Study On The Technology Of Synthesizing Ketone Musk By Nitration In Microchannel Reactor

Microchannel reactor is a miniature chemical reaction unit,which has the characteristics of high-efficiency mixing,high heat and mass transfer efficiency,strict control of reaction time,easy to scale up,high efficiency of continuous operation and high safety factor,etc.Micro-channel reactor is used in organic synthesis reactions It is suitable for those reaction processes with strong exotherm and high temperature and high pressure,which are widely involved in the fields of fine chemicals and pharmaceuticals.The synthesis of high-end artificial fragrance ketone musk involves the nitration reaction.The production process of the traditional kettle reactor is complicated and the safety is low.Therefore,in the early stage of this article,we use the micro-channel reactor small equipment to carry out the nitration reaction of ketone musk synthesis and conduct process optimization research.The development amplification and optimization provide theoretical and technical support.In the early stage of this article,Caterpillar microchannel test equipment was used to conduct nitrification experiments to explore the relevant influencing factors of the nitrification reaction,and the investigation included suitable material ratios（proportion of p-tert-butylacetophenone and dichloroethane,mixed acid）,Reaction temperature,delay pipeline length,residence time and other factors.The results show that the suitable process conditions for the synthesis of nitroketone musk in the microchannel reactor are the Mass ratio of p-tert-butylacetophenone and dichloroethane is 1:5,and the Mass ratio of substances of mixed acid is concentrated nitric acid:concentrated sulfuric acid=1:1.892,T=10℃,the length of the delay pipeline is 3 m,the residence time is controlled at 3 min,the mass fraction of ketone musk in the product reaches 77.67%,which is 68.00%compared with the mass fraction of ketone musk in the workshop reactor reactor has seen an increase.In the simulation part,ANSYS general software CFX was used to simulate the microchannel reactor in musk synthesis,the grid independence was verified,the effect of changing the raw material ratio on the mass fraction of ketone musk was investigated,and the microchannel hydraulic power was also studied.The influence of the diameter and the angle between the inlet and the inlet on the mixing performance was obtained by simulation,and the flow rate,temperature,and mass distribution distribution map of the target product were obtained,and then the internal mixing condition of the microchannel was understood.When the ratio is 10:4,the product ketone musk has the highest mass fraction;keeping the acylate volume flow rate unchanged at10 ml·min^-1,while maintaining the optimal raw material ratio（acylate:mixed acid=10:4）,by changing the microchannel The hydraulic diameter of the product shows that when the hydraulic diameter is 150microns,the product ketone musk has the highest mass fraction;keeping the acylate volume flow rate unchanged at 10 ml·min^-1,while maintaining the optimal raw material ratio（acylate:mixed acid=10:4）,and The hydraulic diameter is 150 microns,and the feed angle of the micro-mixer is changed.It can be found that when the feed angle of the micro-mixer is 180°,the mass fraction of ketone musk is the highest.The comparison between the experimental data and the simulation results further provides ideas for the optimization of the microchannel reactor structure,and also provides technical suggestions for the scale-up study of the microchannel reactor and the design of the new mixer.In the later stage,nitrification experiments were carried out with Chinese equipment of Star Lam series microchannel reactors to explore the relevant influencing factors of the nitrification reaction,and the investigation included suitable material ratios（proportion of p-tert-butyl acetophenone and dichloroethane,ratio of mixed acid）,Factors such as reaction temperature,length of delay pipeline,residence time and other factors.The results show that the suitable process conditions for the synthesis of nitroketone musk in the microchannel reactor are the Mass ratio of p-tert-butylacetophenone and dichloroethane is 1:6,and the Mass ratio of substances of mixed acid is concentrated nitric acid:concentrated sulfuric acid=1:1.911,T=8℃,the length of the delay pipeline is 4m,the residence time is controlled at 3.1min,Dichloroethane as solvent,the mass fraction of ketone musk in the product reaches 78.02%,which is68.00%compared with the mass fraction of ketone musk in the workshop reactor reactor has seen an increase.The structure of the micro-channel reactor is simple.It can be amplified by the array to increase the number of micro-channel mixers to increase the output.There is no amplification effect.The small test and the Chinese type have achieved good results.It can be obtained through the small and Chinese experiments.The reaction and industrial reaction parameters are consistent,that is,repeating the parallel operation of the same microreactor can complete the output of the target product,without the need to scale up the test steps,saving development time and expensive equipment costs,which is also the biggest advantage of the microreaction system.