Study On The Preparation Of 3-methyl-N-octadecene Maleimide And Its Optical Properties And Applications

Due to the high biological activity and novel structure maleimide derivatives have become an important intermediate in organic synthesis.They are the most important“tools” in the “toolbox” of organic chemists,materials scientists and biochemists.Significant progress has been made in the development of maleimide derivatives applications during the past few years,such as radiotracers,organic light-emitting diodes(OLEDs),flat-panel displays,night-vision bioimaging.Nowadays,most of the synthetic methods related to maleimide derivatives have been synthesized by anhydrous and anaerobic methods.The process is complicated and the yield is low.According to the literature reports,the positions of the substituents introduced on the maleimide ring mostly occur at the C=C.The light-emitting intensity of the synthesized materials are very weak or do not emit in the solid state.In this paper,aiming at the problems of maleimide derivatives at the present stage,the preparation of maleimide derivatives and their composite materials are carried out for the development and application in the new fields.The main contents are as follows:1.Using oleylamine and citric acid to prepare an organic small molecule fluorescent material that emits yellow-orange light by one-step hydrothermal method.After nuclear magnetic resonance hydrogen spectrum and nuclear magnetic resonance carbon spectrum detection,the material has a maleimide ring.Then,detected by elemental analysis,mass spectrometry and infrared spectrum,the structure of organic small molecule fluorescent material was finally determined to be 3-methyl-1-(Octadec-9-en-1-yl)-1H-pyrrole-2,5-dione(MPO).The reaction mechanism is estimated based on the raw materials,products and synthetic methods.Next,the best experimental conditions,reaction temperature,reaction time,reaction raw material ratio,reaction solvent,and reaction raw materials,for preparing MPO were investigated.The effects of materials yield and fluorescence performance are screened.The optimal experimental conditions are determined as follows: 1.5 mL oleylamine and 1.8 g citric acid in the water under 200 ° C for 4 h,the yield can reach 81%.Next,the optical performance of MPO is tested.The test result shows that MPO has two excitation peaks locating at 386 nm and 522 nm respectively,and the emission peak position is 572 nm.The fluorescence intensity is 6000 a.u.The UV absorption spectrum of the material shows that absorption starts at 550 nm and peaks at 320 nm.The luminescent properties of MPO in different solvents are explored.The result shows that MPO has solvent effect.As the polarity of the solvent increases,the emission peak position of the material gradually shifts red.To further explore the fluorescence properties of MPO,the fluorescence lifetime is tested and the result is 75?s.The DSC and TAG tests are performed,the thermal weight loss does not exceed5% under 257 ° C,indicating that MPO has good thermal stability.Finally,the ground state configuration of MPO was optimized by density functional theory(DFT)calculation,and its molecular geometry and frontier molecular orbital(FMO)distribution were evaluated to further provide evidence for its excellent fluorescence stability.2.The previous chapter explored the photochemical and thermal stability of MPO.Based on that,MPO is combined with dibenzoyl peroxide,orthosilicate,silica aerogel,ethylene vinyl acetate copolymers.Four kinds of composite materials were prepared:light-emitting organic small molecule-organic glass polymethyl methacrylate,light-emitting organic small molecule-silica composite material,light-emitting organic small molecule-silica aerogel composite material,light-emitting organic small molecule resin composites.Optical tests on these four composite materials have good luminous properties even in the solid state.Except for the luminescent organic small molecule-resin composites,the emission peak positions of the four composite materials are basically same as pure MPO,and the peak positions are 565 nm,558 nm,564 nm,and 522 nm respectively.Next,the photothermal stability of the four composite materials are tested separately.The fluorescence spectrum is no change when the composite materials are exposed under sunlight for 10 days and in oven at120 ° C for 6 hours.It proves that the four composites light-emitting materials have excellent photothermal stability.The application of MPO composite materials provides a basis for the development of organic small-molecule light-emitting materials.