Co-Mo-K/Al_2O_3水煤气变换催化剂的失硫与活性

Co-Mo 系催化剂由于其优越的耐硫性能和对水煤气变换反应的高活性,因此在制氢工业中日益得到重视。已知 Co-Mo-K/Al_2O_3催化剂是一种优良的水煤气变换催化剂,该催化剂在使用前须经硫化。实际上催化剂在反应时

乙醇氧化酯化反应中Sb-Mo二元氧化物催化剂的复合效果

从活性试验、比表面测定、结构分析、还原度测定及程序升温还原等多方面考察了 Sb—Mo二元氧化物体系与单独氧化物 MoO_3、Sb_2O_4的特性,认为与单独氧化物相比,在标题反应中 Sb-Mo二元氧化物的高活性与其比表面的增大有关,乙酸乙酯选择性的提高是由于在反应气氛下催化剂内生成了新的活性相。显示出较高氧化酯化选择性的工作状态,催化剂处于某种程度被还原的状态。这种状态下的催化剂体相氧比较活泼。

MEASUREMENT OF SPONTANEOUS EMISSION BRANCHING RATIOS IN MO(I) TRANSITIONS BY LASER-INDUCED SENSITIZED FLUORESCENCE

I. TNTRODUCTIONThe emission spectroscopic method is usually used to measure spontaneous emission branching ratios. As emission spectra cannot be detected in atomic beams, the laser-induced fluorescence or ion detection method is often used. When the fluorescence method is used to measure branching ratios, it is usually necessary to detect

甲醇氨氧化合成氢氰酸Fe-Mo氧化物催化剂的研究

利用固定床反应器,研究了 Fe-Mo 氧化物/载体催化剂对甲醇氨氧化制氢氰酸的催化性能,考察了催化剂组成和反应条件(如温度)对催化活性的影响。氢氰酸的单程收率可达94%。发现催化剂的活性与表面酸性有关。活性相的结构为 Fe_2(MoO_4)_3。

Extraction behavior of Mo and W as homologs of Sg with α-benzoinoxime

Solvent extraction of molybdenum and tungsten as homologues of Sg with a-benzoinoxime from HCl solutions has been investigated. The extraction equilibration was achieved at 20s for Mo and W. Molybdenum was almost quantitatively extracted from 0.001 to 4M HCl solutions, and the extraction yields decreased at higher and lower acid concentrations due to the formation of anionic oxychloride complex and anionic species MO42-, respectively. The extraction yield of W was lower than that of Mo during the whole range of acid concentration. The composition of the extracted species was determined by using the slope method in present experiment. The elemental analysis, IR and 1H NMR spectra of the extracted species suggest that the extracted complex contain one MoO22+or WO22+ groups bonded with two a-benzoinoxime molecules.

地质样品中Mo同位素测定的前处理方法研究

通过对地质样品中Mo同位素测试前的处理方法的比较，对传统的阴、阳离子树脂交换法进行了改进研究。经改进后的方法实用范围较宽，Mo的回收率达到97．49％±0．27％，Mo同位素质谱分析过程中可能的同重干扰元素Zr、Fe、Mn等的去除效果理想，其它金属元素的去除效果也较理想，且在阴离子交换柱洗脱Mo的过程中总计约需的提取液（盐酸和硝酸）体积只有75mL，只需文献报道用量的45％，从而减少了试剂对样品，特别是对低含量地质样品可能带来的潜在污染.

Mo稳定同位素研究进展

随着表面热离子质谱（TIMS）和多接收器电感耦合等离子体质谱（MC-ICP-MS）的广泛应用以及同位素分析方法的改进,近10年来非传统稳定同位素（Cu、Zn、Fe、Se、Mo、Cr、Hg等）的研究得到迅速发展。其中,由于Mo同位素的分馏明显受氧化还原条件的控制,使其在指示古环境及古气候的变化方面有独特的地球化学指示意义。同时,Mo同位素在指示成矿物质来源和海洋Mo循环等方面也取得较大成果。因此,Mo同位素地球化学研究已成为国际地学领域的一个前沿和热点。本文综合前人的研究成果,结合近期自己的工作,论述了Mo同位素地球化学研究领域的一些重要进展,详细介绍了Mo同位素的化学分离、提纯和质谱分析技术,并对其应用前景进行了展望.

The chemical nature of carbonaceous deposits and their role in methane dehydro-aromatization on Mo/MCM-22 catalysts

Various carbonaceous deposits are formed during the course of methane dehydro-aromatization (MDA) under non-oxidative conditions on Mo/MCM-22 catalysts. These carbon species were investigated by various temperature-programmed techniques such as TPH and TPCO2, combining with TPO and TGA results in order to reveal their chemical nature and determine their amounts. The TPO profiles recorded from coked Mo/MCM-22 catalysts show two temperature peaks: one at about 756 K and the other at about 876 K. The coke amounts related to these two peaks were determined on the basis of the corresponding corrected and deconvoluted TPO profiles, combining with the TGA profiles concerned.