Effect of the method of preparation of a Nd2O3-MgO catalyst on its efficiency in the reaction of oxidative coupling of methane

It is shown that the decomposition of a mixture of nitrates or coprecipitated carbonates or hydroxides of Mg and Nd form catalysts manifesting similar catalytic properties, while the catalyst obtained by impregnation is more active but much less selective. The mechanism of formation of the catalytically active phase and the nature of the active sites are discussed.     

Sintering of Pt/Al2O3 reforming catalysts: EXAFS study of the behavior of metal particles under oxidizing atmosphere

The effect of an oxidative atmosphere (300 °C) is studied on fresh and sintered unchlorinated naphtha reforming catalysts containing 0.6–1% Pt. The TPR profiles show that only one species is formed using our experimental conditions, regardless of the mean crystallite size of the metal particles. The structural information supplied by EXAFS compared with cuboctahedral particle modeling, implies that such species is a surface platinum oxide, the structure of which is close to that of PtO₂, but largely distorted. This is true whether the catalyst is sintered or not.     

不同载体钯催化剂的结构表征及其在笼形叔胺脱N-苄基上的应用

以γ Al2O3、木质活性炭、煤质活性炭为载体,以氯化钯为前体制备了Pd(OH)2/Al2O3、Pd(OH)2/C催化剂,并用X射线衍射、透射电镜和X射线光电子能谱等技术对这些催化剂进行了结构表征。以六苄基六氮杂异伍兹烷(HBIW)的脱苄反应为例,研究了不同载体Pd(OH)2催化剂对笼形叔胺N 苄基脱苄反应的活性,分析了影响催化剂活性的各种因素。实验结果表明,当催化剂用量为HBIW质量的0 2%(以Pd计)时,氢解产品四乙酰基二苄基六氮杂异伍兹烷(TADBIW)的收率可达88%,其中以煤质活性炭为载体的催化剂已用于HBIW氢解脱苄的20kg级放大实验,TADBIW产品收率为82%。     

活性炭纤维制备双电层电容器

研究了不同材料、比表面积和电解液对比电容的影响,不同比表面积,电解液对循环充电稳定性的影响。结果表明,作为制备双电层电容器的电极材料,活性炭纤维明显好于活性炭,同样基质的活性炭纤维,比表面积大的,比电容不一定大。     

Cs2.5H0.5PW12O40/SiO2催化剂上叔戊烯与甲醇的醚化

摘要：制备了硅胶负载的Cs2．5H0．5PW12O40／SiO2催化剂,并用于叔戊烯与甲醇的醚化反应。考察了催化剂制备方法和工艺条件对叔戊烯转化率的影响。研究结果表明,以低钠硅胶为载体,在负载量40％、焙烧温度400℃条件下制备的Cs2．5H0．5PW12O40／SiO2催化剂具有较高的催化活性。在反应温度为80℃、压力为1．0MPa、n(甲醇)／n(叔戊烯)为1．1、LHSV为1h^-1的条件下,叔戊烯的转化率为68．57％.Cs2．5H0．5PW12O40／SiO2催化剂对于叔戊烯与甲醇的醚化反应具有良好的活性与选择性,是一种理想的叔戊烯与甲醇的醚化反应的催化剂。     

超临界氨合成

Ammonia synthesis at supercritical conditions was first studied over iron and active carbonsupported ruthenium catalysts in a fixed-bed reactor. The influences of 15 kinds of different supercritical media, such as alkanes of C7-C13, 1, 2, 3, 4-tetrahydronaphthalene, cis-decalin, o-xylene,ethylbenzene, quinolin, n-hexane and aniline etc. and reaction conditions (catalyst, temperature, space velocity, particial pressure of media) on ammonia at supercritical condition were investigated.Supercritical medium was decomposed under reaction conditions over Fe and Ru/AC catalysts. The decomposition products deactivated the catalysts. Alkane decomposed the least, and the rate of deactivation was the slowest. Therefore alklane was a relatively good medium. The decomposion of supercritical medium was the key for the deactivation of catalysts. Another important reason for the decrease of ammonia concentration was that the effective pressure of syngas decreased because of the presence of supercritical media. The active temperature of catalyst was the decisive factor in supercritical ammonia synthesis. Supercritical catalytic reaction was viable only at a lower temperature. Ammonia ynthesis at supercritical conditions is possible if a catalyst with active temperature lower than 573 K could e developed and the decomposition of supercritical media could be prevented.     

活性炭负载镧催化合成乙酸丁酯的研究

研究活性炭负载镧为酯化催化剂合成乙酸丁酯。探讨了负载温度、原料比例、催化剂用量、反应时间、催化剂重复使用效果等因素对酯化率的影响,确定了较佳的工艺条件,催化剂为0．8g,醇酸比为(2—2．5)：1,反应时间为2h,最高酯化率可达98．89％。     

熔融结晶及其耦合技术研究的进展

介绍逐步冻凝熔融结晶过程和悬浮熔融结晶过程以及各自特点,综述了近年来新型熔融结晶技术与设备的应用研究进展;着重介绍了耦合技术在熔融结晶过程中的应用研究动态;最后展望了熔融结晶技术与设备的发展趋势与方向。     

催化剂对沥青氧化聚合的影响

在300℃、空气条件下用硝酸钾、对甲苯磺酸两种催化剂对沥青进行氧化处理,通过软化点、甲苯不溶物含量、元素分析、红外光谱分析以及热重分析检测发现催化剂对软化点、组成、分子结构有显著影响。沥青经催化氧化后甲苯不溶物含量增加,高分子组分比例增加,低分子组比例减少,软化点升高,升高幅度达40%～100%,H/C原子比减少,苯环上的氢及侧链减少,芳环缩合程度增加。热失重表明催化剂的存在加快了沥青的氧化分解,分子侧链的断裂,从而加快氧化聚合速度。     

全球催化剂工业动向

介绍了在全球范围内催化剂工业的现状,包括市场需求及经营形势。由于美国及其他国家环保法规日趋严格迫使炼油工业采用清洁燃料催化剂,导致炼油催化剂需求量上升,聚烯烃催化剂工业获得较大发展,炼油催化剂技术推陈出新。特种化学品产品催化剂和精细化工领域的催化剂工业将面临挑战。