微波辐照对松香与丙烯酸加成反应产物酸值的影响

研究了微波对松香与丙烯酸发生Diels-Alder加成反应的促进作用,并通过FT-IR、紫外和HPLC对产物进行分析,确认主要产物即为目标产物。结果表明,微波可有效地加速反应。在35 g松香,7.2 mL丙烯酸加成反应体系中,微波辐照下常压反应90 min,或在密闭压力罐中反应 5 min,反应基本完成。产物的酸值远高于常规加热反应8 h所得产物。常规加热法制备丙烯酸松香时,增加反应时间、升高反应温度均有利于产物酸值的提高。而微波加热反应体系,加压体系中最佳微波功率是640 W,较高的功率和更长的反应时间反而导致产物酸值降低。

Studies on the Diels-Alder Reaction of Rosin with Acrylic Acid under Microwave Irradiation

The Diels-Alde addition reaction of rosin with acrylic acid under microwave irradiation has been investigated. The products have been verified with FT-IR, UV and HPLC. The results show microwave irradiation can effectively accelerate the reaction, which completed within 90 min for open system or 5 min for the sealed system in the addition reaction system of 35 g rosin with 7.2 mL acrylic acid. Acid values of the products under microwave irradiation are much higher than that with routine heating for 8 hours. Long reaction time and high temperature are favorable to increase of acid values of products in the normal heat method for preparation of acrylated rosin. The optimal microwave power is 640 W in microwave hest and pressure system. Excessive microwave power and long irradiation time are adverse to increase of acid values of products.