A preparation method of Phenyllithium Solution, comprising the following steps:
1) Under the protection of inert gas, add sodium-lithium alloy and n-butyl ether into the system, and stir to obtain a sodium-lithium alloy dispersion; the mass fraction of sodium in the sodium-lithium alloy is 1-6%, the present invention Substituting metallic lithium in sodium-lithium alloys can promote the initiation of the reaction. The dosing mass ratio of sodium-lithium alloy and n-butyl ether is 1:10～30. The reaction process of sodium-lithium alloy and bromobenzene has relatively high requirements on moisture and air (such as oxygen and carbon dioxide). Before production, the air in the entire production system is replaced with an inert gas, and the inert gas is argon. , The density of argon is higher than that of air, and the anhydrous and oxygen-free conditions are easy to control, and the inert gas needs to be dried before use. The reaction between bromobenzene and sodium-lithium alloy is usually difficult to initiate, the success rate is low, and it is very sensitive to temperature. The reaction stops when the temperature is lower than 10 °C. Once the reaction stops, even heating and dropwise addition of bromobenzene cannot be rescued. At the same time, the temperature cannot be higher than 30°C, otherwise a large amount of coupling products will be produced.
(2) at 10～30 ℃, add bromobenzene dropwise to the sodium-lithium alloy dispersion liquid obtained in step (1) under stirring, control the temperature of the system at 10～30 ℃, after the dropping is completed, the insulation reaction is processed to obtain benzene base lithium solution. Dissolving bromobenzene in n-butyl ether and then dropping it into the system, the mass percentage concentration of the obtained bromobenzene n-butyl ether solution is 40-60%. In terms of active ingredients, the dosage of bromobenzene in the bromobenzene-n-butyl ether solution is 10 to 20 times the quality of the sodium-lithium alloy in the system. The dropwise addition of bromobenzene is completed within 6 to 8 hours. The purity of the product is closely related to the dropping rate of bromobenzene. If the dropping rate is too fast, a coupling product will be produced. During the dropwise addition of bromobenzene, the concentration of the product phenyllithium should be monitored in real time, and the dropwise addition of bromobenzene should be stopped when the product concentration does not increase. After the dropwise addition of benzene is completed, the reaction is continued for 1 to 2 hours under heat preservation.
