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1.
用八羰基合二钴在相转移催化条件下合成1—萘乙酸   总被引:1,自引:0,他引:1  
戴金水 《应用化学》1998,15(1):86-87
1一荣乙酸是一种植物生长调节剂,也是合成茶乙酸甲酯(另一种优良的植物生长调节剂)的原料.其合成方法有多种“’“.本文研究了在常压下,利用CO。(CO)s在相转移催化条件下,使1一氯甲基素和一氧化碳直接反应,转化为帮乙酸的合成方法,气相色谱分析法研究了反应温度、催化剂用量等反应条件对转化率的影响.SP-3410型气相色谱仪(北京分析仪器厂),岛津IR-44O红外光谱仪(日本),EM-36060MHZ核磁共振仪(上海),HP5890-5971色谱一质谱联用仪(美国).l一氯甲基素(按文献[3」制备,纯度95%),八谈基合二钻(AR),…  相似文献   

2.
EXAFS研究合成甲醇催化剂Cu/ZnO/MxOy   总被引:1,自引:0,他引:1  
有关CO。+H。合成甲醇催化剂的研究已有许多报道[‘-’j,但目前对活性中心及反应机理的认识仍不~致,其中对活性中心的看法归纳起来有3种:(1)Cll为活性中心“‘;(2)Cll”为活性中心[’j;(3)Cll-CtJ”为活性中心[‘1.研究发现,第三组分(如AI刀。)的加入可防止Cu粒子的烧结[’],使Cu产生无序及缺陷结构,有利于CO。的吸附、活化[‘j及起到高分散Cu/Zno的稳定剂的作用[’j.由于三组分催化剂结构的多相性和准非晶态性,通常的XRD方法难以明确了解其结构,而EXAFS方法对研究局部有序结构特别有效.本文以Z…  相似文献   

3.
采用共沉淀法和金属有机配合物固载法,分别制备了钴氧化物负载的纳米金催化剂.考察了该催化剂对CO低温氧化反应的催化活性及其制备方法和制备条件,如焙烧温度和时间、金的负载量、活性组分前体、沉淀剂的滴加顺序等因素对催化性能的影响.结果表明:严格控制制备条件.上述两种方法制备的3%Au/Co3O4催化剂,对CO氧化反应都具有很高的催化活性,可分别于-22℃和-5℃将空气中1%的CO完全转化为CO2.:XRD和TEM测试结果显示.催化剂上的金颗粒大小在10nm范围内,载体为适度结晶的四氧化三钴.  相似文献   

4.
 采用水热合成法、溶胶凝胶法和共沉淀-负载法制备了相同NiO含量的Ni/ZrO2-CeO2-Al2O3催化剂,考察了它们在CH4-CO2重整反应中的催化性能及稳定性,测定了积碳量.用CO2程序升温脱附方法测试了它们的CO2吸附性能,用H2程序升温脱附方法测试了表面Ni的分散度.结果表明,随温度升高,CH4和CO2转化率降低的顺序是:溶胶凝胶法≈共沉淀-负载法>水热合成法,并且反应产物中n(CO)/n(H2)比随温度升高而降低.水热法和共沉淀-负载法制备的催化剂稳定性好,且前者的活性比后者高;溶胶凝胶法制得的催化剂活性较高,但易失活.积碳量大小顺序是:水热法>溶胶凝胶法>共沉淀-负载法.与其他方法制备的催化剂相比,水热法制备的催化剂对CO2的吸附量更大,\r\n而且积碳主要存在于载体上,从而保证了催化剂的稳定性.  相似文献   

5.
周浩  姜玄珍 《催化学报》2004,25(4):257-258
 在温和条件下,将原位合成的Na[Co(CO)4]配合物首次用于催化一氯丙酮羰基化合成乙酰乙酸甲酯,考察了不同的碱性试剂、一氧化碳压力及反应温度对产物选择性和收率的影响,优化了反应条件,并探讨了可能的反应机理.  相似文献   

6.
钴系非晶合金超细微粒金属微观状态的研究   总被引:3,自引:0,他引:3  
过渡金属(Fe、Co、Ni)一类金属(B、P)非品合金超细微粒催化剂金属-类金属的相互作用是影响其催化性能的重要因素.B、P组元的加入能显著地改变过渡金属的催化活性和催化选择性;许多研究者都认为在过渡金属与B、P之间存在化学键合作用且有电子的转移,但对电子转移的方向仍有争议.前文我们报导了CoB非晶态合金超细微粒催化剂的表面性质和催化性能问,以及掺入P后对CoB已非晶态合金超细微粒催化剂性能的影响.本文采用了乙烯加氢反应作为探针,通过测定金属Co和CoB、CoPB非晶态合金超细微粒催化剂的乙烯加氢反应活化能;获得了…  相似文献   

