Preparation method of triethyl boron

Abstract

The invention discloses a preparation method of triethyl boron, which comprises the following steps: putting boron trifluoride diethyl etherate, magnesium powder, part of long-chain ether and a small amount of iodine into a three-necked flask, preparing bromoethane and the residual long-chain ether into a solution, putting the solution into a constant-pressure dropping funnel, taking out the solution, introducing the solution into a nitrogen vacuum pipeline, simultaneously inserting an ultrasonic probe, putting the three-necked flask into an ice-water bath, and reacting for 2-4 hours; placing a magnetic stirrer capable of heating; wherein the left side of the three-necked flask is connected with nitrogen, the middle of the three-necked flask is connected with a constant-pressure dropping funnel, the right side of the three-necked flask is connected with a condenser, the condenser is continuously connected with a sand core filter ball, another empty three-necked flask is used below the filter ball to receive filtrate, finally, the filtrate is subjected to reduced pressure distillation to obtain triethyl boron, and the obtained fraction is used for receiving the fraction at 44-47 DEG C by using metered tetrahydrofuran or n-hexane. According to the method, key synthesis conditions and a control method in the synthesis process of the triethyl boron are optimized, the synthesis yield of the triethyl boron is further improved, the post-treatment process is greatly simplified, and reliable technical support is provided for industrialization of the triethyl boron.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a synthesis technology of triethylboron. Background technique [0002] Triethylboron, which can be mixed with triethylaluminum as a two-component igniter for rocket propulsion systems, is also widely used in organic synthesis. It plays an indispensable role in the fields of aerospace, chemical industry, and organic synthesis. However, the preparation of triethylboron has always been difficult. Triethylboron was the first to react directly with boron ester / boron halide through organometallic compounds; however, the reaction time of this organometallic route was lengthy, spanning 2h to 24h, and the final yield was up to 95%; and the complicated prefabrication process led to There are too many dangerous experimental steps, and a slight inappropriateness in each link will seriously affect the final yield, which deviates from the modern experimental concept of high efficien...

AI Technical Summary

Problems solved by technology

However, the preparation of triethylboron has always been difficult

Triethylboron was the first to react directly with boron ester / boron halide through organometallic compounds; however, the reaction time of this organometallic route was lengthy, spanning 2h to 24h, and the final yield was up to 95%; and the complicated prefabrication process led to There are too many dangerous experimental steps, and a slight inappropriateness in each link will seriously affect the final yield, which deviates from the modern experimental concept of high efficiency, science and safety

However, there are many obvious deficiencies in the traditional ultrasonic synthesis of triethylboron, resulting in a final yield of no more than 80%.

Its disadvantages are: 1. Ultrasound alone can greatly shorten the reaction time and increase the yield, but ignores the importance of mechanical stirring; 2. There are defects in the control of reaction temperature; There is a lot of interference in the purification; ④The post-treatment process is complicated, and it needs to be distilled at atmospheric pressure first, and then distilled under reduced pressure

The above four deficiencies will seriously affect the final yield of triethyl boron, so it needs to be improved urgently to meet the criteria of efficient and safe experiments

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