摘要
以对羟基苯甲酸(PHB)和乙酸酐(Ac2O)为原料,醋酸(HAc)为溶剂,考察浓硫酸和杂环化合物催化合成4-乙酰氧基苯甲酸(PABA),反应物配比为羟基苯甲酸∶乙酸酐∶醋酸=1∶1.05∶0.5,确定最佳催化剂加入量、反应时间和反应温度。结果表明,浓硫酸为催化剂时,最佳反应时间2 h,反应温度100℃,催化剂加入量为PHB质量的4%,产率67%;杂环化合物P为催化剂时,最佳反应温度80℃,反应时间2 h,催化剂加入量为PHB质量的0.3%,产率99.8%。杂环化合物比浓硫酸对PABA合成有更好的催化活性,反应条件温和,具有较好的工业化应用前景。
In this paper the efficiency of two catalysts, concentrated sulfuric acid and heterocyclic compound P, has been compared during the synthesis of p-Acetoxybenzoic acid （PABA） with p-Hydroxyhenzoic acid （PHB） and acetic anhydride as raw materials. Thus the added amount of catalyst, the reaction time and the reaction temperature were optimized for the reaction mixture of p-hydroxy benzoic acid, acetic anhydride and acetic acid with a loading ratio of 1： 1：0.5. It has been found that the most suitable reaction time, reaction temperature, catalyst addition （respect to PHB weight） and productivity of PABA could be 2 h, 100 ℃ , 4% , 67% or 2 h, 80 ℃ , 0.3% , 99.8% when using concentrated sulfuric acid or heterocyclic compound P as catalyst, respectively. Therefore, heterocyclic compound P showed a better catalytic activity compared to concentrated sulfuric acid, with which the synthesis of PABA could be carried out under a relatively loose reaction conditions, and promised a great application foreground.
出处
《合成技术及应用》
2014年第2期5-10,共6页
Synthetic Technology & Application
