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过程工程学报 ›› 2018, Vol. 18 ›› Issue (6): 1293-1301.DOI: 10.12034/j.issn.1009-606X.218135

• 过程与工艺 • 上一篇    下一篇

Ti/Zr助剂掺杂VPO催化正丁烷选择性氧化制顺酐

李雅婧1,2, 南琳琳2, 贺 滨2, 刘瑞霞2*, 廖丹葵1*   

  1. 1. 广西大学化学化工学院,广西 南宁 530004 2. 中国科学院过程工程研究所绿色过程与工程重点实验室,离子液体清洁过程北京市重点实验室,多相复杂系统国家重点实验室,北京 100190
  • 收稿日期:2018-02-19 修回日期:2018-04-28 出版日期:2018-12-22 发布日期:2018-12-19
  • 通讯作者: 廖丹葵 biochemical509@163.com
  • 基金资助:
    碳-氧键构建制酯/酐类化学品的纳米催化新技术;中国科学院重点部署项目

Selective oxidation of n-butane to maleic anhydride catalyzed by Ti/Zr modified VPO

Yajing LI1, Linlin NAN2, Bin HE2, Ruixia LIU2*, Dankui LIAO1*   

  1. 1. School of Chemistry & Chemical Engineering, Guangxi University, Nanning, Guangxi 530004, China 2. Key Lab of Green Process and Engineering, Beijing Key Laboratory of Ionic Liquids Clean Process, State Key Lab of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2018-02-19 Revised:2018-04-28 Online:2018-12-22 Published:2018-12-19
  • Contact: LIAO Dan-kui biochemical509@163.com

摘要: 采用有机相法制备钒磷氧(VPO)催化剂,并在合成过程中加入Ti/Zr助剂,使用微型固定床反应器评价其催化正丁烷选择性氧化制顺酐的性能,考察了不同助剂元素及其化合物形式和添加量对催化剂性能的影响,分析了添加助剂对催化剂晶相及微观形貌的影响. 结果表明,加入助剂未改变催化剂的晶相结构,但促进了活性相(VO)2P2O7生成,且使反应后催化剂微观形貌发生改变,片层更破碎,活性相暴露,同时生成了利于反应的微量V5+;助剂金属Ti和Zr与V元素间的相互作用对催化剂表面P浓度及V价态都有一定影响;与不加助剂的VPO催化剂相比,相同反应条件下,Ti/Zr助剂修饰的VPO催化性能显著提高,摩尔比Zr/V为1.5%的Zr(NO3)4为助剂的催化剂的催化性能最佳,稳定状态下正丁烷的转化率高达99.1%,顺酐收率为54.4%.

关键词: VPO催化剂, 助剂, 正丁烷选择性氧化, 顺酐

Abstract: Maleic anhydride (MA) is a kind of important organic chemical raw materials and fine chemical products, has a wide application and strong market demand, while vanadium phosphorus oxide (VPO) catalyst is the most effective catalyst for n-butane selective oxidation to maleic anhydride. However, the catalysts suffer from the shorts of low activity, selectivity. Many efforts had been devoted to improve their catalytic performance. Among them, modification with metal promoters was considered as an effective method. In the present work, Ti/Zr promoter was selected as additive to modify VPO during its preparation with organic medium method. Their catalytic performance for selective oxidation of n-butane to produce maleic anhydride were tested in fixed-bed reactor at 420℃ with gas hourly space velocity of 2000 h?1. The effects of metal element, precursor and additive amount of promoters on the catalytic performance were investigated in details. The change of phase structure, the morphology as well as electronic properties of catalysts were characterized by X-ray diffraction, Raman, SEM, XPS. Compared with VPO catalyst without promoter, the VPO catalysts modified with Ti/Zr promoter effectively improved the catalytic performance for n-butane conversion rate and maleic anhydride selectivity. Especially, for the VPO catalyst promoted by Zr(NO3)4 doping with molar ratio of Zr to V of 1.5%, the conversion rate of n-butane can reached 99.1% and the yield to maleic anhydride was 54.4%. The promoters did not change the phase structure of the catalyst, but promoted the formation of the active phase (VO)2P2O7 and change the morphology of the catalyst, forming smaller size of VPO sheet and correspondingly exposing more active sites, furthermore, the interaction between the promoters and V has great effects on the concentration of P and the valence of V on the surface of VPO catalyst. In addition, the chemical compound formation of promoter elements had an important influence on the performance of VPO catalyst. When Zr(NO3)4 was used as the promoter, the conversion of n-butane was much higher than that with the promoter of ZrO2. Further, the promoter elements also had important influence on the performance of VPO catalyst. Compared with ZrO2, the catalysts modified by TiO2 showed better catalytic performance because Ti can better enter the lattice of catalyst instead of V.

Key words: VPO catalyst, promoter, Selective oxidation of n-butane, maleic anhydride