NTO稀土盐的合成,结构表征和热分解机理

用３－硝基－１，２，４－三唑－５－酮（ＮＴＯ）的锂盐与稀土的硝酸盐在水溶液中反应，制备了１１种稀土的ＮＴＯ盐，用现代仪器分析方法确证了它们的组成式为ＲＥ（ＮＴＯ）＿３·ｎＨ＿２Ｏ，当ＲＥ为Ｙ、ｌａ、ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ和Ｙｂ时，ｎ分别为６、７、７、７、８、７、７、７、５、５和６，并用ＤＳＣ、ＴＧ－ＤＴＧ和ＦＴ－ＩＲ技术研究了这些盐在等速升温条件下的热分解机理。     

间硝基苯甲酸稀土配合物的热分解

用TG-DTA,高温X-射线衍射研究了稀土间硝基苯甲酸配合物LnL_3·nH_2O(n=2,Ln=La→Lu+Y;n=0,Ln=Sc,HL=间硝基苯甲酸)的热分解行为,DSC测定其脱水相变过程中的热力学函数,同时用透射电镜观察了热分解产物的超微性。     

苯甲酸钡的热分解机理

碱土金属苯甲酸盐是一类比较稳定的化合物,对其已有的报道主要涉及含结晶水碱土金属苯甲酸盐的红外光谱和热分解过程,这些热分解仅涉及失水过程和固体残留物的分析［１～３］。我们首次用半固相法合成了苯甲酸钡,并对无水苯甲酸钡在氮气中热分解的气相凝聚物进行了分析...     

用色谱—质谱和质量以谱研究苯甲酸钐热分解反应

为合成某些芳香族有机化合物提供一种新途径，用色谱－质谱联用技术和质量色谱法研究了苯甲酸钐的热分解反应产物。其热分解产物溶入丙酮后有大量９，１０－蒽醌析出，其丙酮溶液中还含有１，２－二苯甲酰基苯（２５．６％）、苯甲酸（１８．７％）、二苯酮（１４．４％）、９－勿酮（８．２％）、９－苯甲勿（４．９％）、取苯（３．６％）、二苯甲烷（２．３％）、３－甲酰苯基联苯（２．１％）、二苯基乙二酮（１．９％）、４－甲     

邻氯苯甲酸稀土配合物的合成、表征及结构

本文合成了邻氯苯甲酸与十五种稀土的配合物REL~3·H~2O(RE=Y,La～Lu,L=Clc~6H~4CO~2H),研究了它们的热分解及红外光谱.测定了钕、铽及镥三种稀土的配合物晶体结构,均属单斜晶系,空间群P2~1/n,稀土离子配位数为9,配合物呈无限链状聚合结构.     

苯甲酸钐的水热合成和热分解反应机理

用水热法合成了无水苯甲酸钐配合物,经元素分析、IR和X射线粉末衍射表征了该配合物,系层状结构,属单斜晶系。用TG、DTA、IR、色谱-质谱联用仪研究了它的热分解机理。在氮气氛下,热分解分两步进行:第一步分解生成钐的二碳酸一氧盐和有机化合物。生成的有机化合物成分比较复杂,主要成分为苯甲酸、二苯甲酮、9,10-蒽醌和1,3-二苯基异苯并呋喃等。第二步二碳酸一氧盐进一步分解生成氧化钐和二氧化碳。     

肌肉醇取代苯甲酸盐的合成及生物活性

本文以硫脲和硫酸二甲酯为原料反应生成S-甲基异硫脲硫酸盐,再与2-甲基氨基乙醇反应生成肌肉醇硫酸盐,分离出肌肉醇碱,最后与具有生物活性的取代苯甲酸反应生成了7种肌肉醇取代苯甲酸盐。化合物结构经IR,1H NMR和元素分析进行表征,初步室内生测结果表明该类化合物具有一定的抑菌活性。     

稀土乙酸盐水合物热分解机理的研究

采用TG—DTG和DSC法,在空气气氛下对14种稀土乙酸盐水合物(Ln(Ac)_3·nH_2O,Ln=La～Lu+Y,除Ce、Pm,n=4或5]的热分解机理进行研究。热分解机理在钕、钆处发生转折。无水盐的形成温度随原子序数的增加而降低。采用Freemen-Carroll和Kissinger法计算了稀土乙酸盐脱水、分解过程的活化能,以脱水过程的活化能对原子序数作图呈“斜W效应”。用DSC测定了稀土乙酸盐脱水、分解过程的焓变。     

