Synthesis And Application Of Novel Ultraviolet Light Absorbers

Long time UV irradiation will not only affect human skin health,but also accelerate the degradation of polymer materials.Therefore,anti UV protection has become one of the important research topics at home and abroad.UV absorbers protect substances by absorbing UV light and releasing absorbed energy in the form of heat or light.The traditional UV absorbers have the disadvantages of small molecular weight,easy migration,poor light stability,easy absorption by human body and yellowing of materials.In this paper,two kinds of new structure compounds have been synthesized by molecular design,in order to develop high-efficiency,low toxicity and good comprehensive performance of UV absorbers.In the first part,benzophenone compounds were synthesized from dihydroxybenzophenone analogues and acyl chloride or Haloalkynes.The structure of the product was characterized by ¹H NMR,¹³C NMR and HR-MS,and the optimum reaction conditions were discussed.The products 3 and 4 were analyzed by UV-Vis.The photostability of product 3 and its application as UV absorber in UV curable coatings were further studied.The results show that the products are more stable than the commercial UV-0 absorbers.At the same time,the three-dimensional structure of product 3e was characterized by X-ray single crystal diffraction,and the density functional theory calculation was carried out on the model structure.It is preliminarily speculated that product 3e can quickly absorb ultraviolet rays and carry out charge transfer.On the other hand,on the basis of the above research and analysis,it is found that the product 4 can be used as UV initiator in the UV curing coatings,and the curing time,the hardness,adhesion and gel rate of the cured film are better.In the second part,new linear 1,3-butanediynes were synthesized,and their UV absorption and photostability were studied.1,4-diaryl-1,3-butanediynes were synthesized from benzothiophene by three steps.The structure of the product was characterized by ¹H NMR,¹³C NMR and HRMS,and the optimum reaction conditions for the last step were discussed.At the same time,the target product 5 was analyzed by UV-Vis absorption spectrum and optical stability.The product 5a-5c can effectively absorb 260-370 nm ultraviolet light,and has strong absorbance.Compound 5a was further added to the light-curing coating as an ultraviolet absorber,and it was found that compound 5a can absorb ultraviolet light for a long time and has good light stability,which is better than the commercially available ultraviolet absorber UV-0;Compound 5a can also effectively improve the cured film The hardness and adhesion,while having good thermal stability.