7.
 用不同链长度的十二胺,十四胺,十六胺和十八胺等伯胺为模板\r\n剂合成了具有不同孔径大小的HMS中孔分子筛.XRD和低温氮吸附测定表\r\n明,HMS具有典型的中孔分子筛特征,且其孔径大小随HMS合成中所用模\r\n板剂链长度的增加而增加.以HMS为载体,采用孔体积浸渍法制备了负\r\n载量为7.5%的钴催化剂,在接近工业试验条件下(n(H2)/n(CO)\r\n=2.1,GHSV=500h-1,p=2.0MPa,θ=227℃)考察了载体孔径大\r\n小对费-托合成反应性能的影响.结果表明,与常规的SiO2载体相比,\r\nHMS负载钴催化剂具有更高的催化活性和C5+选择性;而且,CO转化率\r\n,C5+选择性及产物中的蜡油比均随着HMS载体孔径的增大而升高.以\r\n7.5%Co/HMS-18为催化剂,CO转化率为78.0%,C5+选择性为80.\r\n8%,蜡油比为11.1.  相似文献   

8.
Cu/SiO2表面性质对甲醇脱氢反应性能的影响   总被引:3,自引:0,他引:3  
甲醇催化脱氢是将甲醇转化为其它有机化学品的一条有效途径,该反应的产物依反应条件以及催化剂不同有可能是无水甲醛、甲酸甲酯或CO’‘-”.很多研究结果表明铜基催化剂对甲醇脱氢反应表现出较好的催化性能’‘-”,但催化剂的表面结构对其反应性能的影响以及反应过程中由于催化剂结构变化引起的活性和选择性的变化规律还缺乏深入研究.本文以Cll/Sic。为研究对象,考察了制备方法对催化剂甲醇脱氧反应性能的影响.1实验部分1.1催化剂制备负载型催化剂以微球型Sic。作为载体(BET比表面积3635mZ·g-‘),分别以钢氨溶液和硝酸铜…  相似文献   

9.
长期以来,人们对Co(I)与SChiff诚配合物的研究范围限于同种配体的多,对复合配体络合物的研究较少·我们曾合成了过渡金属与N一本基水杨醛亚胺及其衍生物(以L表示)的络合物Mll)L。,并研究了它们的晶体结构[‘一句.结构表明,Mll)L。的中心离子与配位原子形成四面体构型·为了研究复合配体对低价CO(11)离子络合配位构型的影响,探索复合配体络合物的结构与性能的关系,我们选用易与低价金属形成稳定络合物的双齿配体二氯杂菲和配合物CO(11)L。为反应物,合成了d’组态高自旅Co11)离子的复合配体络合物·本文将报道该络…  相似文献   

10.
常温常压下高效快速合成羰基钴的新方法   总被引:4,自引:1,他引:4  
常温常压下高效快速合成羰基钴的新方法李光兴郑京京(华中理工大学化学系武汉430074)关键词羰基钴合成方法羰基化Raney-Ni羰基钴是一种重要的羰基络合物,也是一种重要的催化剂[1].常见的单核羰基钴主要有3种形态:Co2(CO)8、HCo(CO)...  相似文献   

11.
Solvent extraction studies have been made on some metals: In/III/-Tl/III/ and Hg/II/-Cd/II/-Co/II/, from ammonium thiocyanate solutions by dialkyl sulphoxides. Separation of these metals from one another can be achieved by suitable choice of the extracted conditions. The nature of the extractable metal species has been elucidated.  相似文献   

12.
Summary Single reverse water-gas shift (RWGS) and dehydrogenation of propane with CO2(DH-CO2) reactions in the presence and absence of the CrOx/SiO2 catalyst have been studied between 673 and 873 K. It was found that the CrOx/SiO2 catalyst is active both in the dehydrogenation of propane and in the RWGS reactions. The obtained results suggest that the dehydrogenation of propane to propene in the presence of CO2on CrOx/SiO2can be facilitated by the RWGS reaction.</o:p>  相似文献   

13.
Chlorobis/-diketonato/ oxotechnetium/V/ complexes [TcOCl/-dik/2, -diketone=acetylacetone, benzoylacetone and dibenzoylmethane] were newly synthesized using macroamount of99Tc. These complexes were further separated into geometrical isomers. Furthermore, an improvement of the yields for the syntheses of tris/-dike-tonato/technetium/III/ complexes [Tc/-dik/3, -diketone=acetylacetone, benzoylacetone and 2-thenoyltrifluoroacetone] was examined using Tc/III/-thiourea complexes as a starting material.  相似文献   

14.
The crystal structure of trisodium monophosphate hemihydrate was determined. The space group is C2c and a unit cell contains eight formula units. The unit cell dimensions of Na3PO4 · 12H2O are a = 9.631(3), b = 5.416(2), c = 16.938(8) Å, β = 102.60(5)°. The final R value is 0.027 for a set of 1430 independent reflections. This atomic arrangement is mainly a three-dimensional network of distorted NaO6 octahedra. The hydrogen bonding scheme is given.  相似文献   

