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1.
姜廷顺  闵恩泽 《催化学报》1994,15(2):121-126
用水热法合成了镓皂石,并用Al13齐聚物进行交联。经XRD,IF,MASNMR和元素分析表征,结果显示镓存在于粘土层四面体骨架中,交联剂引入量与层四面体中镓含量有关。层与柱键合可能发生在GaO4四面体上。  相似文献   

2.
利用XRD、DTA、IR考察了预焙烧对铝交联蒙脱土(Al-CLM)结构的稳定化作用及引入铂对稳定Al-CLM结构的协同效应;用加压连续流动微反装置研究了Pt/Al-CLM的n-C_8芳构化性能与其结构稳定性的关系。结果表明:经400-500℃的高温预焙烧可使Al-CLM在浸铂过程中保持较高的层结构有序度和规整性,相应保持较大的层间域尺度,对Al-CLM的结构具有稳定作用;引入的铂与Al-CLM的四面体片发生相互作用,可抑制硅氧四面体的扭曲旋转,从而阻抑八面体结构羟基的脱除,具有稳定结构羟基的作用;而Pt/Al-CLM的n-C_8芳构化C_8芳烃收率与其结构的完整性、有线性、相关性。  相似文献   

3.
制备了4-CH3SC6H4NH2(MMA)插层的α-Zr9HPO4)2.H2O,研究了不同实验条件下MMA的插层特性,发现插层反应与MMA和α-ZrP摩尔比R有关;(1)当R〉2时,有插层产物相产生,但是即使在MMA大大过量的条件下,仍然有部分α-ZrP颗粒大小等有关;插层产物的层间距约为2.36nm,,层间距的大小不随反应物浓度,温度等条件变化。  相似文献   

4.
在pH6的HAc-NaAc缓冲溶液和十六烷基三甲基溴化铵(CTMAB)存在下,镓与苯基萤光酮(PF)生成蓝色配合物,配合物的最大吸收波长为565nm,表观摩尔吸光系数ε=1.3×10^5L.mol^-1.cm^-1,测得配合物组成比为Ga:PF=1:4,在25mL溶液中含镓0~10μg遵守比耳定律,经乙酸乙酯萃到镓与干扰元素分离后,方法和于煤中微量镓的测定,结果满意。  相似文献   

5.
在γ-Al2O3中加入Zn2+,Mg2+,Cu2+或Cr3+后用漫反射光谱法研究了它们对随后加人的Co分布的影响,同时还研究了这些离子对水煤气变换反应催化剂CoMoK/Al2O3的催化活性的影响.发现Zn2+,Mg2+具有阻止Co进入载体内层的作用,Cu2+,Cr3+的作用则相反.四面体配位倾向强的金属离子能阻止Co进入载体内层,从而促进水煤气变换反应的催化活性,而八面体配位倾向强的金属离子的效果刚好相反.在650℃下,100gAl2O3含7gMgO时,Mg能最大限度地阻止Co向Al2O3内层扩散,从而提高了CoMok/Al2O3的催化活性.  相似文献   

6.
SAPO-34分子筛晶化机理的研究   总被引:5,自引:1,他引:5  
采用XRD,SEM,IR和CP/MAS及MASNMR等手段,对快速水热合成SAPO34分子筛的全过程进行了监测,研究了由原始凝胶到SAPO34结晶体过程中固相物质的组成结构随晶化时间的变化规律.结果表明,SAPO34晶核的形成过程既是一个硅氧、磷氧和铝氧四面体由无序排列的胶团到有序排列的晶格骨架的重排过程,同时又是羟基缔合脱水环化的过程.晶化分为晶化前期和晶化后期两个阶段.晶化前期,硅原子直接参与晶核的形成和晶粒的长大过程,生成Si(4Al)结构;晶化后期,少量硅以同时取代一对磷铝原子的方式进入分子筛骨架形成Si(3Al),Si(2Al),Si(1Al),Si(0Al)等多种硅结构.但在整个晶化过程中Si(4Al)结构的生成并不排除硅单独取代磷机理的共同作用.  相似文献   

7.
CRINISINE,ANEWALKALOIDFROMCRINUMASIATICUML.VAR.SINICUM(ROXB.EXHERB)BAKER¥RenJiuTANG;NingjiBI(GuangxiInstituteofTraditionalMed...  相似文献   

