KCl—MgCl2—H2O—DMF四元体系25℃时的等温溶度研究

结果表明:25℃时四元体系KCl-MgCl_2-H_0-DMF共有六个结晶区:MgCl_2·6H_2O,KCl·MgC_(12)·6H_2O,MgCl_2·6H_2O·2DMF,MgCl_2·2H_2O·4DMF和MgCl_2·4DMF;有九条单变线和四个四元无变点。其中KCl的相区很大,其他则相当狭小,这个结果对利用有机溶剂进行光卤石加工,分离制取KCl具有一定价值。     

Enhanced catalytic performance for direct synthesis of dimethyl ether from syngas over a La2O3 modified Cu-ZrO2/γ-Al2O3 hybrid catalyst

A series of hybrid catalysts were made by physically mixing Cu-ZrO 2 and γ-Al 2 O 3,for former it was modified with different loadings of La 2 O 3 prepared by co-precipitation method.The catalysts were characterized by BET,XRD,N 2 O-adsorption,EXAFS,H 2-TPR,NH 3-TPD techniques and evaluated in the synthesis of dimethyl ether from syngas.The results show that La 2 O 3 promoted catalysts displayed a significantly better catalytic performance compared with Cu-ZrO 2 /γ-Al 2 O 3 catalyst in CO conversion and DME selectivity,and the optimum catalytic activity was obtained when the content of La 2 O 3 was 12 wt%.The characterizations reveal that high copper dispersion,facile reducibility of copper particles and appropriate amount of acidic sites are responsible for the superior catalytic performance.     

γ-Al2O3负载的金溶胶的尺寸效应对CO催化氧化活性的影响

The relationship between particle size and catalytic activity of gold nanoparticle catalysts with γ-Al2O3 as support has been investigated. The catalysts were prepared via the gold sol with different particle sizes by micelle method, and their structures were characterized by HRTEM and XRD, respectively. Furthermore, the catalytic activities were tested by CO oxidation. Experimental results showed that the catalytic activity became much weaker when gold particles were increased from 3.2 to 6.6 nm. Additionally, the particle size was also a key factor to govern catalytic activity with regard to gold supported on TiO2 prepared by the methods of deposition-precipitation.     

三元体系YCl3-CdCl2-H2O和四元体系YCl3-CdCl2-HCl(～8.8%)-H2O (25 ℃)的相平衡及其固相新化合物的研究

The equilibrium solubilities of the ternary system YCl₃-CdCl₂-H₂O, the quaternary system YCl₃-CdCl₂-HCl(～8.8%)-H₂O were determined at 25 ℃ and the phase diagrams were constructed. The results show that the ternary system was complicated with six equilibrim solid phases CdCl₂·2.5H₂O, CdCl₂·H₂O, 8CdCl₂·YCl₃·15H₂O (8∶1 type), 4CdCl₂·YCl₃·13H₂O(4∶1 type), 5CdCl₂·2YCl₃·26H₂O (5∶2 type) and YCl₃·6H₂O. The quaternary system was also complicated with four equilibrim solid phase CdCl₂·H₂O, 4CdCl₂·YCl₃·13H₂O (4∶1 type), 5CdCl₂·2YCl₃·26H₂O(5∶2 type) and YCl₃·6H₂O. Among the three new compounds 8CdCl₂·YCl₃·15H₂O, 4CdCl₂·YCl₃·13H₂O and 5CdCl₂·2YCl₃·26H₂O, 8CdCl₂·YCl₃·15H₂O was a kind of metastable compound only in ternary system, and it was changed into 4CdCl₂·YCl₃·13H₂O with time. Both 4∶1 type and 5∶2 type existed in ternary and quaternary system, but they were also congruently soluble compounds in quaternary system. They have been prepared from the system and have been characterized by XRD, TC-DTG and DSC.     

稀土元素异硫氰酸盐水合物的低温热容和热力学性质研究——Ⅲ.Sm(NCS)_3·6H_2O,Gd(NCS)_3·6H_2O,Yb(NCS)_3·6H_2O和Y(NCS)_3·6H_2O

用全自动绝热量热计测定了4种稀土异硫氰酸盐六水合物,Sm(NCS)_3·6H_2O,Gd(NCS)_3·6H_2O,Yb(NCS)_3·6H_2O和Y(NCS)_3·6H_2O在13～300 K间的热容,在实验温区上述化合物均未发现反常热容.根据实验热容数据用最小二乘拟合方法得出了计算这4种化合物在13～300 K温区内的热容多项式方程.13K以下的热容用 Debye-Einstein热容函数估算而得.计算了这些化合物在0～300 K间的标准热力学函数及其标准生成Gibbs能.     

