Synthesis And Performance Study Of Diaryl Naphthopyran Photochromic Compounds

Photochromic materials will change their color because of chemical structurechange when opposed to the sunlight. This kind of change makes them applicable inthe field of optical information storage, photo-induced adjusting, photoswitch,anti-counterfeiting, decoration, photochromic supermolecule and so on.Among manyof photochromic compounds, the color mainly changes from colorless or some othercolor to purple, blue or yellow, seldom can change color from colorless to red.Naphthopyran photochromic compound is a kind of very importantphotochromic material which could change color from colorless to red byintroducing some groups onto the naphthopyran ring. Though very fewphotochromic materials can achieve bulk production,2,2-diphenyl-3H-naphtho-[2,1-b] pyran accomplished, and it belongs tonaphthopyran photochromic materials. As the synthesis of other photochromiccompound, the yield coefficient of the synthesis of naphthopyran compound is verylow, and the cost of the raw material is very high, both of the reasons lead to thedifficulty of the production industrialization. To improve the yield coefficient, weresearched the reaction conditions systematically, then amplificatory experiment istook for preliminary industrialization.We synthesized seven naphthopyran compounds under the best reactionconditions, their structures have been identified through¹H NMR,¹³H NMR, IR andMS, and their photochromic property has also been studied. We studied theregularity of the solvent effect, concentration effect, electronic and steric effect ofsubstituent group effect on the photochromic property of the naphthopyrancompounds. At last, we also discussed the photochromic property when dispersedthe photochromic compound into the polymer media.Our research found: the synthesis temperature of the Grignard reagent, thetemperature of Grignard reaction, the ratio of the reagent and the time that the finalcompounds refluxed in the methylbenzene, all of which have great influence on theyield coefficient; when it dissolved in the solution, both the choice of the solvent andthe concentration influence greatly on the photochromic property of the naphtopyranphtotochromic compounds; the absence of the polymer media improved theendurance of the photochromic materials observably.