Ozonolysis of quinoline and quinoline derivatives in a Corning low flow reactor

Abstract

Efficient ozonolysis of quinoline, electron deficient 8-nitroquinoline, and electron rich 6-methoxyquinoline is conducted in a Corning low flow reactor (Corning LFR) with recycling. The conversions of quinoline and 8-nitroquinoline from single-pass experiments were 75.6 and 52.4%, respectively. Upon successive oxidative work-up in a batch reactor, pyridine-2,3-dicarboxylic acid was obtained in 72.7 and 24.7% yields from the ozonolysis products of quinoline and 8-nitroquinoline, respectively. The recycling increased the overall conversions to 95.2 and 76.9%, respectively. For 6-methoxyquinoline, the conversion from the single-pass experiment, 45.2%, was increased to 73.5% with recycling under a higher liquid flow rate and substrate concentration for ozonolysis. Experimental results, conversions, residence time distribution (RTD), and the overall mass transfer coefficient are included in reactor models to determine the rate constants for ozonolysis. Predictions with the rate constants for quinoline, 8-nitroquinoline, and 6-methoxyquinoline show good agreement with the experimental results for different recycle ratios and concentrations of ozone and substrates.