催化剂Pd/TiO2-Al2O3低温下催化甲烷燃烧活性及18O同位素交换性能

Pd supported on TiO2-Al2O3 binary oxides prepared by coprecipitation method has been investigated for the total oxidation of methane. All Pd/TiO2-Al2O3 catalysts show higher activity than Pd/Al2O3 and Pd/TiO2. Among them, Pd/2Ti-3Al with a Ti/Al ratio of 2 to 3 has a T90% of 395 ℃ at a gas hourly mass velocity of 33000 mL/（h＊g）, which is at least 50 ℃ lower than that of Pd supported on single metal oxide Al2O3 or TiO2. The results of TPR and ^180-isotope exchange experiments demonstrated that the excellent activity of Pd/2Ti-3Al was due to its high oxygen mobility and moderate reducibility, which is in accordance with our previous work, XPS results indicated that the dispersion of Pd was not the key factor to influence the catalytic activity.     

乙烷氧化脱氢用Ni/Al2O3催化剂中活性镍物种前驱体（英文）

Ni/Al2O3 catalysts for oxidative dehydrogenation(ODH) of ethane were prepared by impregnation of Al2O3 with nickel acetate or nickel nitrate,and by mechanical mixing of NiO and Al2O3.The Ni-based catalysts were characterized by N2 adsorption-desorption,X-ray diffraction,diffuse reflectance UV-visible diffuse reflectance spectroscopy,and temperature-programmed reduction of hydrogen.The results showed that formation of crystalline NiO particles with a size of < 8 nm and/or non-stoichiometric NiO species in the Ni/Al2O3 catalysts led to more active species in ODH of ethane under the investigated reaction conditions.In contrast,tetrahedral Ni species present in the catalysts led to higher selectivity for ethene.Formation of large crystalline NiO particles(22-32 nm) over Ni/Al2O3 catalysts decreased the selectivity for ethene.     

化合物Cs5EuCl8·14H2O和Cs2EuCl5·4H2O的制备和荧光性

The two new compounds Cs₅EuCl₈·14H₅O(5∶1 type) and Cs₂EuCl₅·4H₂O(2∶1 type) were found and syn-thesized from CsCl-EuCl₃-11%HCl-H₂O quaternary systems by phase equilibrium method, and were characterized and measured by ultra-violet absorption spectrometry and fluorescence spectrum. The results show that upconversion spectrum exhibit at 590nm and 610nm exited at 790nm, and the upconversion intensity increases with the EuCl₃ ratio increasing in CsCl.     

Characteristics of La-modified Ni-Al2O3 and Ni-SiO2 catalysts for COx-free hydrogen production by catalytic decomposition of methane

Hydrotalcite precursors of La modified Ni-Al2O3 and Ni-SiO2 catalysts prepared by co-precipitation method and the catalytic activities were examined for the production of COx-free H2 by CH4 decomposition. Physico-chemical characteristics of fresh, reduced and used catalysts were evaluated by XRD, TPR and O2 pulse chemisorptions, TEM and BET-SA techniques. XRD studies showed phases due to hydrotalcite-like precursors in oven dried form produced dispersed NiO species upon calcination in static air above 450 C. Raman spectra of deactivated samples revealed the presence of both ordered and disordered forms of carbon. Ni-La-Al2O3catalyst with a mole ratio of Ni : La : Al = 2 : 0.1 : 0.9 exhibited tremendously high longevity with a hydrogen production rate of 1300 molH2 mol 1 Ni. A direct relationship between Ni metal surface area and hydrogen yields was established.     

Framework Structure of a Synthetic High Silica Zeolite --ZSM-39 from a C_2H_4(OH)_2-H_2O Mixed Solvent System

The structural analogy of clathrate synthesized with natural zeolite framework is well known. HPF_6·6H_2O and (CH_3)_4 (OH)·5H_2O are isostructural with sodalite,melanophlogite is isostructural with the 12 cubic gas hydrate and zeolite ZSM-39 with the 17 gas hydrate. The synthesis of ZSM-39 was first reported by Brace in 1981.Schleker and Meier also obtained the crystals of ZSM-39 with size<10μm and analyzed its crystal stucture by the powder X-ray diffraction.In 1984,Gies solved the crystal structure of dodecasil 3C(ZSM-39) synthesized from an aqueous system in space group F_(ds).In the present paper,we report the framework structure of the high silica zeolite—ZSM-39 obtained from the ethylene glycol-water mixed solvent system.     

