[试验]Schiemann反应合成氟苯（英文）？ Solutions B PhNH 3 Cl 2.115 mol/L PhNH 3 Cl 16.4338g, H 2 O 40mL, HCl(conc. aq) 20mL C NaNO 2 4.890mol/L NaNO 2 10.1222g, H2O 30mL D NaBF 4 4.793mol/L NaBF 4 15.6696g, H 2 O 30mL Consumption B 30mL, 0.06345mol PhNH 3 Cl C 14.3mL, 0.06980mol NaNO 2 D 13.2mL, 0.06345mol NaBF 4 Procedure 1. Diazotization A conical flask contains 30mL B, is equiped with a magnetic stirrer and an ice bath, adjust the bath temperature below 5°. Then add 14.3mL C dropwisely within 15 minutes, drop ice pieces every 5 minutes in order to keep the temperature below 10°. After the adding complete, stir the solution for 7 minutes, and pour in 13.2mL D at once. A layer of light yellow laminar crystals(diazonium fluoroborate) appear. Then stir for another 15 minutes. Filter the precipitates by suction, and leach it with 20mL ethanol and 20mL of aether in turn. 3.5912g of light yellow solid is obtaind, with the yield of 29.6%. 2. Decomposition Contain the solid obtained in the last step with a 150mL round bottom flask, which is equiped with a condenser and receving apparatus. Heat on one point near the edge of the solid layer with an small flame (eg. alcohol burner). Withdraw the flame as soon as the reaction is initiated. The reaction proceeds spontaneously and smoothly while the solid is melting, bubbling and white smog generating. After the disappearance of the solid, heat the flask and distill the dark-red liquid residue. 1.1mL of colourless, benzene-smelled liquid(fluorobenzene) is obtained, with the yield of 62.8%. The total yield over two steps is 18.6%.查看更多
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