| High-performance polymers are more and more required with the society’s progress. Polyethylenenaphthalate (PEN) exhibits better performances in various aspects than polyethyleneterephthalate (PET), and can be widely used in packaging, electronics, thin film, fiber and so on.2,6-Naphthalenedicarboxylic acid (2,6-NDA), as a key intermediate chemicals for many functional polymers (such as PEN), is often synthesized by using naphthalene compound with two substituent groups as the precursors. However, complicated synthesis routes and high synthesis cost limit the wide utilization. Therefore, it is expected to find an efficient and economic synthesis route for the precursor of2,6-NDA.In this paper,2-methyl-6-acylnaphthalene was synthesized in a liquid phase system from2-methylnaphthalene with Cat as catalyst, homemade acylating reagent R as acylating agent, organic solvent A as solvent. The influence of reaction conditions on the acylation is studied. The products are characterized by mass spectrometry and infrared structure, respectively, proving that the product is2-methyl-6-acylnaphthalene. Based on the yield and purity of the product, the optimized experiment conditions are obtained as follows:the molar ratio of2-methylnaphthalene/acylating reagent R/Cat is W2, adding temperature is TD℃to TE℃, reaction temperature is T4℃, reaction time is t4h. The production yield is92%along with the product purity of81.7%.The acylation reaction process has been further optimized in this paper. The effect of solvent amount on the acylation and the influence of inert gas atmosphere in vacuum distillation on the2-methyl-6-acylnaphthalene yield and purity are also discussed. The results show that the acylation reaction yield and product purity has little change when the weight ratio of organic solvent A to Cat is4.73to5.67. The yield and purity of products is improved by0.9%and0.3%, respectively, in the acylation distillation process under inert gas atmosphere. When the organic solvent A after distill is reused as the reaction solvent, the yield and purity of2-methyl-6-acylnaphthalene is increased by1.5%and0.4%, respectively. |
