Analysis Methods Study For The Product And By-products From The Reaction Liquid Of Solid Phosgene Synthesis Of 1,5-naphthalene Diisocyanate

1,5-Napthalene diisocyanate(NDI) is a special isocyanate, which has an important use in many special fields. NDI possesses strong chemical activity due to the structure contains two –NCO groups and caused difficulties to analysis. There is an obstacle to track the reaction process and optimize the synthesis process since lack of proper quantitative analysis methods for NDI. In order to solve this problem, both quantitative analysis of main product method and qualitative analysis of related byproducts method in the reaction system of solid phosgene synthesis NDI were researched in this dissertation. The main contents and conclusions of the present dissertation are as follows three aspects:1) A normal-phase high-performance chromatography method for direct determination the NDI product has been established. Both NDI coarse sample and reaction system of solid phosgene synthesis NDI sample without any derivative pretreatment can be directly analyzed by using this method. The overall analysis time could save significantly and analysis process could simplify with this method. The method has a good linear correlation with the correlation coefficients above 0.999, the average recoveries were 98.5%~101.7%(n=3) and the relative standard deviations(RSD) were 0.670%~0.705%. This method not only has a high accuracy and repeatability but also is quick and easy. Meanwhile it can be used to quantitative analysis of NDI products and NDI from the reaction liquid.2) A reversed phase high performance liquid chromatography method has been established by optimizing the derivative agent, derivative way, derivative time and chromatographic conditions. This method uses methanol as derivative agent, methanol-water as mobile phase and can greatly reduce the cost of analysis. It has a good linear correlation with the correlation coefficients above 0.999, the average recoveries were 97.99%~99.55%(n=3), the relative standard deviations(RSD) were 0.71%~1.40% and the detection limit was 0.0128 mg/L(S/N=3). The method has high accuracy, good reproducibility, low detection limit and can be applied to detect the NDI products.3) The ultra high performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS) and Fourier transform infrared spectroscopy(FTIR) qualitative analysis methods were established. Those two methods can be applied to detect the possible byproducts in the reaction system of solid phosgene synthesis NDI. In order to ensure the qualitative analysis results accurately and reliably, we verified the results of UPLC-MS/MS by changing the analysis conditions and contrasted the results of FTIR by using standard. We can infer the possible byproducts in reaction system of solid phosgene synthesis NDI by combining with the results of the two qualitative analysis methods. It can provide guidance for speculating reaction mechanism and optimizing reaction conditions in the reaction system of solid phosgene synthesis NDI.