Castanheiro José
MED-Instituto Mediterrâneo para a Agricultura, Ambiente e Desenvolvimento, Departamento de Química, Escola de Ciências e Tecnologia, Universidade de Évora, 7000-671 Évora, Portugal.
Polymers (Basel). 2021 Nov 13;13(22):3924. doi: 10.3390/polym13223924.
Esterification of caprylic acid with methanol was performed over chitosan with sulfonic acid groups, as a catalyst, at 60 °C. The sulfonic acid groups were introduced into chitosan (CH) by using chlorosulfonic acid. Catalysts were characterized by scanning electron microscopy (SEM), elemental analysis, thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and acid-base titration. Catalytic activity increased with the amount of sulfonic acid groups present on chitosan. The 4-CH-SOH catalyst (chitosan with sulfonic acid groups-sample 4 prepared) showed the highest activity of all materials. The esterification of caprylic acid with methanol was optimized using a 4-CH-SOH catalyst. Under optimized reaction conditions, it was found that, at 60 °C, with 0.2 g of catalyst loading and with a molar ratio methanol to caprylic acid equal 1:95, a caprylic acid conversion of about 83%, after 4 h could be obtained. Catalytic stability of the 4-CH-SOH material was evaluated through consecutive batch runs. After the second batch, the catalytic activity stabilized.
以含磺酸基团的壳聚糖为催化剂，在60℃下进行辛酸与甲醇的酯化反应。通过使用氯磺酸将磺酸基团引入壳聚糖（CH）中。采用扫描电子显微镜（SEM）、元素分析、热重分析（TGA）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和酸碱滴定对催化剂进行表征。催化活性随壳聚糖上磺酸基团的数量增加而提高。4-CH-SOH催化剂（制备的含磺酸基团的壳聚糖-样品4）在所有材料中表现出最高活性。使用4-CH-SOH催化剂对辛酸与甲醇的酯化反应进行了优化。在优化的反应条件下，发现在60℃、催化剂负载量为0.2 g、甲醇与辛酸的摩尔比为1:95时，4小时后辛酸转化率约为83%。通过连续批次运行评估了4-CH-SOH材料的催化稳定性。第二批之后，催化活性稳定下来。
