4-(-5氨基-6-羟基-2-苯并噁唑基)苯甲酸盐的合成、性能及应用

系统地研究了AB型新单体4-5-氨基-6-羟基-2-苯并口恶唑基)苯甲酸盐（ABAS）的合成新方法、性能及其在聚对亚苯基苯并二口恶唑制备中的应用。结果表明：采用以4-(5-硝基-6-羟基-2-苯并-口恶唑基)苯甲酸甲酯（MNB）为原料，经碱性水解及水解液直接还原合成高纯度ABAS的新技术，具有工艺简练、污染少及经济性良好等特点，总收率达84%，它经历以水解物4-(5-硝基-6-羟基-2-苯并口恶唑基)苯甲酸的二钾盐为中间物质的加氢还原、酸析反应历程;对于95%以下纯度的MNB采用水解分离后再还原的两步法合成工艺，也能获得近99%纯度的ABAS;经¹ H NMR、¹³C NMR和FT-IR等确认为ABAS后，TG测得起始热分解温度为290℃，具有优异的热稳定性和抗氧化性; 99%纯度的ABAS在玻璃反应器中以聚合13 h最后升温至230℃的方式可制得特性黏数大于15 dl·g^-1的PBO树脂，具有完全等当比缩聚、操作安全、易工业化等技术特征。

Synthesis, characteristics and application of 4-(5-amino-6-hydroxybenzoxazole-2-yl)benzoic acid salt

Novel synthesis, characteristics and application of new AB-PBO monomer 4-(5-amino-6-hydroxybenzoxazole-2-yl) benzoic acid salt（ABAS）were studied The results showed that ABAS was one pot synthesized from methyl 4-(5-nitro-6-hydroxybenzoxazole-2-yl)benzoate (MNB) with a yield of 84% and purity of 99% via alkali hydrolysis and reduction, which had the advantages of simple procedure, low pollution and cost savingThe mechanisms of alkali hydrogenation and acidification with 4-(5-nitro-6-ydroxy benzoxazole-2-yl)benzoic acid dipotassium salt as intermediate were proposedWith MNB below 95% purity, the ABAS approaching 99% purity could also be prepared by the two step method of hydrolysis and reductionThe ABAS was identified with ¹ H NMR, ^13C NMR, FT-IRIts initial decomposition temperature was measured to be 290℃, and it had excellent thermostability, oxidation resistance and outstanding storage stabilityUsing ABAS of 99% purity, PBO resin was easily prepared by self- polycondensation for 13 h at 230℃ as end polymerization temperature in glassware and its intrinsic viscosity was more than 15 dl·g^-1. The procedure had the characteristics of equi molar polycondensing group, safe operation , easy industrialization and etc.