Abstract:

In the H₂O₂/acetonitrile system, MgO prepared by precipitation method was used as a catalyst to catalyze the Baeyer-Villiger (B-V) oxidation of cyclohexanone to synthesize ε-caprolactone. The effect of the preparation conditions and reaction conditions on the conversion to cyclohexanone and the yield to ε-caprolactone were discussed. According to the experimental results, Mg(NO₃)₂·6H₂O was used as the precursor, and the best oxidation performance was obtained when the calcination temperature was 600℃ and the calcination time was 2 h. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used. The analysis results show that the MgO particle increases from 9.53 nm to 29.49 nm when the temperature is in the range of 500℃ to 800℃. In n(catalyst)∶n(cyclohexanone) = 0.45∶1, n(acetonitrile)∶n(cyclohexanone) = 12∶1, n(hydrogen peroxide)∶ n(cyclohexanone) = 10∶1, 70℃, 6 h, the conversion rate of cyclohexanone was 95.2% and the yield of ε-caprolactone was 83.1%. The mechanism of hydrogen peroxide B-V oxidation of cyclohexanone was studied in-depth, and the reaction was analyzed in real time by online in-situ infrared spectroscopy. The peroxyacetal reaction path was verified.

Key words: cyclohexanone, ε-caprolactone, organic compound, oxidation, reaction mechanism

摘要：

在H₂O₂/乙腈体系下以沉淀法制备的MgO为催化剂催化Baeyer-Villiger（B-V）氧化环己酮合成ε-己内酯，考察了制备条件和反应条件对环己酮转化率和己内酯收率的影响。根据实验结果，Mg(NO₃)₂·6H₂O为前体，在煅烧温度为600℃、煅烧时间为2 h时制备MgO氧化性能最佳，由X射线衍射（XRD）、扫描电镜（SEM）进行了分析，可知随温度升高MgO粒径逐渐增大，500~800℃范围内，MgO晶粒尺寸由9.53 nm增大到29.49 nm。在n（催化剂）∶n（环己酮）=0.45∶1、n（乙腈）∶n（环己酮）=12∶1、n（双氧水）∶n（环己酮）=10∶1、70℃、6 h时获得环己酮转化率95.2%及ε-己内酯收率83.1%。对双氧水B-V氧化环己酮机理进行了深入的研究，采用在线原位红外光谱对反应进行实时监测与分析，验证了其过氧缩酰胺反应路径。

关键词: 环己酮, ε-己内酯, 有机化合物, 氧化, 反应机理