凹凸棒黏土负载型固体酸催化合成乙酰水杨酸

Synthesis of Acetylsalicylic Acid over Attapulgite Supported Solid Acid Catalyst

以凹凸棒黏土(ATP)为载体,制备了负载H^+和AlCl_3的固体酸催化剂(分别标记为H^+/ATP,AlCl_3/ATP),比较了负载前后催化剂对乙酰水杨酸合成反应的催化活性。实验结果表明,固体酸催化剂的活性高于游离酸催化剂,其中AlCl_3/ATP催化剂的活性最高。以AlCl_3/ATP为催化剂催化合成乙酰水杨酸的最佳工艺条件为:催化剂用量为5%(基于水杨酸质量),n(乙酸酐):n(水杨酸)=2.0,反应温度80℃,反应时间30 min;在此条件下,乙酰水杨酸收率达92.5%,纯度为99.5%。用FTIR和~1H NMR表征了产物结构。AlCl_3/ATP催化剂经活化再生重复使用5次后,乙酰水杨酸收率仍可达89.2%,表明AlCl_3/ATP催化剂具有一定的稳定性,可实现再生利用。

Attapulgite（ATP） supported H^＋ and AlCl3 solid acid catalysts（H^＋/ATP and AlCl3/ ATP） were prepared and their catalytic activities for synthesis of acetylsalicylic acid （AA） from salicylic acid and acetic anhydride were compared with the free acids. The results suggested that the solid acid catalysts exhibited higher activity than those of the free acids, especially AlCl3/ATP catalyst. Under the optimum conditions of AlCl3/ATP catalyst mass fraction 5% （based on salicylic acid）, reaction temperature 80 ℃, reaction time 30 min and mole ratio of acetic anhydride to salicylic acid 2.0, the yield and the purity of AA reached 92.5 % and 99.5 % respectively. The synthesized AA was characterized by means of FTIR and ^1H NMR. The AA yield still reached 89.2% after it was regenerated and reused for 5 times.