Research On The Ammoximation Of 2,3-butanedione Over Titanium Silicalite Sieves

Diacetyldioxime is an important chemical reagent.Diacetyldioxime can be used in the analysis and determination of metal ions as chelating agents,analytical reagents,redox indicators and chromatographic an alytical reagents and so on.The method for synthesis of diacetyldioxime in industry mainly adopt hydroxylamine method to produce diacetyldioxime,which is synthesized by butanone,ethanol,nitrite and hydroxylamine sodium sulfonate.Firstly,the ethyl nitrite is synthesized with ethanol reacts and nitrous acid in the existence of sulfuric acid.In the next place,Hydrochloric acid as catalyst,the 2,3-Butanedionemonoxime is synthesized with ethyl nitrite and methyl ethyl ketone.Conclusively,the reaction of hydroxylamine sulfonic acid sodium with 2,3-Butanedionemonoxime was produced under the condition of heating to produce diacetyldioxime.However,the synthesis method of diacetyldioxime in industry has many disadvantages,such as difficult separation of products,easy corrosion of raw materials and explosive materials and so on.Therefore,it is necessary to develop a new way for synthesizing diacetyldioxime.Since the synthesis of titanium silicon molecular sieve,because of the titanium silicon molecular sieve and H₂O₂ system not only has the selective oxidation of various organic compounds but also shows good catalytic performance in the reaction of cyclohexanone,hydroxylation of phenol and epoxidation of olefins,titanium silicon molecular sieve have industrialized.The successful application of titanium silicalite molecular sieve in cyclohexanone oxime reaction provides a theoretical and practical support for the synthesis of diacetyldioxime.However,the research on the ammoximation of 2,3-butanedione over titanium silicalite sieves has not been reported.In this paper,hydrogen peroxide was used as oxidant,TS-1、Ti-MOR and Ti-MWW was used as catalysts,The effect of reaction conditions was studied on the synthesis of diacetyldioxime on the 2,3-butanedione ammoximation in the existence of titanium silicalite sieves.The reaction conditions include the amount of catalyst and2,3-butanedione,reaction time and temperature,the amount of solvent and so on.The texture and structural properties of TS-1,Ti-MWW and Ti-MOR were characterized by using X-ray diffraction（XRD）,DRS UV-vis,nitrogen-adsorption,FT-IR spectroscopy,spectroscopyscanning electron microscopy（SEM）and surface contact angle and so on,and the nexus was researched between the structure and performances of the catalysts.The primary results are as follows:（1）The appropriate reaction temperature of the 2,3-butanedione ammoximation over titanium silicalite sieves is 30℃,the appropriate reaction time is 2.0h and the amount of catalyst of t he preparation of the reaction of butyl ketone is 2.0g.The optimum solvent is ethanol on the ammoximation of 2,3-butanedione over titanium silicalite sieves.（2）The feed ratio of hydrogen peroxide in the process of the synthesis of diacetyldioxime is a continuous feed.The appropriate amount of substance ratio of 2,3-butanedione,ammonia and hydrogen peroxide is 1:3:2.（3）The hydrophobic property of titanium silicalite molecular sieve catalyst TS-1 was stronger than that of titanium silicalite molecular sieve catalyst Ti-MOR and titanium silicalite molecular sieve catalyst Ti-MWW.The catalytic performance of titanium silicalite molecular sieve TS-1 catalyst was higher than that of titanium silicalite molecular sieve Ti-MWW and Ti-MOR on the ammoximation of 2,3-butanedione over titanium silicalite sieves.