2,6-二氯苯甲醛卤素交换氟化动力学研究

研究了以硝基苯为溶剂,相转移催化剂作用下的2,6-二氯苯甲醛的卤素交换氟化反应。在催化机理与反应动力学方面进行了相关探讨。在n(氟化钾)∶n(2,6-二氯苯甲醛)∶n(四苯基溴化)∶n(丙酮-呋喃冠醚)=4∶1∶0.1∶0.05的最佳工艺条件下,通过对433,443,453,463 K 4个温度下实验数据的分析,得出了各步的反应速率常数,并最终求得其第1步和第2步的反应活化能分别为4.57×104J/mol和3.53×104J/mol;指前因子分别为4.50×105h-1和1.08×104h-1,为进一步深入研究提供了必要的动力学数据。

Kinetics of halogen-exchange fluorination of 2,6-dichlorobenzaldehyde

Under the conditions of phase transfer catalysis and taking nitrobenzene as solvent,the halogen-exchange fluorination of 2,6-dichlorobenzaldehyde using KF as fluorination agent was studied.The kinetics was investigated and the reaction rate constants were obtained under the optimum conditions of n(KF) ∶n(2,6-dichlorobenzaldehyde) ∶n(Ph4PBr) ∶n(acetone-furan crown ether)=4 ∶1 ∶0.1 ∶0.05 and through the analysis of the experimental data at 433,443,453 and 463 K.The results show that the activation energy of the first and the second step is respectively 4.57×104 J/mol and 3.53×104 J/mol,the preexponential factor is 4.50×105 h-1 and 1.08×104 h-1 respectively.Thus a reliable kinetics data can be obtained for further research.