• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.744-748
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• 2010

2,3,4,5-Tetrafluorobenzoic acid, an important intermediates of fluoroquinolone antibiotics, was synthesized from tetrachloride phthalic anhydride through imidation, fluorination, hydrolysis and decarboxylation. The effects of phase transfer catalyst on imidation and fluorination reaction and the effects of surfactants on the hydrolysis reaction were studied, respectively. Experimental results showed that the imidation reaction time was greatly reduced in the presence of a phase transfer catalyst, hexadecyltrimethyl, resulting in imidation yield as high as 98.2%. The fluorination yield reached 81.3% when tetrabutylammonium bromide was chosen as a phase transfer catalyst. The hydrolysis reaction time was also decreased by adding hexadecyltrimethyl while increasing the yield to 88.6%. In the post-processing, the sublimation method was used to purify the product, and ideal effect was obtained. In the decarboxylation reaction, tetrafluoride phthalic acid was obtained by decarboxylation in the solvent of tri-n-butyl amine and decarboxylation yield reached 81.6%. Compared with the literature method, the overall reaction time of the improved method decreased from 53 h to 20.5 h and the total yield increased from 47.3% to 57.4%.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.40-44
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• 2014

For the purpose of development of an effective process for purified CHMI particles, a series of experimental researches on the synthesis of CHMI from CHMAIE, purification and precipitation of CHMI were preformed. It is turned out that n-heptane reflux imidation is more beneficial than toluene put-out imidation not only to the synthesis but to the precipitation of CHMI. By washing the synthetic CHMI with cold n-heptane twice, purified CHMI with 99.7% purity could be obtained at the cost of 11.7% weight loss. And CMHI particles were effectively prepared by spouting molten CHMI through the spiral nozzle with 3 mm diameter under the pressure of $1.5{\sim}2.0kg/cm^2$.