高等学校化学学报 ›› 2018, Vol. 39 ›› Issue (3): 497-505.doi: 10.7503/cjcu20170668

• 物理化学 • 上一篇    下一篇

TMPDO及4-NOH-TMPD吸附对H2O2/HTS催化体系自由基生成的影响及应用

陈洁1,2, 赵迎宪1, 张永明3, 张胜建1(), 严山1, 赵红1, 李显明3, 应丽艳1   

  1. 1. 浙江大学宁波理工学院, 宁波 315100
    2. 浙江大学化学与生物工程学院, 杭州 310027
    3. 浙江中高压催化加氢工程研究中心, 台州 317300
  • 收稿日期:2017-10-11 出版日期:2018-03-10 发布日期:2018-01-13
  • 作者简介:联系人简介: 张胜建, 男, 教授, 主要从事催化、 绿色化工方面的研究. E-mail:zsj@nit.zju.edu.cn
  • 基金资助:
    浙江省自然科学基金(批准号: LY13B030003)资助

Effects of TMPDO and 4-NOH-TMPD on H2O2/HTS Catalytic System for Free Radicals Generation and Its Application

CHEN Jie1,2, ZHAO Yingxian1, ZHANG Yongming3, ZHANG Shengjian1,*(), YAN Shan1, ZHAO Hong1, LI Xianming3, YING Liyan1   

  1. 1.Ningbo Institute of Technology, Zhejiang University, Ningbo 315100, China
    2. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
    3. Zhejiang Middle-high Pressure Catalytic Hydrogenation Engineering Research Center, Taizhou 317300, China
  • Received:2017-10-11 Online:2018-03-10 Published:2018-01-13
  • Contact: ZHANG Shengjian E-mail:zsj@nit.zju.edu.cn
  • Supported by:
    † Supported by the Natural Science Foundation of Zhejiang Province, China(No.LY13B030003)

摘要:

采用电子顺磁共振(EPR)技术考察了中空钛硅分子筛(HTS)吸附2,2,6,6-四甲基哌啶-4-酮(TMPDO)及2,2,6,6-四甲基哌啶-4-酮肟(4-NOH-TMPD)后, 在H2O2存在下催化剂表面和液相中自由基生成的变化. 结果表明, 在HTS被4-NOH-TMPD吸附改性后, 原HTS/H2O2体系溶液中存在的·OH信号强度明显下降, 而·自由基信号强度增加28倍, 且催化剂表面TiOO-·信号强度增加了1倍多. 通过Simfonia软件模拟分析发现, HTS/H2O2/4-NOH-TMPD体系中主要生成了结构为TiOO-·(η2)…4-NOH-TMPD的自由基. 4-NOH-TMPD在HTS/H2O2中由双位吸附产生的对TiOOH的稳定作用是导致上述变化的根本原因. 进一步研究发现, HTS/H2O2体系中加入4-NOH-TMPD后, 催化剂表面的自由基信号基本消失, 而液相中丙酮肟与Ti—OO-·或·自由基作用生成了2种新自由基, 使HTS/H2O2/4-NOH-TMPD体系具有催化丙酮肟氨氧化偶联生成2,3-二甲基-2,3-二硝基丁烷(DMNB)的活性.

关键词: 电子顺磁共振, 中空钛硅分子筛, 2,2,6,6-四甲基哌啶-4-酮肟, 丙酮肟

Abstract:

EPR technique was used to investigate the formation and variation of free radicals on the catalyst and in the liquid phase after adsorption of 2,2,6,6-tetramethyl-piperdin-4-one(TMPDO) and 2,2,6,6-tetramethyl-piperdin-4-one oxime(4-NOH-TMPD) over hollow titanium silicalite(HTS) zeolite in the presence of H2O2. The results showed that the EPR signal of HO· in the HTS/H2O2 system was significantly decreased after 4-NOH-TMPD adsorbed on HTS, while the signal intensity of · free radical increased by 28 times and that of TiOO-· increased by more than double. Moreover, Simifonia software simulation indicated that the free radicals of TiOO-·(η2)…4-NOH-TMPD were formed in the HTS/H2O2/4-NOH-TMPD system, and the stabilization of the double-site adsorption of 4-NOH-TMPD in HTS/H2O2 to TiOOH was the fundamental cause for the above changes. Furthermore, it was found that as 4-NOH-TMPD added into the HTS/H2O2 system, the signal of free radicals on the catalyst almost disappeared while two new free radicals were formed due to the interaction between acetone oxime in liquid phase and Ti—OO-· or · free radicals, giving HTS/H2O2/4-NOH-TMP system with the catalytic activity for the oxidative coupling of acetone oxime to form 2,3-dimethyl-2,3-dinitrobutane(DMNB).

Key words: Electron paramagnetic resonance(EPR), Hollow titanium silicalite(HTS), 2,2,6,6-Tetrame-thyl-piperdin-4-one oxime(4-NOH-TMPD), Acetone oxime

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