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

Abstract

Under the conditions of phase transfer catalysis and nitrobenzene as the solvent, the halogen-exchange fluorination of 2,6-dichlorobenzaldehyde using KF as fluorinating 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 temperatures of 433 K, 443 K, 453 K and 463 K. The results illustrated the activation energy of the first and the second step is 4.57 × 10⁴ J·mol^-l and 3.53 × 10⁴ J·mol^-1, respectively. The pre-exponential factor is 4.50 × 10⁵ h^-1 and 1.08 × 10⁴ h^-1, respectively. Thus a reliable kinetics data could be obtained for further research.

Keywords

2,6-dichlorobenzaldehyde / halogen-exchange fluorination / phase transfer catalysis / kinetics