Abstract: In order to explore high-performance polymer modified by orderly hydroxy group,the synthesis method of the key intermediates,hydroxyterephthalic acid monomethyl esters(α-MHT and β-MHT),was studied for preparating new AB-type monomers.The theory and reaction mechanism were discussed in different position esterification and mono-hydrolysis,and a current synthesis and purification technology of terephthalic acid mono-esters with unsymmetrical introduction of hydroxy group was established.The results showed that methyl 2-hydroxy-4-carboxy benzoate(α-MHT)was high-selectivity synthesized by di-esterification of hydroxyterephthalic acid(HTA)with methanol in the presence of SOCl₂ as promoter,then mono-hydrolysis reaction of the di-ester in alkaline solution,the total yield was up to 76%,and methyl 3-hydroxy-4-carboxybenzoate(β-MHT)was directly prepared by mono-esterification of HTA with methanol under sulfuric acid catalysis,with yield nearly 70%.At the same time the synthesis technology and reaction mechanism were effectively applied to preparing 2,6-dihydroxyterephthalic acid mono-ester compounds:alpha-mono methyl ester(α-MDHT)and beta-monomethyl ester(β-MDHT).

Key words: hydroxyterephthalic acid monomethyl esters, high-selectivity synthesis, esterification and mono-hydrolysis, dihydroxyterephthalic acid monomethyl esters

摘要： 为满足羟基有序改性高聚物的需要,研究了制备AB型新单体所需关键中间体——羟基对苯二甲酸单甲酯的合成方法。探讨了不同位置酯化和双酯单水解的理论和反应规律,建立了一种通用于非对称取代对苯二甲酸单酯的合成和分离纯化技术。结果表明:以羟基对苯二甲酸(HTA)为起始原料,先经氯化亚砜作用下的甲醇双酯化,再经碱性水溶液中的单水解反应,高选择性地合成了2-羟基-4-羧基苯甲酸甲酯(α-MHT),总收率76%以上;而HTA硫酸催化甲醇直接单酯化则制得3-羟基-4-羧基苯甲酸甲酯(β-MHT),收率近70%。 同时在2,6-二羟基对苯二甲酸(DHTA)单酯化合物α-单甲酯(α-MDHT)和β-单甲酯(β-MDHT)的合成中得到应用。

关键词: 羟基对苯二甲酸单甲酯, 高选择性合成, 酯化和单水解, 二羟基对苯二甲酸单甲酯