CIESC Journal ›› 2015, Vol. 66 ›› Issue (12): 4843-4849.DOI: 10.11949/j.issn.0438-1157.20151013

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Production of 2-chloro-5-trifluoromethylpyridine and 3-trifluoromethylpyridine

DONG Qingqing1, YU Wanjin2, HU Meng1, LIN Shengda2, LIU Wucan2, ZHANG Jianjun2, CHENG Dangguo1, CHEN Fengqiu1   

  1. 1 College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China;
    2 Zhejiang Research Institute of Chemical Industry, ODS Substitutes National Engineering Research Center, Zhejiang Key Laboratory of New Chemical Materials, Hangzhou 310023, Zhejiang, China
  • Received:2015-06-29 Revised:2015-09-09 Online:2015-12-05 Published:2015-12-05
  • Supported by:

    supported by the Postdoctor Foundation of Zhejiang (BSH1402061).

2-氯-5-三氟甲基吡啶和3-三氟甲基吡啶的制备

董青青1, 于万金2, 胡猛1, 林胜达2, 刘武灿2, 张建君2, 程党国1, 陈丰秋1   

  1. 1 浙江大学化学工程与生物工程学院, 浙江 杭州 310027;
    2 浙江省化工研究院, 国家ODS替代品工程技术研究中心, 浙江省化工新材料重点实验室, 浙江 杭州 310023
  • 通讯作者: 陈丰秋
  • 基金资助:

    浙江省博士后科研择优资助项目(BSH1402061)。

Abstract:

2-Chloro-5-trifluoromethylpyridine and 3-trifluoromethylpyridine are produced by β-picoline reacting with chlorine and hydrogen fluoride in a fluidized-bed reactor. The total yield of 2-chloro-5- trifluoromethylpyridine and 3-trifluoromethylpyridine reaches 66.6% over the CrO-Al catalyst at a space velocity of 288 h-1 and temperature of 300℃. The reactivity of the deactivated catalysts is recovered after regeneration at 350℃ with mixed gas of nitrogen and air at volume ratio of 1:1. The total yield is around 66% with regenerated catalysts under the condition of 288 h-1 and 300℃. According to the reaction result, the mechanism of one-step chlorofluorination reaction is proposed, dehydrochlorination-condensation of intermediate products accounted for coking. The results of BET, TG and NH3-TPD characterizations indicate that the deactivation of the catalysts is caused by the carbonaceous by-products which cover the surface and pores of the catalyst.

Key words: 2-chloro-5-trifluoromethylpyridine, 3-trifluoromethylpyridine, β-picoline, fluidized-bed, catalyst, reactivity, regeneration

摘要:

研究了以3-甲基吡啶、氟化氢和氯气为原料在流化床反应器中一步法气相氯氟化反应制备2-氯-5-三氟甲基吡啶和3-三氟甲基吡啶的工艺,并对催化剂进行了筛选和考评,发现CrO-Al、CrCl-Al的活性较佳。以CrO-Al为催化剂,空速为288 h-1,温度为300℃时,2-氯-5-三氟甲基吡啶和3-三氟甲基吡啶的总收率最高,为66.6%,且失活催化剂在350℃,氮气和空气的体积比为1:1的混合气体下再生后,其催化活性基本可以恢复,2-氯-5-三氟甲基吡啶和3-三氟甲基吡啶的总收率均保持在66%左右。根据实验结果提出了反应机理和结焦机理。对催化剂进行了BET、TG和NH3-TPD表征,发现催化剂失活的主要原因是积炭覆盖了催化剂表面以及孔道,使催化剂强酸中心大量减少所致。

关键词: 3-甲基吡啶, 2-氯5-三氟甲基吡啶, 3-三氟甲基吡啶, 流化床, 催化剂, 活性, 再生

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