2-Chloro-4-fluorotoluene synthesis

Yield:452-73-3 81.8%

Reaction Conditions:

Stage #1:3-chloro-p-toluidine with hydrogen fluoride at 5 - 15; for 5 h;
Stage #2: with sodium nitrite at -5 - 80;Temperature;

Steps:

6 Example 6
1L reactor (equipped with a condenser, the gas phase outlet diameter is1/6 to 1/5 of thediameter of the kettle), and the temperature is lowered to 20 °C or lower. Under stirring, 424 g (21.2 mol, 20 eq) of anhydrous hydrogen fluoride is added, and the temperature is lowered after the feed is completed. To 5 °C or less,150 g (1.059 mol, 1 eq) of 3-chloro-4-methylaniline wasadded dropwise, and the temperature was controlled in the range of 5 to 15 °C, and the addition was completed in about 3 hours, and the temperature was kept for 2 hours.After thecompletion of theheat preservation, thetemperature was lowered to 5 °C or less, and 73.1 g of sodium nitrite (1.06 mol, 1 eq) was added in portions, and the reaction temperature was controlled within the rangeof-5 to 15 °C, and the mixture was added forabout 4 hours, and the heat was kept for 1 hour.After the heat preservation, the temperature of the reaction kettle is programmed (strictly controlling the heating rate:when thetemperature is in the range of 0 to 20 °C, the temperature is raised by 0.5 to 1 °C per hour,when the temperature is in the range of 20 to 80 °C, the temperature is raised by 1 to 2 °C per hour), and the temperature is raised to 80 °C and keep warm for2h.After the heat preservation is completed, the temperature is lowered to 30 to 35 °C, and the layers are separated. The organic layer is neutralized to a pH of 7 to 8 by a dilute alkali, and steam distillation is carried out. The organic layer is 141 g at room temperature, and the purity of the gas chromatographic detection is 93.4%. The distillation obtained 125.1 g of qualified product, the yield was 81.8%, and the purity of 2-chloro-4-fluorotoluene obtained by gas chromatography was 99.9%.

References:

Liaoning Tian Yu Chemical Co., Ltd.;Jiangsu Lianhua Technology Co., Ltd.;Lianhua Science And Technology (Yancheng) Co., Ltd.;Lianhua Technology Co., Ltd.;Zhao Liqiang;Yang Zongsheng;Yuan Weiwei;Yin Xiaoxu;Du Yong;Yang Wenlong;Wang Yang;Li Shanshan CN108569948, 2018, A Location in patent:Paragraph 0035-0059

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