间甲基苯甲酸稀土配合物的合成及晶体结构

本文合成了间甲基苯甲酸与十五种稀土元素的配合物REL3(RE=Y, Ln～Lu;HL=m～CH3C6H4CO2H), 研究了它们的红外光谱并测定了钕和铽两种稀土配合物的晶体结构, 两者均属单斜晶系, 空间群P2~1/n, 钕离子配位数为9, 铽离子配位数为8, 配合物均具有无限链状聚合结构。     

轻稀土水合硝酸盐的热分解

用TG-DTG法研究轻稀土La、Ce、Pr、Nd、Sm的13种水合硝酸盐热分解过程,通过IR对反应物、中间产物和最终产物进行鉴别。发现中间产物均有低水合物、无水盐和碱式盐(铈除外),最终产物都是氧化物。提出它们的热分解机理。另外,用Kissinger法计算了一些脱水过程的表观活化能。     

Synthesis, Characterization, and Thermal Decomposition of Double Rare Earth Monomethylammonium Selenates

Summary.  Double rare earth monomethylammonium selenates of the general formula CH₃NH₃ Ln (SeO₄)₂·5H₂O (Ln = Sm, Eu, Gd, Tb, Ho, Y) were synthesized and characterized using X-ray powder diffraction and infrared spectroscopy. The thermal decomposition of the compounds were investigated using TG, DTG, and DTA techniques. Corresponding author. E-mail: vrajgaonkar@yahoo.com, vrajgaonkar@mail.mu.ac.in Received November 5, 2001. Accepted (revised) March 6, 2002     

Hydrothermal Synthesis,Crystal Structure and Thermal Stability of two 3d‐4f Heterometallic Coordination Polymers

Two new 3d‐4f heterometallic coordination polymers, [LnCu(nic)₂(ox)]·2H₂O (Ln = Sm( 1 ), Dy ( 2 ), ox = oxalate anion, Hnic = nicotinic acid) were synthesized and characterized by elementary analysis, IR spectroscopy and thermogravimetric analysis, as well as single‐crystal X‐ray diffraction. The two structures exhibit the same unusual 3D microporous heterometallic coordination frameworks with 13.7 % voids occupied by guest water molecules.     

CaBPO5∶RE(RE=Eu,Tb)的水热合成及其发光特性

利用水热法合成了CaBPO5∶RE(RE=Eu,Tb)荧光体并测试了其结构和光谱, 讨论了其发光性质, 并与高温固相法合成的产物作了对比. 结果表明, 由于电子转移, Eu3+, Tb3+和Eu2+共存于同一体系中, 而且Eu2+的发射位置从402 nm移至428 nm. 在双掺杂体系中引入Ce3+, Eu3+, Tb3+和Eu2+的发光强度均有所增强, 这可能是Ce3+与Eu3+之间的电子转移及各种稀土离子之间能量传递相互竞争的结果.     

5-氯-2-甲氧基苯甲酸与1,10-邻菲啰啉稀土配合物的合成、表征及热分解机理

合成了三种稀土配合物[Ln(5-Cl-2-MOBA)3phen]2(Ln=Nd(1),Eu(2),Ho(3);5-Cl-2-MOBA:5-氯-2-甲氧基苯甲酸根;phen:1,10-邻菲啰啉),通过元素分析、热重-微分热重-差示扫描量热(TG-DTG-DSC)、红外光谱(IR)、紫外光谱(UV)及摩尔电导等技术对标题配合物进行了表征.荧光光谱表明配合物(2)发出铕离子的特征荧光.用热分析/傅里叶变换红外(TG-DSC/FTIR)联用技术,阐明标题配合物的热分解反应机理,并分析了逸出气体的三维(3D)红外光谱.     

Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.     

