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1.
Cu修饰的MCM—41的合成,表征及对芳烃羟化反应催化作?…   总被引:15,自引:1,他引:14  
利用MCM-41形成过程中协同自组装特点,在合成过程中引入Cu(NH3)4^2+,制备出过渡金属表面修饰的纯硅介孔分子筛Cu-MCM-41,采用XRD,ICP,ESR,N2吸附等手段确定Cu处于MCM-41的表面,取代了端羟基中氢的位置,与骨架桥氧和硅羟基中的氧配位,利用苯酚羟化反应为探针,考察了Cu-MCM-41的催化活性。结果表明,Cu-MCM-41具有很高的苯酚羟化活性,与TS-1分子筛的催  相似文献   

2.
CuZSM-5分子筛上苯酚羟化制苯二酚   总被引:4,自引:0,他引:4  
在Na2O-SiO2-CuO-H2O体系中以15%TPABr-85%HMDA为模板剂合成了CuZSM-5分子筛,并用XRD,IR及SEM等方法进行了表征,考察了CuZSM-5分子筛催化苯酚与过氧化氢的羟化活性,研究了催化剂用量、反应温度、反应时间及n(PhOH)/n(H2O2)等对羟化活性的影响.  相似文献   

3.
CuZSM—5分子筛上苯酚羟化制苯二酚   总被引:1,自引:0,他引:1  
于剑锋  张春雷 《催化学报》1997,18(2):130-134
在Na2O-SiO2-CuO-H2O体系中以15%TPABr-85%HMDA为模板剂合成了CuZSM-5分子筛,并用XRD,IR及SEM等方法进行了表征,考察了CuZSM-5分子筛催化苯酚与过氧化氢的羟化活性,研究了催化剂用量,反应温度,反应时间及n(PbOH)/n(H2O2)等对羟化活性的影响。  相似文献   

4.
八羟基喹啉铁(Ⅱ)/MCM-41对苯酚羟化的催化作用   总被引:6,自引:0,他引:6  
刘持标  叶兴凯  吴越 《催化学报》1997,18(2):140-143
利用MCM-41中孔分子筛为载体,制备了负载型八羟基喹啉铁(Ⅱ)/MCM-41(简记为Fe(Ⅱ)-Qx/MCM-41)催化剂.XRD,IR证明八羟基喹啉铁(Ⅱ)配合物成功地负载于MCM-41分子筛中.考察了八羟基喹啉铁(Ⅱ)/MCM-41对苯酚羟化反应的催化作用,和未负载的配合物相比,苯酚的转化率、对苯二酚的选择性以及H2O2的利用率都有显著的提高.同时也探讨了温度、反应介质及介质pH值对苯酚羟化反应的影响.结果表明,随着温度的提高,苯酚的转化率增加,但温度太高,易导致副产物增多;有机溶剂不利于羟化反应的进行,水是实验条件下苯酚羟化反应的最佳反应介质;在一定程度上,pH值越低,越有利于反应活性的提高,若pH值太低,活性反而下降,pH值升高不利于苯酚羟化反应的进行.该催化剂也具有较高的稳定性.  相似文献   

5.
杂原子HMS介孔分子筛的催化脱氢和加氢脱硫性能   总被引:6,自引:1,他引:6  
李惠云  孙渝  乐英红  高滋 《催化学报》1999,20(4):455-458
MCM41[1]和HMS[2]等介孔分子筛对大分子的扩散阻力较小且具有良好的热稳定性,特别是在合成中可以直接将各种杂原子引入骨架,从而调变其催化性能,因此目前介孔分子筛在催化中的应用引起了各国研究者的广泛兴趣.Ti,Zr,V,Cr,Mn,Cu和Fe...  相似文献   

6.
刘持标  叶兴凯 《催化学报》1997,18(2):140-143
利用MCM-41中孔分子筛为载体,制备了我载型八羟基喹啉铁/MCM-41催化剂。XRD,IR证明八羟基喹吉林 铁配合物成功地负载于MCM-41分子筛中。考察了八羟基喹啉铁/MCM-41对苯酚羟化反应的催化作用,和未负载的配合物相比,苯酚的转化率,对苯二酚的选择以及H2O2的利用率都有显著的提高。  相似文献   

