel分子轨道法(HMO)计算了diBr-PF的π电子密度, 判断了diBr-PF各级H^+的离解顺序及其和Me的配合位置; 测定了在不同Sf存在下, diBr-PF的各级酸离解常数(PKa)及绘制了它的分布曲线; 并研究了阳离子型(C-Sf)-非离子型(n-Sf)混合Sf对Me-diBr-PF显色反应体系的作用机理。 相似文献
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甲基酮与丙烯腈反应可以得到一氰乙基、二氰乙基或多氰乙基化产物。据文献报道,丙酮与丙烯腈反应可以得到少量的4-乙酰基庚二腈,产率约为3.7%,其他4-酰基庚二腈的合成方法还未见报道。我们发现由β-二酮的氰乙基化反应得到的β-二酮二氰乙基化产物1a~c,在碳酸钠水溶液中酮解可以得到4-酰基庚二腈2a~c,产率为59~82%。如果1a~c在氢氧化钾水溶液中水解,则得4-酰基庚二酸3a~c。2a~c与2,4-二硝基苯肼反应得到了相应的苯腙4a~c,2a~c经KOH水解亦得3a~c。 相似文献
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1,2-二氯四甲基硅锗烷分别与环戊二烯基锂及四甲基环戊二烯基锂反应得到两个新的双齿配体:C5H5Me2SiGeMe2C5H5(9)和C5HMe4Me2SiGeMe2C5HMe4(10).配体9和10分别与Fe(CO)5在二甲苯中加热生成四甲基硅锗桥连双环戊二烯基四羰基二铁(11)和四甲基硅锗桥连双(四甲基环戊二烯基)四羰基二铁(13).11和13均可发生热重排反应,生成[(η^5-C5R4)Fe(CO)2]2(μ-Me2Si)(μ-Me2Ge)(R=H,12;R=Me,14)。测定了化合物11,12,13及14的晶体结构,讨论了桥连四甲基环戊二烯基配体的位阻效应对其某些结构参数以及重排反应性的影响。 相似文献
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《Composite Interfaces》2013,20(5-7):689-703
The effect of the Mg(OH)2 particle size on the thermal degradation and flammability of a model nanocomposite is presented. In order to investigate the effect of particle size on the flammability and thermal stability of materials intended for cable coatings, the ethylene–vinyl acetate copolymer (EVA) was filled with two types of magnesium hydroxide (Mg(OH)2) with the average particle size 20 nm and 2000 nm. The thermogravimetric experiments performed under nitrogen and air atmosphere did not reveal any substantial effect of particle size on the mechanisms and kinetics of Mg(OH)2 decomposition. Both types of Mg(OH)2, at temperatures above 350°C, decomposed endothermally to MgO and H2O. At the same filler volume fraction, composites with the larger Mg(OH)2 particles exhibited greater value of the limiting oxygen index (LOI) compared to Mg(OH)2 nanocomposites. It is proposed that the reduction of Mg(OH)2 particle size below 200 nm results in the catalytic effect of Mg2+ to become more prominent compared to coarser particles. In the case of nano-sized Mg(OH)2, a large portion of polymer matrix is in direct contact with filler surface due to the high specific surface area of the filler used. Large filler–matrix contact area most probably resulted in the surface-induced catalytic effects of the Mg2+ ion on degradation of polyolefins, already described in the literature, accelerating thermal degradation of EVA matrix. This process acts against the flame retarding effect of the Mg(OH)2 thermal decomposition. Furthermore, larger filler surface of nano-filler led to the indispensable change of the deformation response of EVA compared to the micro-filled composite. 相似文献