Study On Continuous O-Ethylation Of Butanone Oxime In A Microcapillary Reactor

Oxime ether and its derivatives are highly value-added chemical intermediates and important raw materials for alkoxy amino hydrochlorides, which are intermediates for the preparation of pharmaceuticals and pesticides. The industrial demands of oxime ether and its derivatives grow fast. Although the traditional batch O-alkylation of butanone oxime process reaches high yield, and the unreacted raw materials are easy to recycle, the operation method is complex, the reaction time is too long, the system can easily tend to be overheated, the product quality can be unstable, and it may cause potential serious safety hazards. In recent years, flow chemistry under continuous flow conditions using microreaction technology promotes a wide range of applications due to the large surface area, excellent heat and mass transfer performance of microreactors. It ensures uniform distribution of the reactants, and the temperature of the reaction system is maintained. It can improve transfer performance, intensify the reaction process and enhance the safety of multiphase systems. These outstanding advantages exhibit good prospects for industrial applications. Continuous O-alkylation of butanone oxime in a microcapillary reacor may help to solve the above problems in the traditional process for the synthesis of butanone oxime ether, and this procedure can be converted to continuously produce on industrial scale.This thesis is divided into six chapters. It mainly includes the synthesis of butanone oxime ether by continuous O-alkylation of butanone oxime with the basis of batch experimental data, the investigation of the effects of microchannel dimension, alkali concentration, temperature, contact time and molar ratio of raw materials, which provides a practical way for industrial scale-up.Chapter1is the literature review which summarized the research progress of O-alkylation in recent years and given an introduction to the concept and related applications of flow chemistry.Chapter2introduces the experimental materials, experimental equipments, as well as experimental and analysis methods. It is mainly about:butanone oxime was fed continuously with a precision micro advection pump, and butanone oxime O-alkylation reaction was carried out in a stainless steel microcapillary reactor. Toluene was used as the extractant. The product was analyzed by gas chromatography and n-butanol was used as the internal standard for the processing of experimental data with internal standard method.Chapter3examines the batch preparation of butanone oxime ether and selects the optimum alkylating agent. The batch experimental data were used as the reference for design of continuous O-alkylation of butanone oxime in a microcapillary reactor. It is found that O-alkylation of butanone oxime reactivity and butanone oxime ethyl ether selectivity are highly affected by alkylating agent, diethyl sulfate could give a butanone oxime conversion rate of99.28%and butanone oxime ethyl ether selectivity of70.73%.Chapter4carries out the experimental research on continuous O-alkylation of butanone oxime in microcapillary reacors. The effects of microchannel dimension, alkali concentration, temperature, residual time, and molar ratio of raw materials were investigated. The good butanone oxime O-ethylation effect was generated while the molar ratio of NaOH and butanone oxime was1:1, and the molar ratio of DES and butanone oxime was1:1in Φ1mm microcapillary reactor with23wt%NaOH(aq) under ambient pressure for60min at40℃, could give a butanone oxime conversion rate of89.54%and butanone oxime ethyl ether selectivity of68.22%.Chapter5provides the ideas for industrial reactor scale-up of the butanone oxime O-ethylation process using flow chemistry technology, and the method is compared with the traditional batch industrial production processes. The total szie of microchannel reactors needed is much smaller than agitated vessel when flow chemistry technology is adopted for O-ethylation of butanone oxime, and amplification effects are avoided as well.Chapter6summarizes the main contents of this article, and gives some suggestions on the further research of continuous process for butanone oxime O-ethylation reaction.