7.
超大孔Fe和V—Ti分子筛的合成   总被引:1,自引:0,他引:1  
袁忠勇  刘述全 《分子催化》1995,9(6):457-463
水热法合成了具有超大孔MCM-41分子筛结构的含Fe和V-Ti分子筛,通过XRD,骨架IR,ESR,^29SiMAS NMR,紫外漫反射等测试表征证实,Fe原子在FeMCM-41分子筛骨架上,V和Ti同是进入V-TiMCM-41分子筛骨架。  相似文献   

8.
内嵌型介孔分子筛的合成   总被引:5,自引:0,他引:5  
用表面活性剂十六烷基三甲基氢氧化铵在溶液中形成的液晶相胶态分子团作为模板剂,同时在分子团憎水基团内部导入对乏燃料中钯离子有特效选择萃取效应的协萃剂TOPO-P204,通过表面活性剂亲水基团与易水解的有机硅酸盐阴离子之间的自组织过程,合成了内嵌型介孔分子筛固体吸附剂MCM-TP,经TEM,XRD,29Si-MASNMR测试,与MCM-41介孔分子筛有相似的孔道结构,但其晶胞参数有所增加,水热稳定性有明显的改善.用于提取乏燃料中的钯,饱和吸附Pd容量可达0.015mmol/g.  相似文献   

9.
以十六烷基三甲基溴化铵(CTAB)作模板剂,研究了水热体系中中孔MCM-41分子筛的合成条件。在H_2O/Si介于12~100,Si/Al介于10~∞,CTAB/Si介于0.08~0.2时,可以合成出MCM-41分子筛。在加入煤油等混合烃的合成体系中,可以合成出孔径大于4nm的MCM-41分子筛。用XRD、SEM、N_2吸附对合成样品加以表征,证明它们具有典型的中孔分子筛特性。探针反应证明它具有中强酸中心。  相似文献   

10.
Eu(TTA)3/MCM—41介孔复合体的溶胶—凝胶法组装   总被引:2,自引:0,他引:2  
利用溶胶-凝胶法将稀土的Eu(TTA)3组装到MCM-41介孔分子筛的孔道中,并初步认定客体分子Eu(TTA)3是以加合物形式包裹于表面活性剂胶束中。该法制得的介孔复合体Eu(TTA)3/MCM-41,用XRD、HRTEM技术证实有短程有序的,规整的六方介孔结构和大小分布均匀的纳米晶粒。对其光致发光和荧光寿命的研究发现,与乙醇溶液中相比,Eu^3+的荧光寿命没有发生改变,但Stokes位移却明显增大;复合体中,能量是从主体MCM-41传递到客体Eu(TTA)3上。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.
Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position.  相似文献   

14.
The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the best fitting experimental data. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

15.
Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6.  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

17.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

18.
潘素娟  全灿  周俊波 《化学通报》2014,77(12):1165-1170
测量不确定度是表征合理地赋予被测量之值的分散性的参数。本文针对化学计量不确定度评定基础模型仅适用于线性模型、概率分布为正态分布或缩放位移t分布等局限,介绍了近年来不确定度评定的研究热点:蒙特卡罗方法(Monte Carlo Method,MCM),不确定度评定的来源、评定概念、评估方法及其发展过程,扩大了测量不确定度评定与表示的适用范围。  相似文献   

19.
微量钙的测定方法研究进展   总被引:5,自引:0,他引:5  
介绍了1995-2006年期间测定微量和痕量钙的方法,如电感耦合等离子体-原子发射光谱法、原子吸收光谱法以及离子色谱法等的工作原理和特点,并说明了其测定微量钙的应用领域。并对微量钙的测定技术进行了展望(引用文献55篇)。  相似文献   

20.
Thermal behaviour of sodium oxo-salts of sulphur: Na2SO4, Na2S2O7, Na2S2O6, Na2SO3, Na2S2O5, Na2S2O4, Na2S2O3, Na2S3O6 and of sulphides Na2S and Na2S2 was studied on heating up to 1000°C. The experiments were performed with anhydrous compounds obtained from commercial products by recrystallisation and dehydration. The stage mechanisms of decomposition of anionic sub-lattices of the salts have been proposed basing on the Górski’s morphological classification of simple species. The thermal stability and the stage decomposition mechanisms were correlated with the structure and the potential chemical properties of the salt anions. The thermal decomposition processes were studied by means of thermal analysis, and the decomposition products were identified by means of X-ray phase analysis.  相似文献   

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