Institute of Functional Molecules, Shenyang University of Chemical Technology, Shenyang 110142, China.
School of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
Molecules. 2020 Nov 30;25(23):5637. doi: 10.3390/molecules25235637.
The stability of the suspension system of the two crystal forms of pyraclostrobin is evaluated using multiple light technology, and the adsorption performance of polycarboxylate dispersant on the surface of two different crystalline pyraclostrobin particles is compared in combination with XRD, FTIR, XPS, and SEM from the microscopic view. The adsorption kinetics and thermodynamics studies of 2700 on the surfaces of different crystalline forms of pyraclostrobin particles show that the adsorption process of 2700 on the surfaces of pyraclostrobin crystal forms II and IV conform to pseudo-second-order kinetic adsorption model. The a values for crystal forms II and IV are 12.93 and 14.39 kJ∙mol, respectively, which indicates that both adsorption processes are physical adsorption. The adsorption models of 2700 on the surfaces of pyraclostrobin crystal forms II and IV are in accordance with Langmuir adsorption isotherms. The values of crystal forms II and IV are negative and the values are positive at different temperatures. Therefore, the adsorption processes are spontaneous and accompanied by entropy increase. The results of this study provide an important theoretical basis for the selection of polycarboxylate dispersants in the suspension of pyraclostrobin. This study also provides a reference for the research of polycrystalline pesticide suspension concentrate.
采用多重光散射技术评价吡唑醚菌酯两种晶型悬浮剂的稳定性，结合 XRD、FTIR、XPS 和 SEM 从微观角度对比了多羧酸分散剂在两种不同晶型吡唑醚菌酯颗粒表面的吸附性能。2700 在不同晶型吡唑醚菌酯颗粒表面的吸附动力学和热力学研究表明，2700 在吡唑醚菌酯晶型 II 和 IV 表面的吸附过程符合准二级动力学吸附模型。晶型 II 和 IV 的 a 值分别为 12.93 和 14.39 kJ·mol，表明两个吸附过程均为物理吸附。2700 在吡唑醚菌酯晶型 II 和 IV 表面的吸附模型均符合 Langmuir 吸附等温线。晶型 II 和 IV 的 值均为负值，且在不同温度下 值均为正值。因此，吸附过程是自发的，伴随着熵的增加。本研究为吡唑醚菌酯悬浮剂中多羧酸分散剂的选择提供了重要的理论依据。本研究也为多晶农药悬浮剂的研究提供了参考。
