Study On The Synthesis Of 2, 6-Dimethylnaphthalene By Shape Selectivity

2,6-dimethylnaphthalene (2,6-DMN) is a potentially useful raw material for production of polyethylene naphthalate (PEN), polybutylene naphalate(PBN) and liquid crystalline polymers (LCP) with superior properties. How to industrialize the process of producing 2,6-DMN is getting more and more studied in the world recently. However, PEN have heretofore been too expensive to expand its market complete because of few effective processes for the 2,6-DMN commercialization. Most of these studies focused on looking for new catalysts with high activity and selectivity and optimizing the reaction conduction to raise the yield.Therefore, in this paper, the process for preparing 2,6-DMN by methylation of methylnaphthalene over AlClx/HY and AlClx/HY-U zeolite catalysts is employed. The effects of reactions conductions on reaction results were studied. The researching content was as follows:1. When AlClx/HY zeolite be used as catalyst, the effects of the ratio of 2-methylnaphthalene to tetramethyl benzene, catalyst concentration, reaction temperature and reaction time on the conversion (based on 2-methylnaphthalene), yield and selectivity (both based on 2,6-DMN) were discussed. In addition, by orthogonal experiment, the optimum reaction conditions were determined at the same time. The optimum reaction conditions : the molar ratio of 2-methylnaphthalene and tetramethyl benzene =1:1, reaction temperature was 400℃.2. The effects of AlClx/HY-U zeolite treated by ultrasonic was used as catalyst was studied. AlClx/HY-U zeolite considerably enhanced the selectivity of 2,6-DMN. The reaction result showed that the conversion of 2-MN was about 33.41%, the selectivity of 2,6-DMN.was abou 33.84%.3. The effects of the frequency of ultrasonic and the insonation time by ultrasonic on the activity and the selectivity of AlClx/HY-U was studied. The optimum reaction conditions : the frequency of insonation time on HY:40kHz;the frequency of insonation time on loading AlCl3:59kHz;the time of insonation time on HY:40min;the time of insonation time on loading AlCl3:60min。4. The AlClx/HY-U zeolite was analysed. The result was both the granularity and...