CN112010320A

CN112010320A - Preparation method of B-substituted sodium cyanoborohydride

Info

Publication number: CN112010320A
Application number: CN202010805711.1A
Authority: CN
Inventors: 陈学年; 郭宇; 陈西孟
Original assignee: Henan Normal University
Current assignee: Henan Normal University
Priority date: 2020-08-12
Filing date: 2020-08-12
Publication date: 2020-12-01
Anticipated expiration: 2040-08-12
Also published as: CN112010320B

Abstract

The invention discloses a preparation method of B-substituted sodium cyanoborohydride, which is implemented by reacting sodium cyanoborohydride NaBH under the conditions of no water, no oxygen and normal temperature₃CN solution and BR₃The solution is mixed and reacted to obtain a colorless oily target product B which replaces sodium cyanoborohydride NaBH₃CNBR₃In which NaBH is present₃CN and BR₃The feed molar ratio of (a) is 1:1, R = F, Cl or Br; or under the conditions of no water and no oxygen and normal temperature, the sodium cyanoborohydride NaBH is added₃CN solution and THFBH₂The R solutions are mixed and react to obtain a colorless oily target product B substituted cyano sodium borohydride NaBH₃CNBH₂R, wherein NaBH₃CN and THFBH₂The molar ratio of R charged is 1:1, R = F, Cl or Br. Compared with the prior method, the method has the advantages of high reaction rate, simple operation, low toxicity, harmlessness, safety and reliability.

Description

Preparation method of B-substituted sodium cyanoborohydride

Technical Field

The invention belongs to the technical field of preparation of cyanoborohydride, and particularly relates to a preparation method of B-substituted sodium cyanoborohydride.

Background

Sodium cyanoborohydride is a hydrogen storage material and is a mild reducing agent, and is widely used for the reduction of aldehyde and ketone compounds, particularly the reductive amination of the ketone compounds. Using NaBH₃CN and THFBH₃Reaction to synthesize purer NaBH₃CNBH₃First synthesis of NaBH by Muetterties as early as 1961₃CNBH₃Until 1970, NaBH by Robert c.wade team₃CNBH₃Make into¹¹B NMR, IR, elemental analysis and the like, and determining the structure of the cyanide bridge bond. Except in 1983 that NaBH₃CNBH₂CN was synthesized for the first time, followed by little synthesis of B-substituted sodium cyanoborohydride.

The B substituent group sodium cyanoborohydride can be used as a hydrogen storage material, can also be used as a potential reducing agent, has the reducibility weaker than that of sodium borohydride, and can be used for exploring other applications. Few derivatives of sodium cyanoborohydride are currently on the market, especially sodium cyanoborohydride with cyano as the substituent for cyano bridge B.

Disclosure of Invention

The invention solves the technical problem of providing a preparation method of B-substituted cyano sodium borohydride, which has the advantages of low cost, simple operation, safety, reliability, low toxicity and no harm.

The invention adopts the following technical scheme for solving the technical problems, and the preparation method of the B-substituted cyano sodium borohydride is characterized by comprising the following specific processes: under the conditions of no water and no oxygen and normal temperature, sodium cyanoborohydride NaBH is added₃CN solution and BR₃The solution is mixed and reacted to obtain a colorless oily target product B which replaces sodium cyanoborohydride NaBH₃CNBR₃In which NaBH is present₃CN and BR₃The feed molar ratio of (a) is 1:1, R = F, Cl or Br; or under the conditions of no water and no oxygen and normal temperature, the sodium cyanoborohydride NaBH is added₃CN solution and THFBH₂The R solutions are mixed and react to obtain a colorless oily target product B substituted cyano sodium borohydride NaBH₃CNBH₂R, wherein NaBH₃CN and THFBH₂The molar ratio of R charged is 1:1, R = F, Cl or Br.

