氟代脱硝法合成间氟苯甲醛

SYNTHESIS OF META-FLUOROBENZALDEHYDE BY FLUORODENITRATION

报道了以间硝基苯甲醛为反应底物,喷雾干燥氟化钾(SD-KF)为氟离子源,一步合成间氟苯甲醛的氟代脱硝反应,研究了氟化剂用量、反应时间、溶剂等因素对反应的影响。结果表明,在间硝基苯甲醛用量25 mmol、n(间硝基苯甲醛):n(SD-KF):n(四苯基溴化鳞):n(邻苯二甲酰氯)=10:40:1:10、V(聚四乙二醇二甲醚)=0.25 mL、V(硝基苯)=25 mL、t=5h、θ=210℃条件下,反应转化率、选择性分别为70.5%和24.7%,间氟苯甲醛收率可达17.4%。反应也可在微波中进行,在投料比相同条件下反应2h,此时反应转化率、选择性及产物收率分别为74.3%、20.5%、15.2%。

Fluorodenitration of m-nitrobenzaldehyde with SD-KF in the presence of phthaloyl chloride was studied. The optimum reaction conditions were found as follows： n（m-nitrobenzaldehyde） ： n（SD- KF） ： n （Ph4PBr） ： n（PDC） = 10 ： 40 ： 1 ： 10, 0.25 mL tetraethylene glycol dimethylether, PDC as trapping agent for NOz, 210 ℃, reaction time 5 h and nitrobenzene as solvent. Under these conditions, 17.4% m-fluorobenzaldehyde was obtained with 70.5% conversion and 24.7% selectivity. The fluorodenitration reaction could also be carried out under microwave irradiation with 74.3% conversion, 20.5% selectivity and 15.2% yield.