Highly efficient synthesis of benzyl benzoate directly from self-coupling of benzyl alcohol in water

Benzyl benzoate(BB),an important ester,still demands for green synthesis routes.In this work,by size regula-tion and proper functionalization of carbon nanotubes(CNTs)as the support of gold catalyst,this ester can be synthesized very efficiently directly from benzyl alcohol via oxidative coupling.More attractively,the reaction is performed using water as green solvent and molecular oxygen as green oxidant.Simultaneously,very high selectivity to BB can be obtained near full conversion within very short reaction time(just 0.5 h),while the low-value benzoic acid byproduct is negligible.This is very different from many reported gold catalysts that yield much benzoic acid and/or benzaldehyde in water.The results show that,besides the size of CNTs(length and diameter),the functionalization of CNTs is also critical for improving both conversion and the selectivity to BB.In addition,the reaction mechanism for forming BB ester is put forward as well.

循环流化床相似准则及数值验证

基于适用于同一装置的Shi相似准则和适用于不同装置的Horio相似准则,本研究提出了不受颗粒直径与反应器直径比限制的循环流化床流动相似准则。通过数值模拟方式验证了已有Shi准则在同一装置中的适用性,同时也是对所采用数值模型的验证,随后在不同比例装置中对本研究所提出的相似准则进行了模拟。对不同比例装置中气速变化、颗粒直径变化以及气速和颗粒直径同时变化的工况进行模拟,结果表明所提出的相似准则在固相浓度轴向分布、固相浓度径向分布和无因次速度径向分布上具有相似性,进一步通过压力波动特征探讨了宏观相似下的介观分布特征。

基于OpenFOAM模拟精馏塔板的气液流动

本研究对筛孔型精馏塔板上的空气-水两相流进行了模拟,模拟方法采用基于开源软件平台OpenFOAM的双流体模型框架。模拟体系选用Solari-Bell经典实验体系,研究了不同操作条件下的气液两相流动参数,包括清液层高度、气相速度、液相速度和塔板压降等,模拟结果与实验结果的变化趋势基本一致。基于CFD模拟结果,分析了不同工况下塔内气液两相速度场与气含率分布等流动参数,结果表明本工作可以较好地捕捉塔板上的气液流动特征。进一步地,讨论了应用OpenFOAM模拟精馏塔内气液两相流动的若干影响因素,在此基础上分析了气液错流体系相间曳力对模拟结果的影响,实现了与使用商业软件模拟结果相接近的预测效果,验证了使用OpenFOAM模拟精馏塔体系的可行性。