多孔分子筛SBA-15负载多核钼硫簇合物的催化表征及加氢脱硫的探索

发布时间：2018-01-21 10:00

  本文关键词： 钼硫簇合物 钼氧硫簇合物 多孔分子筛 负载 加氢脱硫　出处：《安徽工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：多核钼硫簇的特殊结构使其具有丰富的活性硫原子,如稳定的桥硫原子和活性相对较高的端硫原子,从而使得多核钼硫簇合物在加氢脱硫和电化学析氢等方面具有广泛的应用。本论文中共制备了5个多核钼硫簇合物((Et4N)2[Mo3S9]、(HNEt3)2[Mo3S7(mba)3]、(NH4)2[Mo3S13]·nH2O、(NH4)2[Mo2S12]·2H2O、(Et4N)2[Mo2S10])和6个多核钼氧硫簇合物((Me4N)2[Mo2S6O2]、Cs2[Mo4S4O4(C4O6)2]、(Me4N)4[Mo6S14O6]、K3(Me4N)[Mo6S6O6(OH)4(C2O4)3]、Cs2[Mo8S8O8(OH)10]、(Me4N)[Mo9S8O12])。为了避免均相催化中存在的稳定性差,重复利用率低以及难回收等问题,采用浸渍法将上述多核钼硫簇合物和钼氧硫簇合物负载到分子筛SBA-15上得到负载型催化剂。通过红外光谱(IR)、X-射线衍射(XRD)、透射电镜(TEM)等方法对负载型催化剂的结构进行表征和分析。结果表明:两种系列负载催化剂都很好地保持了分子筛的介孔结构性质,多核钼硫簇合物和钼氧硫簇合物均匀地分散在分子筛SBA-15上。以噻吩作为催化底物,系统地考查了系列负载型多核钼硫簇合物催化剂在不同条件下的加氢脱硫催化效果。结果表明:在280℃、18小时、1.0 MPa氢气压力下两类负载型催化剂能够表现出较好的催化效果,而且具有较好的多次循环的绿色催化效果,其中硫单元S22-个数较多的簇合物(NH4)2[Mo3S13]·nH2O、(NH4)2[Mo2S12]·2H2O和(Me4N)4Mo6S14O6表现出相对较好的催化效果。机理分析表明:多核钼硫簇合物中S22-单元对加氢脱硫反应的催化活性具有促进作用,硫单元S22-在氢气作用下生成高活性的加氢基团-SH,氢原子从-SH基团上转移到噻吩的碳原子上生成四氢噻吩,完成加氢过程。簇合物上的S在氢气作用下以H2S的形式脱去产生空位,与此同时四氢噻吩上的硫进攻此空位并与Mo结合完成脱硫的步骤。
[Abstract]:The special structure of the polynuclear molybdenum sulfur cluster makes it rich in active sulfur atoms, such as stable bridged sulfur atoms and relatively high active terminal sulfur atoms. Therefore, the polynuclear molybdenum sulfur cluster has been widely used in hydrodesulfurization and electrochemical hydrogen evolution. [Mo3S9. [Mo3S7(mba)3. [Mo3S13] 路NH _ 4H _ 2O _ 2. [Mo2S12] 路2H _ 2O _ 4N _ 2. [(Mo2S10) and 6 polynuclear molybdenum oxysulfide clusters. [Mo2S6O2] ,Cs2. [Mo4S4O4(C4O6)2. [Mo6S14O6). [Mo6S6O6(OH)4(C2O4)3] ,Cs2. [Mo8S8O8(OH)10 (Me4N). [In order to avoid the problems of poor stability, low reuse rate and difficult recovery in homogeneous catalysis, Mo9S8O12]. The polynuclear molybdenum sulfur cluster and molybdenum oxide sulfur cluster were loaded on the molecular sieve SBA-15 by impregnation method to obtain the supported catalyst. The structure of the supported catalyst was characterized and analyzed by TEM and TEM. The results showed that the mesoporous structure of the molecular sieve was well maintained by the two series of supported catalysts. The polynuclear molybdenum sulfur cluster and the molybdenum oxide sulfur cluster were uniformly dispersed on the molecular sieve SBA-15 with thiophene as the catalyst substrate. The catalytic effects of a series of supported polynuclear molybdenum sulfur cluster catalysts on hydrodesulfurization under different conditions were systematically investigated. The results showed that the catalyst was at 280 鈩，

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