首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
PM012—xVx和PMo12—xWx杂多酸的XPS研究:Ⅰ....   总被引:1,自引:1,他引:0  
胡刚  于亚莉 《应用化学》1991,8(4):11-15
  相似文献   

2.
3.
张全争  田长安 《化学通报》2011,(10):942-946
采用水热反应合成了有机-无机杂化的Keggin型配合物(C12H9N2)3[PMo12O40],并通过X-射线单晶衍射对其结构进行了分析。该配合物为正交晶系P212121空间群,晶胞参数为a=1.20800(1)nm,b=2.10108(4)nm,c=2.24234(5)nm。配合物包含了孤立的Keggin型[PMo1...  相似文献   

4.
本文用红外光谱研究了Fe-Si-ZSM-12分子筛,观察到其结构单元的骨架振动谱带在545cm~(-1)、580cm~(-1)和630cm~(-1),而表示Si—O—Fe键的对称伸缩振动谱带在660cm~(-1)和780cm~(-1),且随铁含量增加向高波数位移。Fe-Si-ZSM-12分子筛的穆斯堡尔谱的结果表明,骨架铁的IS值很小,IS=0.086(-0.17)mm/s,且QS=0.0mm/s,这明显不同于非骨架铁IS=0.53mm/s。在Fe-Si-ZSM-12分子筛的ESR谱图上,观察到骨架铁的顺磁信号(g=4.3),样品焙烧后顺磁信号减弱,骨架铁向非骨架位迁移。IR、Mossbauer、ESR结果证明,Fe~(3+)进入了骨架。  相似文献   

5.
Bi4PMo(12)O(49)催化剂的性质及其在丙烷选择氧化中的活性   总被引:1,自引:0,他引:1  
从钼磷酸出发制备了Bi4PMo12O49催化剂,IR及XRD分析结果表明,高温焙烧后其基本组成为α-Bi2Mo3O12/MoO3,考察了该催化剂对丙烷的选择氧化生,ESR及XPS测定结果表明,反应后催化剂中Mo^5+的含量明显增加,这暗示着反应物种吸附在Mo^6+上,而Bi则为气相氧的入口。  相似文献   

6.
Xu  Mei-Xian  Lin  Shen  Xu  Li-Min  Zhen  Si-Lin 《Transition Metal Chemistry》2004,29(3):332-335
The title compound H3[PMo12O40]· 3C2H6O was prepared and characterized by X-ray crystallography, its i.r. spectrum, cyclic voltammetry and e.s.r. spectra. The anion of the title compound is a Keggin-type heteropoly structure based upon a central PO4 tetrahedron surrounded by 12 MoO6 octahedra arranged in four groups of three edge-shared octahedra Mo3O13. Weak hydrogen bonds exist between the organic solvent molecules and the heteropoly anion. The catalytic activity of the title compound was determined by the synthesis of butyl acetate. The conversion of n-BuOH reached 93.3% and the yield of MeCO2Bu-n was 92.0% when the ratio of MeCO2H to n-BuOH, catalyst amount, reaction time, reaction temperature were 2:1, 0.24% of the reactants (50 mg), 2.0 h and 115 120 °C, respectively.  相似文献   

7.
ZSM—12沸石的合成   总被引:2,自引:0,他引:2  
在水热体系中以甲基三乙基碘化铵为结构导向剂合成了SiO2/Al2O3=32.2~∞的ZSM-12分子筛,XRD和IR证明它们具有MTW拓扑结构;并以SEM和DTA表征晶体形貌和热稳定性,考察了催化性能。  相似文献   

8.
Two polyoxometalate-templated nickel-Schiff-base compounds, {[Ni(L)2]2[PMo12O40][Cl] · 1.5DMF · H2O} n (1) and {[Ni(L)2]2[PMo12O40][Cl] · DMSO · CH3OH · 0.5H2O} n (2) (where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene), were synthesized in situ from Ni2+ and L in H2O/DMF/CH3OH or H2O/DMSO/CH3OH at room temperature and characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. The results of the single-crystal X-ray diffractions suggested that both compounds have the same packing of the Ni(II)-Schiff-base cation layer and Keggin anion layer. Thermogravimetric analyses suggested that two supramolecular compounds have similar thermal stabilities based on the same packing of the cation and anion layers.  相似文献   

