Synthesis Of Polymerizable Benzotriazole Ultraviolet Stabilizers

For more and more serious air pollution and being badly destroyed ozone layer, muchmore ultraviolet ray arrives the ground. The influence on the human obviously increases.Then ultraviolet ray absorbent becomes very important now. Benzotriazole ultravioletabsorbent are now the most prominent and effective stabilizers for plastics materials,especially automotive coatings. But because its molecular weight is quite small, it can easilymove to the surface and volatilize, and can not be effective over a long period of time. Thenhow to inhibit moving, volatilizing, being leached out by solvents and being removed in anyother way of the ultraviolet absorbents from the material was studied. Furthermore, theadditive must be evenly distributed, which requires that it is compatible with the polymer.Then we can introduce polymerizable group into the ultraviolet absorbent moleculars, thus itcan homopolymerize to produce high molecular weight ultraviolet absorbent, or it canpolymerize with macromolecular material to get a product which can bear the ultraviolet rayforever. Two polymerizable benzothriazole ultraviolet absorbents are designed andsynthesized in present paper.Different Alkylogens react with p-methyl phenol to get corresponding ethers, and thenthrough rearrangement, phenol containing double bond is obtained. The synthesis processesof intermediate pigment of benzothriazole ultraviolet absorbents from this phenol throughcoupling and reducing is studied.The structures of the intermediates are confirmed by MSand NMR. The contents are analyzed by HPLC. Different reaction conditions are investigated.Optimal reaction conditions are found.With rongalite used as reducing agent, two benzothriazole ultraviolet absorbers aresynthesized by reduction. Effects of the quality of the starting materials, molar ratio of rawmaterials, feeding temperature, stirring rate, reaction temperature, reaction time areinvestigated. Contents of the product match the demand by the pilot production. Thestructures of the ultraviolet absorbents are confirmed by MS and NMR. The contents areanalyzed by HPLC. The UV absorption spectrums of the two products in chloroform, methanol and tolueneare determined, and by being contrasted with UV-P, it is confirmed that the ultravioletabsorption region do not be effected by different substitute groups. The products are fineultraviolet ray absorbents.