New Rare‐Earth Metal Germanides RE2Ge9 (RE = Nd,Sm) by Thermal Decomposition of High‐Pressure Phases REGe5

The rare‐earth metal germanides RE₂Ge₉ (RE = Nd, Sm) have been prepared by thermal decomposition of the metastable high‐pressure phases REGe₅ at ambient pressure. The compounds adopt an orthorhombic unit cell with a = 396.34(4) pm; b = 954.05(8) pm and c = 1238.4(1) pm for Nd₂Ge₉ and a = 395.46(7) pm; b = 946.4(2) pm and c = 1232.1(3) pm for Sm₂Ge₉. Crystal structure refinements reveal space group Pmmn (No. 59) for Nd₂Ge₉. The atomic pattern resembles an ordered defect variety of the pentagermanide motif REGe₅ (RE = La; Nd, Sm, Gd, Tb) comprising corrugated germanium layers. These condense into a three‐dimensional network interconnected by eight‐coordinated germanium atoms. The resulting framework channels along [100] enclose the neodymium atoms. With respect to the atomic arrangement of the pentagermanides, half of the interlayer germanium atoms are eliminated in an ordered way so that occupied and empty germanium columns alternate along [001]. The rare‐earth metal atoms of both types of compounds, REGe₅ and RE₂Ge₉, exhibit the electronic states 4f ³ and 4f ⁵ (oxidation state +3) for neodymium and samarium, respectively, evidencing that the modification of the germanium network leaves the electron configuration of the metal atoms unaffected.     

Synthesis and Thermal Decomposition Mechanism of Rare Earth （RE=La, Y, Gd） Salicylates

The rare earth (RE=La, Y, Gd) salicylates were synthesized by the rheological phase reaction method. The complexes were characterized by elemental analysis, infrared spectra (IR), X-ray powder diffraction (XRD) and thermal gravity analysis (TG). They can be represented by general formula RE(HSal)3 (RE=La, Y, Gd; HSal=C6Ha(OH)COO). The crystals of them are monoclinic and have layered structure. The mechanism of thermal decomposition of rare earth salicylates was studied by using TG, DTA, IR and gas chromatography-mass spectrometry (GC-MS). The thermal decomposition of the rare earth salicylates in nitrogen gas proceeded in three stages: firstly, they were decomposed to form RE2(Sal)3 (Sal=C6H4OCOO) and salicylic acid; then, RE2(Sal)3 were decomposed further to form RE2O(CO3)2 and some organic compounds; finally, RE2O(CO3)2 were decomposed to form rare earth metal oxides (RE2O3) and carbon dioxide. The organic compounds obtained from the second step of the reaction are mainly dibenzofuran, xanthenone, 6H-benzo[c]chromen-6-one, 6-phenyl-6H-benzo[c]chromene, and 1,3-diphenyl-1, 3-dihydro-2-benzofuran.     

Thermal degradation study of gadolinium and lutetium methanesulfonates

The synthesis, characterization and thermal degradation study of gadolinium and lutetium methanesulfonates is reported. The prepared salts were characterized by elemental analysis and infrared spectroscopy. The thermal degradation study was performed by using thermogravimetry (TG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). By using thermogravimetric data, a kinetic study of the dehydration of Gd and Lu methanesulfonates is performed employing the Coats-Redfern and Zsakó methods. It is verified that under heating, the gadolinium and lutetium methanesulfonates suffer three main processes: dehydration, thermal degradation and oxide formation. The thermal degradation products were characterized by infrared spectroscopy and X-diffractometry. Furthermore, depending on the atmosphere nature, i.e. inert or oxidant, the thermal degradation process could be endothermic (N₂) or exothermic (air).     

黑山热液型矿床稀土元素的地球化学行为

通过对岩石,矿石的稀土组成研究,揭示含矿热液稀土总旧为２．４８４－１１．７７８μｇ．ｇ＾－１,富集轻稀土型分布模式及铕,铈负异常。δＥｕ和δＣｅ表明从早至晚热液体系向氧化程度增加的方向演化。     

溶剂热合成Cu2O微球及其对高氯酸铵热分解的催化作用

以聚乙烯吡咯烷酮(PVP)为添加剂,利用溶剂热法合成了Cu2O微球.考察了PVP用量以及反应温度对产物形貌的影响,并在反应时间为2.5与4.5h时分别合成了直径为100-200nm和1μm的Cu2O微球.同时,利用差热分析(DTA)技术考察了不同直径的Cu2O微球对高氯酸铵(AP)热分解的催化效果,结果表明:添加2%(w)的直径为100-200nm和1μm的Cu2O微球使得AP的高温分解温度分别降低了116和118°C,AP在低温阶段的分解量也明显提高.