助剂对一步法制备钒磷氧催化剂性能影响研究

发布时间：2018-03-02 00:17

本文关键词： 钒磷氧催化剂助剂正丁烷催化性能　出处：《西南石油大学》2011年硕士论文　论文类型：学位论文

【摘要】：本文以异丁醇和苯甲醇同时作为溶剂和还原剂,以多聚磷酸为替代磷源,采用一步法制备钒磷氧(VPO)催化剂前驱体VOHPO4·0.5H2O。通过实验与多种表征手段系统考察了掺杂铋、铌助剂对一步法制备钒磷氧催化剂催化性能的影响。掺杂铋助剂系列的VPO催化剂其微观形貌呈大量片层状晶体紧密堆积成规整的玫瑰花苞状,花苞的直径约5-7μm,花苞片层的厚度约70-80nm。Bi原子取代(VO)2P2O7中的V原子,形成固溶体,降低了催化剂表面的V原子含量,加速气相O2在催化剂表面的吸附。制备得到的VPO催化剂具有较高的催化性能。在原子比为V:P:Bi =1:1.1:0.01时(催化剂A3),催化剂的顺酐摩尔收率为51.9%,正丁烷的转化率为75.3%,顺酐的选择性为69%。掺杂铌助剂系列的VPO催化剂,在铌助剂作用下,VPO催化剂的微观形貌发生了改变,活化后的VPO催化剂存在两种聚集:一种是大量片层状晶体紧密堆积略成玫瑰花苞状,另一种是少量破碎状晶体散乱分布。通过对掺杂助剂的VPO催化剂性能评价和理化分析,发现添加助剂的钒磷氧催化剂均不同程度的提高了正丁烷的转化率和选择性,增大了催化剂的比表面积,调变了催化剂的物相组成,改变了催化剂的微观形貌。
[Abstract]:In this paper, using isobutanol and benzyl alcohol as solvent and reducing agent, using polyphosphoric acid as substitute for phosphorus, the precursor of vanadium phosphate oxide (VPO) catalyst, VOHPO4 路0.5H2O, was prepared by one-step method. The doped bismuth was systematically investigated by means of experiments and various means of characterization. The effect of niobium promoters on the catalytic performance of vanadium phosphorous oxide catalysts prepared by one step method. The microstructure of the VPO catalysts doped with bismuth promoters was closely stacked in a large number of lamellar crystals to form a regular rose bud. The diameter of the bud is about 5-7 渭 m, and the thickness of the flake layer is about 70-80nm.Bi instead of the V atom in VO _ 2P _ 2O _ 7 to form a solid solution, which reduces the V atom content on the surface of the catalyst. The prepared VPO catalyst has high catalytic performance. The molar yield of maleic anhydride is 51.9%, the conversion of n-butane is 75.3%, and the maleic anhydride is obtained at the atomic ratio of V: P: Bi 1: 1.1: 0.01. The selectivity of VPO catalyst doped with niobium auxiliaries is 69. Under the action of niobium promoter, the morphology of VPO catalyst changed, and there were two kinds of aggregation in activated VPO catalyst: one was that a large number of lamellar crystals were tightly stacked into a rose bud. The other is the scattered distribution of a small amount of broken crystals. Through the performance evaluation and physicochemical analysis of the doped VPO catalyst, it is found that the vanadium phosphorous oxide catalyst with the additive increases the conversion and selectivity of n-butane in varying degrees. The specific surface area of the catalyst was increased, the phase composition of the catalyst was adjusted, and the microstructure of the catalyst was changed.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：O643.36

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