Ni/Al2O3 catalysts for CO methanation: Effect of Al2O3 supports calcined at different temperatures

The correlation between phase structures and surface acidity of Al2O3 supports calcined at different temperatures and the catalytic performance of Ni/Al2O3 catalysts in the production of synthetic natural gas(SNG) via CO methanation was systematically investigated. A series of 10 wt% NiO/Al2O3 catalysts were prepared by the conventional impregnation method, and the phase structures and surface acidity of Al2O3 supports were adjusted by calcining the commercial γ-Al2O3 at different temperatures(600–1200 C). CO methanation reaction was carried out in the temperature range of 300–600 C at different weight hourly space velocities(WHSV = 30000 and 120000 mL·g-1h-1) and pressures(0.1 and 3.0 MPa). It was found that high calcination temperature not only led to the growth in Ni particle size, but also weakened the interaction between Ni nanoparticles and Al2O3 supports due to the rapid decrease of the specific surface area and acidity of Al2O3 supports. Interestingly, Ni catalysts supported on Al2O3 calcined at 1200 C(Ni/Al2O3-1200) exhibited the best catalytic activity for CO methanation under different reaction conditions. Lifetime reaction tests also indicated that Ni/Al2O3-1200 was the most active and stable catalyst compared with the other three catalysts, whose supports were calcined at lower temperatures(600, 800 and 1000 C). These findings would therefore be helpful to develop Ni/Al2O3 methanation catalyst for SNG production.     

溶剂热合成具有纳米孔结构的γ -Al2O3

Nanoporous gamma aluminum oxide (γ-Al₂O₃) was synthesized by solvothermal method in the presence of AlCl₃·6H₂O, urea and alcohol. The calcined sample was characterized by XRD, FTIR, TEM, and Nitrogen adsorption-desorption measurement. Results show that the obtained γ-Al₂O₃ is well-dispersed nanoparticles with particle size of 4～7 nm and the product has nano-pore structure with a narrow pore size distribution of 5～20 nm.     

氯化钐与甘氨酸配合物Sm(Gly)2Cl3·3H2O热化学研究

A complex of samarium with glymine， [Sm(Gly)₂Cl₃·3H₂O]， was synthesized and characterized by DSC， TG and DTG. A possible mechanism of thermal decomposition of this complex was suggested. The heat capacities of the complex were measured by a precision adiabatic calorimeter over the temperature range from 82 to 375 K. The solution enthalpies of reactants [SmCl₃·6H₂O+2Gly] and the products [Sm(Gly)₂Cl₃·3H₂O+3H₂O] were determined by an isoperibel solution- reaction calorimeter at 298.15 K， respectively; the standard molar enthalpy of formation of [Sm(Gly)₂Cl₃·3H₂O] was calculated through a designed thermochemical cycle.     

Carbon nanotubes decorated α-Al2O3 containing cobalt nanoparticles for Fischer-Tropsch reaction

A new hierarchical composite consisted of multi-walled carbon nanotubes (CNTs) layer anchored on macroscopic α-Al2O3 host matrix was synthesized and used as support for Fischer-Tropsch synthesis (FTS). The composite constituted by a thin shell of a homogeneous, highly entangled and structure-opened carbon nanotubes network and it exhibited a relatively high and fully accessible specific surface area of 76 m 2 g-1 , compared with that of 5 m 2 g-1 of the original α-Al2O3 support. The metal-support interaction between carbon nanotubes surface and cobalt precursor and high effective surface area led to a relatively high dispersion of cobalt nanoparticles. This hierarchically supported cobalt catalyst exhibited a high FTS activity along with an extremely high selectivity towards liquid hydrocarbons compared with the cobalt-based catalyst supported on pristine α-Al2O3 or on CNTs carriers. This improvement can attribute to the high accessibility of composite surface area comparing with the macroscopic host structure alone or to the bulk CNTs where the nanoscopic dimension induced a dense packing with low mass transfer which favoured the problem of reactants competitive diffusion towards the cobalt active site. In addition, intrinsic thermal conductivity of decorated CNTs could help the heat dissipating throughout the catalyst body, thus avoiding the formation of local hot spots which appeared in high CO conversion under pure syngas feed in FTS reaction. Cobalt supported on CNTs decorated α-Al2O3 catalyst also exhibited satisfied high stability during more than 200 h on stream under relatively severe conditions compared with other catalysts reported in the literature. Finally, the macroscopic shape of such composite easily rendered its usage as catalyst support in a fixed-bed configuration without facing problems of transport and pressure drop as encountered with the bulk CNTs.     