8.
谭涓  刘中民 《催化学报》1998,19(5):436-441
采用XRD,SEM,IR和CP/MAS及MAS NMR等手段,对快速水热合成SAPO-34分子筛的全过程进行了监测,研究了由原始凝胶到SAPO-34结晶体过程中固相物质的组成结构随晶化时间的变化规律。结果表明,SAPO-34晶核的形成过程既是一个硅氧,磷氧和铝氧四面体由无序排列的胶团到有序排列的晶格骨架的重排过程,同时又是羟基缔合脱水环化的过程。  相似文献   

9.
PNPAR—CTMAB光度法测定水中痕量阴离子表面活性剂   总被引:1,自引:0,他引:1  
本文研究了对硝基偶氮间苯二酚(PNPAR)与溴化十六烷基三甲铵(CTMAB)形成的离子缔合物PNPAR-CTMAB作显色剂与阴离子表面活性剂(AS)的显色反应,发现在pH13.0的NaOH介质中,AS能定量置换出PNPAR-CTMAB中的PNPAR,而使其最大吸收波长630nm处吸光度下降,阴离子表面活性十二烷基苯磺酸钠(SDBS)和十二烷基磺酸钠(SDS)的ε值分别为3.5×10^4,5.8×1  相似文献   

10.
以甲基丙烯酸二甲氨基乙酯溴代乙烷( M A E B) 或丁烷( M A B B) 季胺盐与苯乙烯( St)为单体,采用溶液自由基共聚合方法,合成了一类新型阳离子两亲共聚物.详细地研究了聚合条件及共聚物的溶解性.共聚物“亲油”和“亲水”单元的无规结构被 I R、1 H N M R 及13 C N M R所证实.最后,用线性化( Y B R) 法分别求得 M A E B/ St 和 M A B B/ St 的单体竞聚率,r M A B B =044 ,r St = 015 ,r M A E B= 066 ,r St= 036 .  相似文献   

11.
用水热法合成出两种不同镓含量的镓皂石,并用羟基铝低聚物对其进行了交联。对其表面酸性的考察发现,样品的酸量随嫁含量的增加而增大;样品均含有B酸和L酸中心,交联样品的B酸中心比交联前少。对样品催化性能的研究发现,催化活性与镓含量及酸量呈顺变关系。  相似文献   

12.
The manufacturing methods of cross-linked polyethylene foams are classified into two categories based on a type of cross-linking. One is chemical cross-linking by using peroxide as a cross-linking agent. The other method is cross-linking by irradiation. As for chemical cross-linking, a fairly thick foam sheet can be produced, and a comparatively high degree of cross-linking can be achieved. This means chemical cross-linking excels in thermo-forming but, due to a rough surface, the product is lacking in adhesive property and printability. We studied how to improve the surface condition of foam sheet without damaging the features proceeding from chemical cross-linking. As a result, it has been revealed that at the pre-stage of foaming, and by irradiating the surface at low voltage, the resultant foamed sheet with smooth surfaces and excelling in mechanical properties can be produced.  相似文献   

13.
以XRD、MAS NMR、IR和化学分析等方法研究了镓取代皂石及其羟基铝低聚物交联物。结果表明,Ga占据骨架四面体位置,影响四面体层电荷及Al柱的交联密度。交联物经焙烧后,Al柱与层形成Ga—O—Al_p键,实现了层与柱的交联,而Al_(13)基本结构不变。  相似文献   

14.
Zeman A  Růzicka J  Kuvik V 《Talanta》1966,13(2):271-275
A rapid method for the substoichiometric determination of gallium by neutron-activation analysis has been developed. After irradiation and dissolution of the test sample, gallium carrier is added and two preliminary separation steps are performed: the extraction into chloroform of cupferrates from 7N sulphuric acid and of diethyldithiocarbamates from 2-3N sulphuric acid. The pH of the remaining aqueous phase is then adjusted to 5.5, the solution extracted with a substoichiometric amount of 8-hydroxyquinoline in chloroform and the activity of the gallium hydroxyquinolate extract measured. A simultaneously irradiated gallium standard is treated in exactly the same way. From the activities of these two substoichiometric extracts the amount of gallium originally present in the test sample can be calculated. The method has been applied to the determination of 10(-6) to 10(-3)% of gallium in metallic aluminium and transistor-grade silicon.  相似文献   

