Some problems that arise during the preparation of sodium ethoxide
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When preparing sodium ethoxide, we cut the sodium into very fine and thin slices with a kitchen knife and add it to the reaction kettle. Something went wrong: A large amount of hydrogen was generated, and the sodium, which was a safety issue, failed to reflect and sank to the bottom of the reactor, blocking the discharge bottom valve. Is there a better solution?
Modify the discharge valve of the reaction kettle to adopt a spiral type, and use the sodium hydroxide process to avoid the use of metallic sodium.
It is important to pay attention to the safety of the hydrogen generated when preparing sodium ethoxide by the sodium method, especially the safety issues caused by non-open flames such as static electricity. The venting should be kept away from unsafe places. When cutting sodium metal, you should consider minimizing the chance and time of contact with air. Once it is oxidized, it cannot react with ethanol and will naturally sink to the bottom. Of course, you must also pay attention to the low solubility of sodium ethoxide in ethanol. Add as much absolute ethanol as possible to the reaction. If your sodium ethoxide does not have high requirements for free base, you can consider using sodium hydroxide to prepare it.
The produced hydrogen can be led to high altitude to be discharged. If the precipitation problem is as mentioned above, please look at the equipment or process instead.
Changing the discharging method can prevent sodium from sinking to the bottom, such as pressing the material with positive pressure in the system. Can you tell me the size of your reactor and the amount of feed? It would be best to send a diagram of the equipment. In fact, the more specific the question, the better it will be for everyone to discuss!
Well, that's it. After the reaction is completed, DMF is added to evaporate part of the ethanol-DMF mixture, and the final result is a solution of sodium ethoxide in DMF. For alkali, DMF should be decomposed.
Oh well. In this way, a 100% reaction kettle, 67% ethanol, and 2 kg of sodium are first cut and placed in petroleum ether. The ethanol is heated to a certain temperature and the sodium is added. It is not easy for sodium to sink to the bottom. After analysis, it is found that sodium metal is oxidized in the air and has a high density. When added, it will sink to the bottom directly. Just effectively avoid oxidation and control the feeding rate. It's still ok. What everyone said makes sense.
Our company uses about 10 tons of metallic sodium every month, so I am familiar with the reaction of sodium. To solve your problem in preparing sodium ethoxide, use the following method to see if it works: As for the problem of sinking to the bottom, sodium generally does not oxidize to this extent as you said. The reason why it sinks to the bottom may be that the reaction is incomplete due to the thickening of the system when the reaction reaches a certain point. The solution is to add a large amount of ethanol and then evaporate the excess ethanol after the reaction. It depends on the concentration of sodium alkoxide required for your reaction. 2. The problem of hydrogen: You can solve the safety problem by using a water-sealed device at the exhaust port, or you can blow it with nitrogen during the reaction, but the location of the exhaust port must be open to prevent hydrogen from gathering.
Use sodium hydroxide to react with ethanol. Sodium hydroxide can be dissolved in ethanol.