9.
近几年来,静电自组装成膜材料的合成、薄膜的制备、表征和功能研究已得到了迅速发展[1~6],但对成膜材料分子结构与薄膜性质间构效关系的研究报道则较少[6].杂多化合物具有特殊的结构特征和氧化还原性质,而半菁化合物是备受关注的二阶非线性光学和光电转换材料[7,8],二者形成的  相似文献   

10.
芳香醛和脂肪醛在温和条件下经乙酸酐和Cu3/2PMo12O40/SiO2催化可转变成 1,1-二乙酸酯. 发现Cu3/2PMo12O40/SiO2是在无溶剂存在下制备 1,1-二乙酸酯的有效催化剂. 使用同一催化剂和乙腈作溶剂可使生成的 1,1-二乙酸酯发生逆反应脱保护生成醛. 这种新的方法具有反应时间短和收率高的优点,而且催化剂重复使用几次不丧失活性.  相似文献   

11.
A new organometallic-inorganic hybrid compound {[Mn(L)2]2[PMo12O40][NO3] · 4CH3OH · 3H2O} n (I), where L is 1,4-bis(4-imidazolyl)-2,3-diaza-1,3-butadiene) was synthesized in situ from [PMo12O40]3?, Mn2+ and L reaction in an H2O-DMSO-CH3OH mixture at room temperature, and the product was structurally characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray diffraction analysis. Compound I is constructed from alternating layers of the metal-Schiff-base cation and Keggin anions based on electrostatic forces and hydrogen bond interactions.  相似文献   

12.
甲烷部分氧化反应是目前催化研究领域的一个热点^[1,2],杂多酸以其确定的化学组成、特定的酸性和氧化性以及空间笼形结构而成为在分子水平上进行催化剂设计的良好选择^[3]。Kasztelan等^[4]曾利用SiO2负载的磷钨酸作为催化剂研究了CH4的氧化过程。激光促进表面反应(LSSR)技术已成为一种充满应用前景的光催化合成方法^[5,6]。本文以磷钼酸和CaF2负载磷钼酸为固体材料,TEA CO2激光器为光源,按固体表面键激发模式,考察了CH4部分氧化反应性能。  相似文献   

13.
[Co(phen)3]2[PMo12O40](OH)的水热合成及晶体结构   总被引:1,自引:0,他引:1  
利用水热合成法制备了Keggin结构阴离子有机一无机复合物[Co(phen)3]2[PMo12O40](OH),通过元素分析,红外光谱和X射线单晶衍射等对其进行了表征.结果表明,该化合物属于单斜晶系,C2/c空间群.=1.97225(18)nm,b=1.81079(16)nm,c=2.5117(2)nm,β=100.5380(10)°,V=8.819O(14)nm^3,Z=4,R1=0.0587,wR2=0.1211.该化合物分子由一个多阴离子[PMo12O40]^3-,两个[Co(phen)3]^2+及一个羟基组成.  相似文献   

14.
利用固相反应法制备了磷钼酸(H3PMo12O40,简称PMA)掺杂聚苯胺,并以红外光谱(FT-IR)、X-射线衍射(XRD)、循环伏安(cyclic voltamm ogram)等测试方法对聚苯胺进行了表征。结果表明,无论是液相法还是固相法,磷钼酸掺杂于聚苯胺中,仍保持自身结构特征,与传统液相合成的磷钼酸掺杂聚苯胺相比,固相反应法合成的磷钼酸掺杂聚苯胺的晶化率和电活性略差。固相反应法制备的磷钼酸掺杂聚苯胺在对抗坏血酸(AH2)电催化氧化中,表现出比液相合成更好的电催化活性。  相似文献   

