Research On The Technique Of High-throughput Microfluidic System For Synthesis Of Typical Salt-like Primary Explosives

Microfluidic reactors have emerged as an attractive technology in chemical synthesis,crystal control and other fields due to its precisely controlled reaction parameters,low reagent consumption and safe working.The differences of three typical salt-like primary explosives including Barium Trinitroresorcinate(Ba TNR),Silver Azide(SA)and Lead Azide(LA)in structural characteristics and preparation methods were fully analysized through microscale crystal growth kinetics in this paper.Meanwhile,two kinds of high-throughput microfluidic systems for the synthesis of typical salt-like primary explosives were designed and prepared.Furthermore,the synthesis of three typical salt-like primary explosives including Ba TNR,SA and LA have been investigated respectively.The main contents and conclusions are as follows:(1).The differences of typical salt-like primary explosives in solubility lead to the differences in their preparation methods,which in turn results in the differences in the design of high-throughput microfluidic system.Therefore,two sets of high-throughput microfluidic systems had been designed and prepared,namely the chaotic-segmented-flow coupled microfluidic system(CSFCMS)and the chaotic-flow microfluidic system(CFMS).(2).Both the nucleation rate and the growth rate of typical salt-like primary explosives are mainly determined by the diffusion process.The difference is that both the nucleation rate and the growth rate of Ba TNR are affected by the strength of diffusion,while the nucleation rate of SA and LA is hardly affected by the strength of diffusion.(3).In order to improve the volumetric throughputs of single microfluidic system,the study on parallelized microfluidic system technology was conducted.The results show that the parallelized fluid transportation network has a significant isofluid shunting effect on the premise of ensuring accurate fluid volume,and effectively suppresses fluctuations or changes in pressure drop on each branch and the resulting uneven fluid distribution,which lays a good foundation for the parallelization of high-throughput microfluidic systems.(4).Experimental study on the synthesis of Ba TNR at microscale was conducted using the CSFCMS.The results indicate that the optimal flow ratio of continuous phase to dispersed phase is 0.6/0.1.Additionally,the addition of Cetrimonium Chloride(CTAC)does not change the crystal shape of Ba TNR,but only its particle size distribution(PSD).However,the addition of Carboxymethylcellulose Sodium(CMC-Na)leads to the improvement of the crystal morphology of Ba TNR.The morphology of Ba TNR is changed to short columnar or spherical(spherical-like).(5).Experimental study on the synthesis of LA at microscale was conducted using the CFMS.The results show that the CFMS can be used for the rapid preparation of five kinds of LA,including crystalline-LA,poeder-LA,dextrin-LA,polyvinyl alcohol(PVA)-LA and CMCLA.Additionally,the optimal experimental conditions for the synthesis of five types of LA were obtained using the CFMS.(6).Experimental study on the synthesis of SA at microscale was carried out using the CFMS.The results show that the optimal flow rates of the two reactants are both 4.0 m L/min.Compared with preparation in a beaker,SA synthesized by the CFMS has good crystal morphology,larger particle size and narrower PSD.In addition,to evaluate the safety performance of the SA synthesized by the microreaction system,the impact sensitivity(IS)and electrostatic sensitivity were investigated.The results indicate that SA synthesized by the CFMS is insensitive to impact and electricity.