15.
The main regularities in the extraction of gallium from alkaline carbonate solutions with phenylfluorone in the system polyethylene glycol (PEG)-sodium carbonate-water were studied by spectrophotometry and inductively coupled plasma mass spectrometry. It was demonstrated that, under these conditions, the distribution coefficient of gallium is above 100 and the recovery is ~98% (at the ratio of phases PEG: salt = 1: 2). The ratio between gallium and the reagent in the complex was determined, and the structure of the coordination sphere of the central atom in the extracted complex was proposed. It was demonstrated that gallium can be determined by the extraction-photometric method at pH 11–14 in the presence of a fivefold amount of aluminum.  相似文献   

16.
A determination method for lead in waste water and effluent was studied using flame atomic absorption spectrometry after preconcentration of lead by the rapid coprecipitation technique with gallium phosphate. Lead ranging from 0.5 to 50 microg was quantitatively coprecipitated with gallium phosphate from 100-150 mL sample solution (pH approximately 5). The presence of gallium phosphate did not affect the atomic absorbance of lead. Since the concentration of gallium in the final sample solution is also measurable by flame atomic absorption spectrometry at 250.0 nm without further dilution, the rapid coprecipitation technique, which does not require complete collection of the precipitate, becomes possible using a known amount of gallium and measuring the concentrations of both lead and gallium in the final sample solution by flame atomic absorption spectrometry. The 32 diverse ions tested gave no significant interferences in the lead determination. The method proposed here is rapid and has good reproducibility.  相似文献   

17.
The differential enthalpies of adsorption of air pollutants such as SO2, NO2, NO on aluminasupported tin and gallium oxides were measured by calorimetry coupled with isothermal volumetry. Whatever the amount of tin or gallium on alumina, the enthalpies of adsorption of SO2 at low coverage were of the same order of magnitude or up to 50 kJ/mol lower than those of the support. The amount of SO2 adsorbed decreased with increasing SnO2 loading and increased with increasing Ga2O3 loading on the alumina. The differential enthalpies of adsorption of NO2 are close to those on the support whatever the amount of tin or gallium (around 120–130 kJ/mol). NO is only reversibly adsorbed on the samples. The calorimetric data of ammonia adsorption are given for comparison.  相似文献   

18.
A determination method for lead in waste water and effluent was studied using flame atomic absorption spectrometry after preconcentration of lead by the rapid coprecipitation technique with gallium phosphate. Lead ranging from 0.5 to 50 μg was quantitatively coprecipitated with gallium phosphate from 100–150 mL sample solution (pH ∼5). The presence of gallium phosphate did not affect the atomic absorbance of lead. Since the concentration of gallium in the final sample solution is also measurable by flame atomic absorption spectrometry at 250.0 nm without further dilution, the rapid coprecipitation technique, which does not require complete collection of the precipitate, becomes possible using a known amount of gallium and measuring the concentrations of both lead and gallium in the final sample solution by flame atomic absorption spectrometry. The 32 diverse ions tested gave no significant interferences in the lead determination. The method proposed here is rapid and has good reproducibility. Received: 16 August 1999 / Revised: 6 October 1999 / Accepted: 14 October 1999  相似文献   

19.
Water could be decomposed into hydrogen and oxygen over Ga-modified ZSM-5 zeolite under UV irradiation. The photocatalytic activity was elevated significantly by supporting the gallium species and was sensitive to the loading amount of gallium species on the ZSM-5 zeolites.  相似文献   

20.
[see reaction]. A gallium hydride reagent, HGaCl2, was found to act as a radical mediator, like tributyltin hydride. Treatment of alkyl halides with the gallium hydride reagent, generated from gallium trichloride and sodium bis(2-methoxyethoxy)aluminum hydride, provided the corresponding reduced products in excellent yields. Radical cyclization of halo acetals was also successful with not only the stoichiometric gallium reagent but also a catalytic amount of gallium trichloride combined with stoichiometric aluminum hydride as a hydride source.  相似文献   

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