A kind of preparation technology of sodium tert-butoxide

Background and overview

Sodium tert-butoxide, also known as sodium tert-butoxide, white to yellow powdery solid, molecular formula: C4H9NaO, molecular weight: 96.10, density: 1.104g/cm3, boiling point: 180 ℃, stable performance under normal temperature and pressure, storage should be under the protection of inert gas Keep the container tightly closed, store it in a cool and dry place, and avoid contact with strong reducing agents, moisture, air, acids and other substances. Sodium tert-butoxide can be used as organic synthesis intermediates and pharmaceutical intermediates, or as a strong base, and is widely used in chemical, pharmaceutical, pesticide and organic synthesis reactions such as condensation reactions, rearrangement reactions or ring-opening reactions. Therefore, sodium tert-butoxide is a very important intermediate in fine chemicals, pesticides, pharmaceuticals and other industries.

Preparation^【1】

Preparations before the reaction: add water to the reactor and heat it to 30°C, stir and clean for 15 minutes, and drain; repeat the above steps, after two cleanings are completed, open the steam valve, and dry at 92°C for 35 minutes After the reactor drying operation is completed, Replace the reactor with nitrogen three times, keep the reactor at positive pressure for 10 minutes, turn the upper vacuum pump to make the vacuum degree of the system reach 0.098MPa, replace it with ammonia water three times, remove the vacuum with nitrogen each time, and flush it to positive pressure with nitrogen for the last time;

feeding reaction: Put the solvent xylene into the reaction kettle, and put sodium metal into the reaction kettle, and control the mass ratio of xylene to sodium metal to be 1:18.5. After the feeding is completed, turn on steam to heat, and start the reaction kettle when the temperature reaches 97°C. Stir, the initial stirring rate is 22r/min, and depending on the melting of the sodium lumps, gradually increase the stirring speed. After the sodium lumps are completely melted, the fastest stirring rate will be reached. The fastest stirring rate is 85r/min, and the temperature will continue to rise to 128 while stirring. , when the sodium block is completely melted, it will be in a state of reflux; Under the protection of inert gas, put sodium hydride into the reactor to completely dissolve the sodium hydride in the molten sodium metal. The added amount of sodium hydride is 0.04 times the mass of the sodium metal. Add tert-butanol dropwise to the reactor. The amount of butanol added is 4.2 times the mass of sodium metal, keep reflux, and the dropping time is controlled at 2.2h. After the dropping is completed, the reaction temperature is 132, react for 10.5h, stop stirring and observe whether there is sodium Chips, if the reaction is not complete, continue to heat the reaction until no sodium chips and no reflux are observed to confirm the completion of the reaction; Obtain the product: After the reaction is completed, filter to remove sodium hydride, and recover xylene by distillation under normal pressure, and the time for distillation under normal pressure is 3.8h; After the atmospheric distillation is over, start the vacuum pump to perform vacuum distillation. The vacuum distillation time is 38min. After the reaction vacuum reaches -0.098Mpa, turn on nitrogen to unload the vacuum, turn off the steam, turn on the circulating water to cool down, and continue to charge during the cooling process. Nitrogen maintains the positive pressure of the reactor. After the temperature of the reactor drops to 35°C, samples are taken from the reactor for testing. After the testing is qualified, the product is discharged and packaged to obtain the product sodium tert-butoxide.

references

[1] CN112851472,2021,A