15.
Summary CexTi1-xO2 and H3PW12O40/CexTi1-xO2 catalysts were prepared using a sol-gel method, and applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. H3PW12O40/CexTi1-xO2 showed a better catalytic performance than the corresponding CexTi1-xO2, due to the bifunctional catalysis of Br?nsted acid sites (provided by H3PW12O40) and base sites (provided by CexTi1-xO2). H3PW12O40/Ce0.1Ti0.9O2 showed the highest catalytic performance among the H3PW12O40/CexTi1-xO2 catalysts.  相似文献   

16.
Doped-rutile has been traditionally used in ceramic pigments for its intense optical properties. In this paper, we compare the classical ceramic synthesis of Ti1−2xNbxNixO2−x/2 system with the sol-gel methodology, which allows a reduction of the anatase-rutile transformation temperature. The composition was optimised in order to obtain a unique rutile phase with the minimum amount of pollutant Ni(II) and enhanced chromatic coordinates. Incorporation of the doping ions in the rutile structure was corroborated by XRD and Rietveld refinements. The species responsible for the colour mechanism were studied by different techniques. UV-VIS spectroscopy showed the characteristic features of Ni2+ ions, whose existence was corroborated by EPR and magnetic measurements. From these results, (Ni,Nb)doped-TiO2 powder samples can be now shaped as thin films, monoliths, etc. by using sol-gel methodology without modifying their properties. This study introduces new possibilities of coloured TiO2-based solid solutions in new combined advanced applications (colouring agent and photocatalyst, etc.).  相似文献   

17.
LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究   总被引:1,自引:0,他引:1       下载免费PDF全文
A series of single-phase LixNi0.8-yCo0.2ZnyOp(0.96 ≤x≤ 1.10, 0 ≤y≤ 0.05, 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method, in which LiOH·H2O, Zn-doped spherical Ni(OH)2 and Co2O3 were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD, SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine, narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity, but also a better cycling stability characterization than the un-doped one. The Li1.06Ni0.75Co0.22Zn0.03O2.03 material has an initial reversible capacity as high as 160.5mAh·g-1; and a first discharge efficiency 89.2%, and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.  相似文献   

18.
Summary A strong promoting effect of the presence of C3H8or C3H6was determined for the combustion of CH4in excess oxygen, over pre-sulfated 1%Pt/g-Al2O3and pre-sulfated 1%Pt-2%Sn/g-Al2O3catalysts.</o:p>  相似文献   

19.
采用高温固相法制备了4种高纯度晶相组成的LixZryOz三元化合物,研究了焙烧温度、时间、反应物的种类和初始反应物物质的量比对产物组成的影响,进一步用XRD、SEM及BET分析方法对产物的晶相结构、表面形貌及比表面积进行了表征.实验结果表明,Li2CO3与ZrO2在适当条件下可以合成得到单斜相Li3ZrO3;以LiOH替代Li2CO3,在适当条件下可以分别合成得到四方相Li2ZrO3和三斜/单斜相Li6Zr2O7;进一步以Zr(NO3)4·5H2O代替Zr02,可将单斜相Li6Zr2O7的制备时间由96 h缩短至24 h.SEM照片显示产物硬团聚明显,粒径分布在1~10μm间,BET分析表明样品比表面积处于1.0~9.0 m2·g-1间分布,反应过程中锂的过量以及长时间高温焙烧是引起产物粒径长大和产生硬团聚的主要原因.  相似文献   

20.
Nitrogen substituted yellow colored anatase TiO2−xNx and Fe-N co-doped Ti1−yFeyO2−xNx have been easily synthesized by novel hydrazine method. White anatase TiO2−δ and N/Fe-N-doped samples are semiconducting and the presence of ESR signals at g ∼1.994-2.0025 supports the oxygen vacancy and g∼4.3 indicates Fe3+ in the lattice. TiO2−xNx has higher conductivity than TiO2−x and Fe/Fe-N-doped anatase and the UV absorption edge of white TiO2−x extends in the visible region in N, Fe and Fe-N co-doped TiO2, which show, respectively, two band gaps at ∼3.25/2.63, ∼3.31/2.44 and 2.8/2.44 eV. An activation energy of ∼1.8 eV is observed in Arrhenius log resistivity vs. 1/T plots for all samples. All TiO2 and Fe-doped TiO2 show low 2-propanol photodegradation activity but have significant NO photodestruction capability, both in UV and visible regions, while standard Degussa P-25 is incapable in destroying NO in the visible region The mid-gap levels that these N and Fe-N-doped TiO2 consist may cause this discrepancy in their photocatalytic activities.  相似文献   

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