Ultra-deep oxidative desulfurization of diesel fuel by the Mo/Al2O3-H2O2 system:: The effect of system parameters on catalytic activity
Ultra-deep oxidative desulfurization of diesel fuel by the Mo/Al2O3-H2O2 system:: The effect of system parameters on catalytic activity
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DOI：
10.1016/j.apcata.2007.10.024
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发表时间：
2008-01-01
影响因子：
5.5
通讯作者：
Jimenez-Cruz, Federico
中科院分区：
文献类型：
--
作者：
Garcia-Gutierrez, Jose Luis;Fuentes, Gustavo A.;Jimenez-Cruz, Federico
本文介绍了Mo/γ-Al_2O_3催化剂的研制结果及其在以过氧化氢为氧化剂的柴油氧化脱硫过程中的评价。以几种钼前驱体和不同酸度的氧化铝为原料，通过平衡吸附制备了催化剂。用拉曼光谱对其进行了表征。考察了反应时间、反应温度、溶剂性质、溶剂和双氧水浓度、催化剂中钼和磷酸盐含量等因素对反应的影响。结果表明，催化剂的脱硫活性主要取决于催化剂载体上七钼酸根和八钼酸根物种的存在以及非质子溶剂的使用。同样，磷酸盐的存在也显著提高了脱硫率。这样，在333K和大气压下，柴油中的硫含量就有可能从320左右降到10ppmw以下。此外，在所得结果的基础上，对该反应的机理提出了建议，认为这是硫原子对七钼酸根和八钼酸根过氧物种的亲核攻击所致的氧化机理，但涉及单重态氧存在的机理可被摒弃。(C)2007 Elsevier B.V.保留所有权利。
This work presents the results obtained in the development of Mo/gamma-Al2O3 catalysts and their evaluation in the oxidative desulfurization (OD) process of diesel fuel using hydrogen peroxide as the oxidizing reagent. The catalysts were prepared by equilibrium adsorption using several molybdenum precursors and aluminas with different acidity values. They were characterized by Raman spectroscopy. The effect of the reaction time, reaction temperature, nature of solvent, concentration of solvent and hydrogen peroxide, content of molybdenum and phosphate in the catalysts were investigated. The results showed that the activity for sulfur elimination depends mainly on the presence of hepta- and octamolybdates species on the catalyst support and the use of a polar aprotic solvent. Likewise, the presence of phosphate markedly increases the sulfur elimination. In this way, it is possible to reduce sulfur level in diesel fuel from about 320 to less than 10 ppmw at 333 K and atmospheric pressure. Additionally, on the basis of the results obtained a mechanistic proposal for this reaction is described, as an oxidation mechanism by nucleophilic attack of the sulfur atom on peroxo species of hepta- and octamolybdates, but a mechanism involving the singlet oxygen presence can be discarded. (c) 2007 Elsevier B.V. All rights reserved.