Further preferably, the preparation method of the B-substituted cyano sodium borohydride is characterized by comprising the following specific steps: all operations were carried out under nitrogen atmosphere and NaBH was placed in a glove box₃CN is stirred and dissolved in tetrahydrofuran, and NaBH is added₃Adding THFBH into CN solution₂R solution is reacted, wherein NaBH₃CN and THFBH₂The feeding molar ratio of R is 1:1, and the reaction is carried outIn the course of which there is a white substance (BH)₂CN)_nOligomers present, with¹¹BNMR monitors the reaction, judges the reaction end point, when the reaction is completed, a needle filter is used for filtering the solution, solid impurities are removed, filtrate is collected, the filtrate is pumped by a vacuum pump to obtain a colorless oily product, the colorless oily product is white powder at low temperature, n-hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBH₂R。

Further preferably, the preparation method of the B-substituted cyano sodium borohydride is characterized by comprising the following specific steps: all operations were carried out under nitrogen atmosphere and NaBH was placed in a glove box₃CN is stirred and dissolved in tetrahydrofuran, and NaBH is added₃Adding 1mol/L BR into CN solution₃CH (A) of₂Cl₂Solutions or BR₃In diethyl ether, wherein NaBH is added₃CN and BR₃The feeding molar ratio of (1: 1) and reacting until use¹¹B NMR monitoring reaction is finished, after the reaction is completed, the solution is filtered by a needle head type filter, solid impurities are removed, filtrate is collected, the filtrate is dried by a vacuum pump to obtain a colorless oily product, the colorless oily product is white powder at low temperature, normal hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBR₃。

The reaction equation in the preparation method of the B-substituted cyano sodium borohydride is as follows:

compared with the prior art, the invention has the following beneficial effects: compared with the prior method, the method has higher reaction efficiency, simple operation, low toxicity, harmlessness, safety, reliability and lower cost, and finally synthesizes the B-substituted sodium cyanoborohydride NaBH₃CNBH_3-nR_n(n =1 or 3; R = F, Cl or Br), which can be used as a reducing agent and a hydrogen storage material, and provides great convenience for subsequent scientific research.

Drawings

FIG. 1 shows the B-substituted sodium cyanoborohydride NaBH prepared in example 1 of the present invention₃CNBH₂Cl in THF¹¹B liquid nuclear magnetic diagram, which shows that the prepared target product is pure NaBH₃CNBH₂Cl。

Detailed Description

The present invention is described in further detail below with reference to examples, but it should not be construed that the scope of the above subject matter of the present invention is limited to the following examples, and that all the technologies realized based on the above subject matter of the present invention belong to the scope of the present invention.

Example 1

All operations were performed under a nitrogen atmosphere. Weighing a certain amount of NaBH in a glove box₃CN, adding proper amount of tetrahydrofuran, stirring to dissolve, adding NaBH₃Adding a certain amount of THFBH into CN solution₂Cl solution, the molar ratio of the two reactants is 1:1, and white substance (BH) is generated in the reaction process₂CN)_nOligomers appear. By using¹¹BNMR monitors the reaction progress and judges the reaction end point. And after the reaction is completed, filtering the solution by using a needle head type filter, discarding solid impurities, collecting filtrate, and pumping the filtrate by using a vacuum pump to obtain a colorless oily product. The colorless oily product is white powder at low temperature, or a certain amount of normal hexane can be added at low temperature for washing for 3 times, and the product is purified to obtain NaBH₃CNBH₂Cl。

Example 2

All operations were performed under a nitrogen atmosphere. Weighing a certain amount of NaBH in a glove box₃CN, adding a proper amount of tetrahydrofuran, stirring to dissolve the tetrahydrofuran, and slowly adding 1mol/L of BBr₃CH (A) of₂Cl₂4mL of the solution. The reaction is carried out until use¹¹The reaction was monitored by B NMR for completion. And after the reaction is completed, filtering the solution by using a needle head type filter, discarding solid impurities, collecting filtrate, and pumping the filtrate by using a vacuum pump to obtain a colorless oily product. The colorless oily product is white powder at low temperature, a certain amount of normal hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBBr₃。

