高校化学工程学报2017，Vol.31Issue(1)：58-66,9.DOI:10.3969/j.issn.1003-9015.2017.01.009
超声波辐射P2O5催化环己酮肟液相贝克曼重排合成己内酰胺
Ultrasonic Radiation Synthesis of ε-Caprolactam via Liquid-Phase Beckmann
Rearrangement Cyclohexanone Oxime Catalyzed by P2O5
程庆彦 1朱响林 1王延吉 1赵新强1
作者信息
- 1. 河北工业大学绿色化工与高效节能河北省重点实验室,天津 300130
- 折叠
摘要
Abstract
The catalytic performance of P2O5 over Beckmann rearrangement of cyclohexanone oxime (CHO) to prepareε-caprolactam (CPL) under ultrasonic radiation was studied. The effects of ultrasound intensity, species and amount of solvent and ultrasonic radiation time were investigated. Under conditions of CHO 0.01 mol, P2O50.25 g, 10 mL dimethylformamide (DMF) and ultrasound intensity 0.29 W?cm-2at room temperature with ultrasonic radiation of 1.5 h, CHO conversion of 99.1% can be achieved with CPL selectivity of 99.4%. The mechanism of Beckmann rearrangement with P2O5under ultrasonic radiation was studied by on-line IR analytical system. The results indicate that hydrogen bond is formed between carbonyl of DMF and ortho methylene of C=N-OH under ultrasonic radiation. P and O from P2O5 form coordinate and hydrogen bonds with N from DMF and aldehyde group from DMF, respectively, which leads to DMF adsorption onto P2O5.CHO is adsorbed by P2O5via H (from N+OH2 of CHO) and O (from P2O5) interaction to form hydrogen bond, and O (from NOH of CHO) and P (from P2O5) interaction to form P-OH. Hydrogen proton transfers from N to O to form H2O, while the electron cloud density of methylene increases due to hydrogen bond formation between carbonyl of DMF and ortho methylene of C=N-OH, which contributes to nucleophilic attack of methylene on nitrenium ion to form carbocation. The carbocation interacts with the formed H2O by losing hydrogen proton, which leads to CPL formation via isomerization.关键词
超声波辐射/环己酮肟/液相贝克曼重排/己内酰胺/P2O5Key words
ultrasonic radiation/cyclohexanone oxime/liquid-phase Beckmann rearrangement/caprolactam/P2O5分类
化学化工引用本文复制引用
程庆彦,朱响林,王延吉,赵新强..超声波辐射P2O5催化环己酮肟液相贝克曼重排合成己内酰胺[J].高校化学工程学报,2017,31(1):58-66,9.