Y(NO_3)_3-H_2O二元体系的研究

Y(NO_3)_3-H_2O二元体系属转熔型,它的平衡固相分别为Y(NO_3)_3·6H_2O、Y(NO_3)·5H_2O和Y(NO_3)_3·4H_2O。在Y(NO_3)_3·6H_2O相区内,Y(NO_3)_3·5H_2O的介稳现象是明显的。过饱和硝酸钇溶液在室温下结晶,常得到Y(NO_3)_3·5H_2O,而不是Y(NO_3)_3·6H_2O。本文认为,P.D.F.衍射卡所载Y(NO_3)_3·6H_2O的x-衍射数据可能是Y(NO_3)_3·5H_2O的数据。     

四元体系CdCl2-LaCl3-(9.7%)HCl-H2O在298K的相平衡及其固相化合物的研究

The equilibrium solubility of the LaCl₃-CdCl₂-(9.7%)HCl-H₂O quaternary system at 298K was determined and the phase diagram was constructed. The results show that the system is complicated with four equilibrium solid- phases CdCl₂·H₂O， 8CdCl₂·LaCl₃·16H₂O(8∶1 type)， 4CdCl₂·LaCl₃·12H₂O(4∶1 type) and LaCl₃·7H₂O， respectively. The two new compounds 8CdCl₂·LaCl₃·16H₂O(8∶1 type) and 4CdCl₂·LaCl₃·12H₂O(4∶1 type) are congruently soluble in ～9.7% HCl-H₂O medium and have not yet been reported in literatures. Both com-pounds have been prepared from the system and have been characterized by XRD， TG-DTG and DSC.     

CRYSTAL STRUCTURE OF TRINUCLEAR MOLYBDENUM CLUSTER H(Mo_3O(OAc)_3Cl_6)·3H_2O

<正> INTRODUCTION. Reacting of MoCl_3·3H_2O with organic ligands to-synthesize di- and trinuclear molybdenum complexes is an interesting research area. We wish to report the crystal structure of the title compound. It is one of our research results on structural chemistry of di- and trinuclear molybdenum complexes. The title compound was synthesized by reacting of MoCl_3·3H_2O with CH_3COCl。     

Ni/TiO2-SiO2上光催化重整葡萄糖以低CO选择性制H2（英文）

Nano-sized Ni particles on TiO2-SiO2 were synthesized by the two methods of photo-assisted deposition(PAD) and impregnation.H2,which is a promising energy carrier,with a low CO concentration was produced by the photocatalytic reforming of glucose(a model biomass) on the Ni/TiO2-SiO2 catalyst.The supported Ni enhanced the rate of H2 production while it suppressed CO selectivity.The catalysts were characterized by X-ray diffraction,X-ray absorption fine structure,transmission electron microscope,and nitrogen adsorption analysis.Both H2 production and CO selectivity were strongly dependent on the preparation method,and PAD-Ni/TiO2-SiO2 was the better catalyst for H2 production with the lowest CO concentration.     

盐卤硼酸盐化学 Ⅹ.MgO·2B2O3-MgCL2-H2O浓盐溶液在20℃时硼酸盐的结晶动力学研究

配制MgO·2B_2O—MgCl_2—H_2O浓盐溶液在20℃恒温静置过程中,第一阶段析出MgO·3B_2O_3·7H_2O,第二阶段析出2MgO·2B_2O_3·MgCl_2·14H_2O。采用一级和二级混合反应速率模型,用计算机对结晶动力学C_B—t实验曲线进行拟合,给出结晶动力学速率方程-r=-dC/dt-k(C-C_(平衡))~2+k’(C-C(平衡))。基于高硼浓盐溶液中硼氧配阴离子是以多粒子共存的设想,提出了这两种水合硼酸镁盐结晶反应过程的机制,结晶过程中溶液pH变化的测定结果证实了这一解释。     

Methane Decomposition over Ni/α-Al2O3 Promoted by La2O3 and CeO2

The decomposition of methane on Ni/a-Al2O3 modified by La2O3 and CeO2 with differ-ent contents has been investigated and the ralationship between methane decomposition and removal of carbon by CO2 over these catalyst has also been studied by pulse-chromatography. The catalysts were characterized by TPR and XRD. It was shown that Ni/a-Al2O3 could be promoted by adding La2O3, and the carbon species produced over this catalyst was activated and eliminated by CO2. But CeO2 would suppress the decomposition of methane over Ni crystallite. Both La2O3 and CeO2 can inhibit aggregation of the Ni particles. Decomposition of methane over the Ni-based catalysts is structure sensitive to a certain extent.