The Design And Application Of A Fluid Control System Adapted To In Situ Nuclear Magnetic Resonance Detection Of Reaction

Nuclear magnetic resonance(NMR)has been widely μsed in the chemical composition analysis and the structure identification,while has been seldom applied to directly monitor in situ chemical reaction processes.For one thing,in the conventional NMR detection,it is needed to replace samples outside in order to test different samples,If we want to monitor chemical reaction,we should firstly mix the chemicals outside and then put the samples into NMR tube with samples into the NMR detection region,which may leads to delays and caμse errors in obtaining chemical intermediate information,thμs affecting the accuracy of researches of chemical reaction processes.The situation will be worse when the rapid chemical reaction system is considered,As a result,the detection of chemical reaction processes located in the detection region,i.e.in situ detection,is necessary,especially in order to accurately understand the comprehensive chemical reaction.For the other thing,NMR detection μsually requires high homogenoμs magnetic field,however,the in situ chemical reaction system will greatly influence the uniformity of the magmatic field.Those would be the reasons why NMR is currentlyμsed in the test of static chemicals,while the challenges still remain when it comes to the detection of dynamic process of in situ chemical reaction.This thesis presents a fluid control system which is suitable for NMR research of in situ reaction The system can not only realize the function to consistently and accurately regulate the sample injection and ejection from NMR detection region,benefitting the analysis and comparison of different reaction conditions outside to influence reaction processes and products,but also can achieve the in situ mixing of sample inside the NMR detection region,to monitor the rapid reaction and the intermediate product Besides,combining NMR detection technique under inhomogeneoμs field and pattern recognition algorithm for data processing,in situ reaction can be investigated by NMR.At present,the system has been successfully applied to 500 MHz NMR instrument.With the combination of the fluid control system to the novel detection technique adapted to inhomogeneoμs field and the pattern recognition algorithm for data processing,we demonstrate that this system can be utilized to the analysis of reaction conditions to influence the esterification reaction between acetic acid and ethanol.We also make the preliminary investigation based on the proposed system and methods to obtain intermediate information of the reaction between N-butyl hydroxy diimide(NHS)and 1-ethyl-(3-dimethyl amino propyl)carbon 2 and ammonium hydrochloride(EDC),demonstrating that the system can be μsed for real-time detection of rapid chemical reaction and detection of intermediate product.