15.
 研究了Cu3/2PMo12O40表面改性的骨架镍催化剂上含羰基化合物(正丁醛、异丁醛、丙酮、丁酮和环己酮)及含碳-碳双键化合物(苯、糠醇和1-辛烯)的加氢反应.结果表明,随着骨架镍催化剂上Cu3/2PMo12O40附着量的增加,含羰基化合物的加氢反应速率上升,而含碳-碳双键化合物的加氢反应速率下降.与未改性的骨架镍催化剂相比,当骨架镍催化剂上Cu3/2PMo12O40附着量为6.3%时,羰基的加氢活性提高2倍以上,碳-碳双键的加氢活性下降30%以上.计算了各种化合物在催化剂上的表观活化能.结果表明,Cu3/2PMo12O40表面改性的骨架镍催化剂上,羰基加氢反应的表观活化能降低,而碳-碳双键加氢反应的表现活化能升高.从动力学角度讨论了Cu3/2PMo12O40对骨架镍催化剂的影响.用XPS对骨架镍表面的Cu3/2PMo12O40进行了研究,发现杂多酸盐的Keggin型结构已被破坏,Cu3/2PMo12O40分子中的Cu2+被还原为Cu0,而Mo6+被部分还原为Mo5+和Mo4+;Cu2+和Mo6+价态的变化是由骨架镍表面吸附的活泼氢所引起的.羰基加氢选择性的提高是Cu0和混合价态Mo共同作用的结果.  相似文献   

16.
Two new inorganic-organic hybrid compounds based on α-Keggin clusters and Ag-(1H-Pyrazole) subunits, [AgL2]4[SiMo12O40] (1) and [AgL2]3[PMo12O40] (2) (L = pyrazole), have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. In 1, there are two kinds of chains, the chains linked by two [AgL2]+ clusters and the other linked only by one [AgL2]+, which further connect by sharing [SiMo12O40]4? anions to construct a 2-D layer. In 2, four-supporting [PMo12O40]3? anions are fused by [Ag(1)L2]+ subunits to form a 1-D chain. Through weak interactions of Ag?O (3.091 Å) a 2-D supramolecular layer is constructed. Additionally, the electrochemical properties of title compounds and the photocatalytic properties of 2 have been studied.  相似文献   

17.
Tetra-Schiff base macrocyclic compound containing benzo-12-crown-4 was synthesized via condensation of 2,6-diformyl-4-methyl-phenol with 4′,5′-diaminobenzo-12-C-4 promoted by proton. The compound was characterized by MS,IR ^1HNMR spectroscopy and elemental analysis.  相似文献   

18.
Deposited catalysts composition H3PMo12O40/SiO2 and Ag/H3PMo12O40/SiO2 have been synthesized on the basis of fumed silica, including milling technique. Physical–chemical characteristics of prepared catalysts have been studied by means of XRD, DTA-TG, FTIR, UV–Vis spectroscopy, and adsorption of nitrogen. Catalysts possess meso- or meso-macroporous structure and contain deposited Keggin heteropolycompounds. Deposition of heteropolycompounds on support with high specific surface area results in increase of selectivity to epoxide in epoxidation reactions. The use of milling during catalyst synthesis leads to further growth of selectivity of epoxides formation.  相似文献   

19.
(C16H20N2)3PMo12O40/PVA复合薄膜的制备及其光化学和电化学性质;四甲基联苯胺;钼磷杂多酸;聚乙烯醇;光化学性能;电催化活性  相似文献   

20.
用磷钼酸与咪唑合成一种新的杂多酸-有机电荷转移盐(C3H5N2)3[PMo12O40]。通过元素分析、红外光谱、固体漫反射光谱、电子自旋共振及热分析等测试技术对其进行了表征,用单扫描法(Achar法和Coats-Redfern法)对合成化合物的TG分析结果进行了非等温热分解动力学研究。推断结果表明,合成化合物的第1步热分解为球对称的三维扩散机理(n=2),其动力学方程为dα/dt=1.58×108[1-(1-α)1/3]-1(1-α)2/3exp(-40 931.0/T),求得分解反应的表观活化能E=340.30 kJ/mol,指前因子A=1.05×108 s-1。 标题化合物对紫外光具有光致变色性质,用固体漫反射光谱研究了其光致变色反应动力学。 结果显示,其光致变色反应表现为一级或准一级动力学,速率常数k=9.80×10-5 s-1。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号