Radical-scavenging Activity of the Reaction Products of Isoeugenol with Thiol, Thiophenol, Mercaptothiazoline or Mercaptomethylimidazole Using the Induction Period Method
作者:Yoshinori Kadoma、Wakako Kumada、Yuhta Asai、Yoshiaki Sugita、Ichiro Yokoe、Seiichiro Fujisawa
DOI:10.3390/12081836
日期:——
The reaction products in the presence of Lewis acid of isoeugenol (1) with ethanethiol, thiophenol, 2-mercaptothiazoline or 2-mercapto-1-methylimidazole (ISO-S1 – ISO-S-4) were obtained. The radical-scavenging activity of these compounds was investigated using the induction period method for polymerization of methyl methacrylate (MMA) initiated by thermal decomposition of 2,2'-azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO) and monitored by differential scanning calorimetry (DSC). For BPO, the stoichiometric factor (number of free radicals trapped by one mole of antioxidant moiety, n) declined in the order isoeugenol (1.8) > ISO-S-1 (1.6) > ISO-S-2 (1.2 ) > ISOS- 3 (0.9) > ISO-S-4 (0.3), whereas for AIBN, their n values were about 1, except for ISOS- 3 (0.6). The ratio of the rate constant of inhibition to that of propagation (kinh/kp) for BPO declined in the order ISO-S-4 (56) > ISO-S-3 (15) > ISO-S-2 (11) >ISO-S-1 (9) > isoeugenol (8). Similarly, for AIBN the kinh/kp of the reaction products (33-57) was greater than that of isoeugenol (31). The reaction products of isoeugenol with a SH group showed greater inhibition rate constants (kinh) than the parent compound isoeugenol.
在路易斯酸存在下,异丁香酚(1)与乙硫醇、苯硫酚、2-巯基噻唑啉或2-巯基-1-甲基咪唑(ISO-S1-ISO-S-4)的反应产物。使用诱导期法研究了这些化合物的自由基清除活性,该方法用于甲基丙烯酸甲酯(MMA)的聚合,由2,2'-偶氮二异丁腈(AIBN)和过氧化苯甲酰(BPO)的热分解引发,并通过差示扫描量热法(DSC)监测。对于BPO,化学计量因子(一摩尔抗氧化剂捕获的自由基数量,n)的下降顺序为异丁香酚(1.8)> ISO-S-1(1.6)> ISO-S-2(1.2)> ISOS- 3(0.9)> ISO-S-4(0.3),而对于AIBN,其n值约为1,ISOS- 3除外(0.6)。对于BPO,抑制速率常数与传播速率常数(kinh/kp)之比按ISO-S-4(56)> ISO-S-3(15)> ISO-S-2(11)>ISO-S-1(9)>异丁香酚(8)