4-chloro-2-fluoronitrobenzene is a vital farming intermediate approximately, such as synthetic low toxicity, broad spectrum, ultra-high efficiency weedicide fluthiacetmethyl. The existing synthetic method has a great majority of 2, and 4-dichloronitrobenzene is a starting raw material, so prepare 4-chloro-2-fluoronitrobenzene through the halogen replacement(metathesis)reaction.
General procedure: Potassium fluoride (KF), 2,4-dichloronitrobenzene (DCNB) and solvent are added to a Schott tube or reactor, which is subjected to a nitrogen atmosphere. Subsequently, the reaction mixture is heated at the specified temperature for 4 hours. Upon completion of the reaction, the reaction mixture is filtered and analyzed by gas chromatography.
Example 1: In this example, the following reaction conditions were used: a molar ratio of 2,4-dichloronitrobenzene (DCNB) to potassium fluoride (KF) of 1:2 (the actual amount used was 1.05 times the theoretical amount), and tetramethylammonium chloride (TMAC) in an amount of 0.04 times the molar amount of DCNB. The reaction was carried out at 170 °C for 4 h, using a Schott tube as the reaction vessel. Numbers in parentheses indicate the molar ratio relative to the substrate (DCNB).
[1] Patent: US2004/24238, 2004, A1. Location in patent: Page 5
[2] Patent: US2004/24238, 2004, A1. Location in patent: Page 6
[3] Patent: US2004/24238, 2004, A1. Location in patent: Page 5
[4] Patent: US2004/24238, 2004, A1. Location in patent: Page 5
[5] Patent: US2004/24238, 2004, A1. Location in patent: Page 5