Example 3

All operations were performed under a nitrogen atmosphere. To a 10mL schlenk reaction flask containing magnetons was added 0.252g NaBH₃CN, adding a proper amount of tetrahydrofuran, stirring to dissolve the tetrahydrofuran, removing the schlenk reaction bottle out of the glove box after sealing by a plug, and slowly adding 1mol/L BCl₃CH (A) of₂Cl₂4mL of the solution was stirred at room temperature, a small amount of insoluble matter was removed by filtration, and the filtrate was concentrated to remove the solvent to give a colorless oily product. The colorless oily product is white powder at low temperature, a certain amount of normal hexane is added at low temperature for washing for 3 times, and the product is purified to obtain NaBH₃CNBCl₃。

Example 4

All operations were performed under a nitrogen atmosphere. To a 10mL schlenk reaction flask containing magnetons was added 0.252g NaBH₃CN, adding a proper amount of tetrahydrofuran, stirring to dissolve the tetrahydrofuran, sealing by a plug, removing the schlenk reaction bottle out of the glove box, and slowly adding 1mol/L BF₃4mL of the resulting ether solution was stirred at room temperature, a small amount of insoluble matter was removed by filtration, and the filtrate was concentrated to remove the solvent to give a colorless oily product. The colorless oily product is white powder at low temperature, a certain amount of normal hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBF₃。

The foregoing embodiments illustrate the principles, principal features and advantages of the invention, and it will be understood by those skilled in the art that the invention is not limited to the foregoing embodiments, which are merely illustrative of the principles of the invention, and that various changes and modifications may be made therein without departing from the scope of the principles of the invention.

Claims

1. A preparation method of B-substituted cyano sodium borohydride is characterized by comprising the following specific steps: under the conditions of no water and no oxygen and normal temperature, sodium cyanoborohydride NaBH is added₃CN solution and BR₃The solution is mixed and reacted to obtain a colorless oily target product B substituted cyano sodium borohydrideNaBH₃CNBR₃In which NaBH is present₃CN and BR₃The feed molar ratio of (a) is 1:1, R = F, Cl or Br; or under the conditions of no water and no oxygen and normal temperature, the sodium cyanoborohydride NaBH is added₃CN solution and THFBH₂The R solutions are mixed and react to obtain a colorless oily target product B substituted cyano sodium borohydride NaBH₃CNBH₂R, wherein NaBH₃CN and THFBH₂The molar ratio of R charged is 1:1, R = F, Cl or Br.

2. The method for preparing B-substituted sodium cyanoborohydride according to claim 1, comprising the following steps: all operations were carried out under nitrogen atmosphere and NaBH was placed in a glove box₃CN is stirred and dissolved in tetrahydrofuran, and NaBH is added₃Adding THFBH into CN solution₂R solution is reacted, wherein NaBH₃CN and THFBH₂The feeding molar ratio of R is 1:1, and white substances (BH) exist in the reaction process₂CN)_nOligomers present, with¹¹BNMR monitors the reaction, judges the reaction end point, when the reaction is completed, a needle filter is used for filtering the solution, solid impurities are removed, filtrate is collected, the filtrate is pumped by a vacuum pump to obtain a colorless oily product, the colorless oily product is white powder at low temperature, n-hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBH₂R。

3. The method for preparing B-substituted sodium cyanoborohydride according to claim 1, comprising the following steps: all operations were carried out under nitrogen atmosphere and NaBH was placed in a glove box₃CN is stirred and dissolved in tetrahydrofuran, and NaBH is added₃Adding 1mol/L BR into CN solution₃CH (A) of₂Cl₂Solutions or BR₃In diethyl ether, wherein NaBH is added₃CN and BR₃The feeding molar ratio of (1: 1) and reacting until use¹¹Monitoring the reaction by B NMR, filtering the solution with a needle filter after the reaction is complete, discarding solid impurities, collecting the filtrate, and vacuum-drying the filtrate to obtain a colorless oily productThe colorless oily product is white powder at low temperature, normal hexane is added at low temperature for cleaning for 3 times, and the product is purified to obtain NaBH₃CNBR₃。