Synthesis And Properties Of Azobenzene Compouds Containing Schiff Base Or Biphenyl Group

In recent years,organic photochromic materials have played an important role in many high-tech fields,such as optical information storage,nonlinear optical materials and military camouflage and so on,due to their high discoloration efficiency,fast response speed,bright color and other characteristics.The azo-compound containing Schiff base group is a kind of chromic compound which possesses photochromic properties or thermochromic performance.The azobenzene molecular structure contaning Schiff-base group not only could occur cis-trans isomerization by UV-light-induced,but also has the thermochromic performence.The azobenzene Schiff base compound will have broader application prospects,which involves in medicine,catalysis and analytical chemistry.In addition,the compound containing π-π conjugated system has thermal and photoelectricity properties.As representatives of such substances,biphenyls have a wide range of applications.When photosensitive group,-N=N-,is introduced into the biphenyl structure,the compound can occur cis-trans isomerization under the irradiation of the light which makes it possess photochromic property.While the compound is heated it can exhibit different colors because of the change of crystal structure of biphenyl unit.This kind of compound has good potential application performance.Except for the usage in optical information storage,photochromic compound can also be used in light shielding due to its sensitivity to ultraviolet light.Azo Schiff base is an important class of light sensitive compound which can absorb ultraviolet to convert it to less harmful energy through change of cis-trans isomerization or intermolecular proton transfer.Therefore,it is an ultraviolet absorber and can be used as light fastness improver.Six kinds of azo Schiff base compounds were synthesized by the reaction of aniline derivative and salicylaldehyde.The photochromic and thermalchromic properties were discussed.The structure of the compounds was characterized through FT-IR and elemental analysis.The UV-visible spectra was used to study photochromic properties of the compound and polarizing microscope with a hot stage was used to investigate thermalchromic properties if the compound.In the second part of the experiment,the azobenzene compound conntaning biphenol skeleton was achieved through acylation and esterification reaction,then the azo group was introduced into the skeleton by diazotization and coupling reaction.The target compound,GR1,with chromic properties was synthesized.The structure was determined and characterized through TLC,FT-IR and elemental analysis.The chromic properties were studied as before.In the third part,the cotton fabrics were finished using the two synthesized azo Schiff base compounds containing reactive groups.The anti-UV property of the finished fabric was explored by measuring UV transmittance and ultraviolet protection factor.The possibility of improving light fastness of reactive dyes was determined by detecting light fastness.