无碱条件下氧气催化氧化2-乙基己醇合成2-乙基己酸

Base-free Catalytic Oxidation of 2-Ethylhexanol to 2-Ethylhexnoic Acid with Oxygen

摘要:

以2-乙基己醇作为原料、O2作为氧化剂，无碱参与下催化氧化合成2-乙基己酸。使用气相色谱(GC)进行定量分析，气质联用仪(GC-MS)进行定性分析。考察了催化剂、溶剂、反应温度、时间及氧压力对反应的影响。结果表明：TEMPO/硝酸铜为合适的催化剂体系，乙酸乙酯为合适的溶剂。适宜的反应条件是：催化剂TEMPO用量为2-乙基己醇摩尔量的5%、硝酸铜用量为2-乙基己醇摩尔量的4%，100℃、0.5MPa O2压力下反应6h，2-乙基己酸收率可达77.1%。O2恒压条件下该反应是拟一级反应，反应活化能为59.9kJ/mol。主要副产物是3-庚醇和3-庚酮。

Abstract:

2-ethylhexnoic acid was prepared by catalytic oxidation of 2-ethylhexanol using O2 as an oxidant under base-free condition. Quantitative analysis was performed by gas chromatography (GC), and the qualitative analysis was carried out by GC-MS. The effects of catalyst, solvent, reaction temperature, time and oxygen pressure on the reaction were investigated. The results showed that TEMPO/Cu(NO3)2?3H2O was the efficient catalyst system, and ethyl acetate was the suitable solvent. Under the optimum conditions , the yield of 2-ethylhexnoic acid could reach 77.1%, when TEMPO was 5% mole of 2-ethylhexanol, Cu(NO3)2?3H2O was 4% mole of 2-ethylhexanol, and reaction at 0.5MPa O2, 100℃ for 6h. Under the constant oxygen pressure, the reaction is a pseudo first order reaction and the activation energy is 59.9kJ/mol. The main by-products are 3-heptanol and 3-heptanone.