Reduced nickel hydromolybdate catalysts: hydrogen chemisorption and activity in benzene hydrogenation
Reduced nickel hydromolybdate catalysts: hydrogen chemisorption and activity in benzene hydrogenation
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DOI：
10.1016/0021-9517(85)90349-5
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发表时间：
1985-02
影响因子：
7.3
通讯作者：
M. Astier;M. Lacroix;S. Teichner
中科院分区：
文献类型：
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作者：
M. Astier;M. Lacroix;S. Teichner
前面已经证明(1)，合成的水合钼酸镍‘ Ni0, Mo03, 2hz0 ’在250℃以上的温度下被氢还原，在100℃时苯加氢成环己烷的催化剂具有活性。初始二元化合物中的镍离子不仅被还原成金属镍的状态，其x射线图的缺失也证明了这一点。第二组分（氧化钼）也被还原并与镍生成金属间化合物MoNi，(2)。无水钼酸镍（NiMo04）在相当低的温度下（略高于2SO 'C）不会发生这种还原，因为它需要500-600℃的温度范围(3)。对于三元HDS催化剂，y-A120j上的NiO (3%), MoOj(10%)，在500℃下使用前煅烧，因此含有Ni MOO，在350℃下还原甚至不会产生任何显著的MoOz。与Moo3(4)相比，这种氧化物的后续硫化是困难的，并且在硫化前低于350℃的催化剂在HDS中具有活性，而在较高温度下的还原会损害催化活性。由水合钼酸镍低温还原形成的金属间化合物mo &，其初始表面积（236 m’/g）仅因还原（230 m2/g）而减少很少，是一种值得开发的具有催化活性的化合物。事实上，最近人们发现各种金属间化合物作为各种反应的催化剂具有极大的兴趣。其中RE、Ni、（RE=稀土或镧）金属间化合物在CO加氢、甲苯脱烷基和乙烷氢解中具有活性(5)，而其他金属间化合物-
It has been shown previously (I) that the reduction of a synthesized hydrated nickel molybdate ‘Ni0, Mo03, 2Hz0’by hydrogen at a temperature above 250 C leads to a catalyst active in hydrogenation of benzene to cyclohexane at 100 C. The nickel ions in the initial binary compound are not reduced merely into the state of metallic nickel, as evidenced by the fact that its X-ray pattern is absent. The second component (molybdenum oxide) is also reduced and gives with nickel the intermetallic compound MoNi,(2). This reduction at a fairly low temperature (somewhat above 2SO’C) is not encountered with the anhydrous nickel molybdate (NiMo04), for which a temperature range of 500-600 C is required (3). In the case of ternary HDS catalysts, NiO (3%), MoOj (10%) on y-A120j, calcined before use at 500 C and therefore containing Ni MOO,, the reduction at 350 C does not even produce MoOz to any significant extent. The subsequent sulfidation of this oxide is difficult, in contrast to Moo3 (4), and the catalysts reduced below 350 C before sulfidation were active in HDS whereas reduction at higher temperatures impaired the catalytic activity.The intermetallic MoN& formed by lowtemperature reduction of hydrated nickel molybdate, where the initial surface area (236 m’/g) drops only very little by reduction (230 m2/g) is an interesting compound to exploit for catalytic activity. Indeed, recently various intermetallics have been found to be of great interest as catalysts for various reactions. Among them are RE, Ni,(RE= rare earth or lanthanum) intermetallics which are active in CO hydrogenation, toluene dealkylation, and ethane hydrogenolysis (5), while other intermetal-