Using coal tar distillate as the starting material, a novel high‐purity 2,6‐naphthalenedicarboxylic acid (2,6‐NDA) preparation method was developed. Firstly, the 2,6‐dimethylnaphthalene (2,6‐DMN) precursor was separated by successive vacuum distillation, melt crystallization, and solvent crystallization from the 250–270 °C fraction of the coal tar distillate. Then, over Co‐Mn‐Br as catalysts, oxidation of 2,6‐DMN was carried out in acetic acid to produce crude 2,6‐NDA with molecular oxygen. By high‐temperature hydrogenation, the crude 2,6‐NDA was further purified to obtain high‐purity 2,6‐NDA. From the coal tar distillate to pure 2,6‐NDA, the operation parameters and reaction conditions of each process were optimized and evaluated, indicating that the proposed 2,6‐NDA synthesis method has great potential for industrial application to create cheap feedstock in viable yields.

中文翻译：

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用煤焦油馏分制备高纯度的2,6-萘二甲酸

以煤焦油馏出物为原料，开发了一种新的高纯度2,6-萘二甲酸（2,6-NDA）制备方法。首先，通过连续的真空蒸馏，熔融结晶和溶剂结晶从250-270°C的煤焦油馏分中分离出2,6-二甲基萘（2,6-DMN）前体。然后，以Co-Mn-Br为催化剂，在乙酸中氧化2,6-DMN，生成带有分子氧的粗品2,6-NDA。通过高温加氢，将粗制的2,6-NDA进一步纯化以获得高纯度的2,6-NDA。从煤焦油馏分到纯的2,6-NDA，对每个过程的操作参数和反应条件进行了优化和评估，表明拟议的2