One-Pot Sequential Aldol Condensation and Hydrogenation of n-Butyraldehyde to 2-Ethylhexanol

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• 作者：Ying Li ; Xiaohong Liu ; Hualiang An ; Xinqiang Zhao ; Yanji Wang
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2016
• 出版时间：June 8, 2016
• 年：2016
• 卷：55
• 期：22
• 页码：6293-6299
• 全文大小：288K
• 年卷期：0
• ISSN：1520-5045

文摘

2-Ethylhexanol (2EHO) is an important organic chemical. The industrial production of 2EHO comprises three units: propylene hydroformylation to n-butyraldehyde, n-butyraldehyde self-condensation to 2-ethyl-2-hexenal (2E2H), and 2E2H hydrogenation to 2EHO. In the present work, 2EHO was synthesized by one-pot sequential aldol condensation and hydrogenation of n-butyraldehyde. Among a series of metal–solid acid bifunctional catalysts, Ni/La–Al₂O₃ showed a better catalytic performance. The effect of reaction conditions on the one-pot sequential synthesis of 2EHO catalyzed by Ni/La–Al₂O₃ was investigated, and the suitable reaction conditions were obtained as follows: weight percentage of Ni/La–Al₂O₃ = 15%, self-condensation reaction conducted at 180 °C for 8 h, and then hydrogenation reaction conducted at 180 °C for 6 h under 4 MPa H₂ pressure. Under the above reaction conditions, n-butyraldehyde conversion attained 100% at a 2EHO selectivity of 67.0%. The inhibition of Ni to n-butyraldehyde self-condensation reaction is responsible for the low selectivity of 2EHO. On the basis of the analysis of the reaction system, some side reactions in the one-pot sequential synthesis of 2EHO were proposed. The deactivation of Ni/La–Al₂O₃ was due to the agglomeration of Ni and La₂O₃ particles and the occurrence of γ-Al₂O₃ hydration. Introduction of some hydrophobic groups on the surface of γ-Al₂O₃ could effectively inhibit the hydration of γ-Al₂O₃.