Synthesis And Properties Of Novel Polymerization Inhibitor For Styrene Rectification

As a kind of important chemical reagent,styrene will cause irreversible loss of styrene monomer because of self-polymerization in the process of production,storage and transportation.Therefore,the addition of polymerization inhibitor in styrene monomer can prevent or slow down the polymerization rate,so that the storage time of styrene is longer,which is of great significance to the industrial production of styrene.At present,styrene inhibitors are mainly nitro inhibitors,which have high nitrogen content and great pollution to the environment,which is contrary to green chemistry and chemical industry.As a new type of polymerization inhibitor,QM-ph has good polymerization inhibition performance and is expected to replace nitro inhibitor in industry.However,the development time of QM-ph is relatively short,and many problems still need to be solved to realize its industrial production.Firstly,the synthesis process of QM-ph was improved,and the target product was synthesized by Mannich method.The expensive piperidine was replaced by di-n-propylamine,which greatly reduced the reagent cost.On this basis,the effect of different raw material ratio(2,6-di-tert-butylphenol: benzaldehyde: di-n-propylamine)on the yield was explored.The highest yield was obtained when the ratio of 2,6-dit-butyl phenol: benzaldehyde:din-propylamine was 1:1.15:1.3.In order to further reduce the experimental cost,the di-n-propylamine were recycled,and it was found that the recycled di-n-propylamine had no significant effect on the yield,and the yield was between 70%-75%.In order to achieve the industrial standard of QM-ph production,the treatment of reducing the nitrogen content of the productwas also done(the by-product Mannich base contains nitrogen),and the nitrogen content of the products was reduced from 0.8% to 0.479%.In addition,the reaction heat in the process of QM-ph reaction was explored to further pave the way for its industrial production.The industrialization and the exploration of novel polymerization inhibitors is an important topic.Inspired by the above inhibitors,the synthesis and inhibition properties of imine inhibitors,quinone inhibitors and oxime inhibitors were also studied.Through the study,it is found that the polymerization inhibition stability of imines is poor,the solubility of quinone inhibitor in ethylbenzene is poor.The ideal inhibitor is not obtained.In the exploration of oxime inhibitors,a new compound: O-n-butyl oxime was synthesized.The test of polymerization inhibition performance showed that it had certain polymerization inhibition.