.1,8 - Naphthalimide Fluorescent Dye Synthesis And Applications

In this research,the study of fluorescent dyes is in the automotive air-conditioning system in the application of fluorescence leak detection.It is,search or synthetic fluorescent dyes which can be applied to fluorescent leak detection in the vehicles air-conditioning system.There are mainly from two aspects of the experimental study.On the one hand,selected suitable fluorescent dyes which are taken from the market.On the other hand,synthetic suitable fluorescent dyes by research.The research bought various fluorescent dyes from home and abroad.And studied the solubility of them in lubricant(PAG) which was applicable to automotive air-conditioning system with the type of R-134a refrigerant.Selected suitable fluorescent dyes that the choice standard was the solubility.Finally Selected three fluorescent dyes with obviously yellow-green fluorescence under UV irradiation and solubility in lubricant.These were Solvent Yellow 8GF-1,Solvent yellow 571 and Solvent Yellow 43.Their solubility were 0.2mg/ml,0.3mg/ml,0.8mg/ml.However, the viscosity,fluorescence intensity of the fluorescent agents could not reach the fluorescent leak detection requirements when were diluted.The study tried to add some organic amines into the fluorescent agents which aim to increased the solubility of the suitable fluorescent dyes.But the result was unsatisfactory.The study detected the UV wavelength scan the whole map and fluorescence spectrometry of the three suitable fluorescent dyes.And these spectrums could be as the reference and experimental evidence for the next phase of the synthesis experiment.Use the application of the foregoing tests and many references as a guide,the study synthesized the intermediate product 4-bromo-N-octadecyl-1,8-naphthalimide used 4-bromo-1,8-naphthalene dianhydride as raw materials through the imidization reaction.To yield and margin of melting point as indicators optimized the imidization process through single-factor test and orthogonal test,that was 4-bromo-1,8-naphthalene dianhydride Without purified and Octadecylamine were one-time fed and their ingredient ratio was 1:1.08.The reaction temperature was heated to 60℃then cooled down to 50℃.The reaction time was 3h.The reaction deposit overnight then filtrated it.The yield of the intermediate product 4-bromine-N-18 alkyl-1,8-naphthalimide was up to 81.6%.Detected infrared spectra of the intermediate product,and it meet the requirement of the design.The study also measured fluorescence spectrometry of the intermediate product.The study synthesized yellow or orange goal products 4-alkoxy(phenoxy)-N -octadecyl-1,8-naphthalimide through the substitution reaction which used product last step and alcohols as raw materials in alkaline conditions and the existence of surfactant.The conditions of synthesis was 80℃water-bath heating.The reaction time was 6h.The study detected the solubility of the goal products in lubricants,their fluorescence spectrometry,UV wavelength scan the whole map and infrared spectra. The result showed that:the goal products meet the requirement of the design.Their solubility was more than 50mg/ml(except polyethylene glycol as raw material).They had obviously emission peak between 490～550nm.The results were consistent on the fluorescent dyes which were selected in application of the experimental mentioned. But the fluorescence intensity were weaker than before.One of the goal products had stronger fluorescence intensity which used polyethylene glycol as raw material.But the compound did not dissolve in lubricants.The study also explored the synthesis of other suitable substances.The study synthesized the other intermediate product 4-bromo-N-(4-p-phenoxy-phenyl)-1, 8-naphthalimide which used 4-bromo-1,8-naphthalene dianhydride and 4,4'-diamino diphenyl ether as the raw material.To yield and margin of melting point as indicators optimized the process through single-factor test.that was 4-bromo-1,8-naphthalene dianhydride Without purified and 4,4'-diamino diphenyl ether were one-time fed and their ingredient ratio was 1:1.3.The reaction temperature was 80℃.The reaction time was 6h.The reaction deposited overnight then filtrated it.The yield of the intermediate product 4-bromo-N-(4-p-phenoxy-phenyl)-1,8-naphthalimide was up to 89.2%.