CIESC Journal ›› 2016, Vol. 67 ›› Issue (5): 1884-1891.DOI: 10.11949/j.issn.0438-1157.20151260

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Synthesis of 2-ethyl-2-hexenal via n-butanal self-condensation catalyzed by La-Al2O3

LIU Xiaohong, WANG Yi, AN Hualiang, ZHAO Xinqiang, WANG Yanji   

  1. Hebei Provincial Key Laboratory of Green Chemical Technology & High Efficiency Energy Saving, School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin 300130, China
  • Received:2015-08-04 Revised:2016-02-01 Online:2016-05-05 Published:2016-05-05
  • Supported by:

    supported by the National Natural Science Foundation of China (21476058, 21506046, 21236001).

La-Al2O3催化正丁醛自缩合合成辛烯醛反应

刘肖红, 王毅, 安华良, 赵新强, 王延吉   

  1. 河北工业大学化工学院, 绿色化工与高效节能河北省重点实验室, 天津 300130
  • 通讯作者: 赵新强
  • 基金资助:

    国家自然科学基金项目(21476058,21506046,21236001)。

Abstract:

2-Ethylhexanol is a kind of important plasticizer alcohols. n-Butanal self-condensation to 2-ethyl-2-hexenal is one of the important processes for industrial production of 2-ethylhexanol. In order to overcome the shortcomings such as equipment corrosion, environmental pollution and high production cost in the present industrial n-butanal self-condensation reaction using alkali aqueous catalyst, the La-modified γ-Al2O3 catalyst (La-Al2O3) was adopted to catalyze n-butanal self-condensation reaction. Firstly, the influence of different preparation methods and conditions on the La-Al2O3 catalytic activity was studied. The results showed that the catalytic activity of La-Al2O3 prepared by colloidal chemical method and calcined at 700℃ for 4 h was better. The existing acidic centers and basic centers matching with each other were the key to present better catalytic activity. The influence of reaction conditions on n-butanal self-condensation reaction was studied using the La-Al2O3 catalyst. The suitable reaction conditions were obtained as follows: mass ratio of catalyst to n-butanal 0.15:1, reaction temperature of 180℃ and reaction time of 8 h. Under the above conditions, the conversion of n-butanal was 90.6% and the selectivity of 2-ethyl-2-hexenal was 91.7%. La-Al2O3 could be reused for 4 recycles without losing its activity significantly. In addition, the by-products existing in the reaction system were identified by GC-MS analysis and then a possible reaction network for n-butanal self-condensation to 2-ethyl-2-hexenal catalyzed by La-Al2O3 was established.

Key words: n-butanal, La-Al2O3 catalyst, catalysis, aldol self-condensation, multiphase reaction, synthesis, 2-ethyl-2-hexenal

摘要:

辛醇(2-乙基己醇)是一种重要的增塑剂醇。正丁醛自缩合合成辛烯醛是工业生产辛醇的重要步骤之一。为克服工业正丁醛自缩合反应因使用强碱水溶液催化剂所带来的设备腐蚀、污染环境、生产成本高等缺点,采用La改性γ-Al2O3催化剂(La-Al2O3)催化正丁醛自缩合反应。首先研究了制备方法和制备条件对La-Al2O3催化性能的影响,发现采用胶溶法、于700℃下焙烧4 h得到的La-Al2O3催化性能较好,具有相互匹配的酸碱中心是催化性能较好的关键。以适宜条件下制备的La-Al2O3为催化剂,研究了反应条件对正丁醛自缩合反应的影响,得到适宜的反应条件为:催化剂与正丁醛质量比为0.15、反应温度180℃、反应时间8 h。在此条件下,正丁醛的转化率最高达到90.6%,辛烯醛的选择性为91.7%。该催化剂重复使用4次,催化活性无明显下降。通过对反应液进行GC-MS分析,确定了正丁醛自缩合反应体系中的副产物,进而推测了可能的副反应,建立了La-Al2O3催化正丁醛自缩合合成辛烯醛的反应网络。

关键词: 正丁醛, La-Al2O3催化剂, 催化, 羟醛缩合, 多相反应, 合成, 辛烯醛

CLC Number: