A kind of preparation method of lithium trialkyl borohydride

A technology of trialkyl boron and trimethoxy aluminum hydride, which is applied in the field of preparation of trialkyl lithium borohydride, can solve the problems of long production cycle, difficult solid-liquid separation, and many impurities in tetrahydrofuran solution, and achieve crystal grain The effects of long crystallization time, high purity of solution products, and difficulty in solid-liquid separation

Active Publication Date: 2022-08-05
沧州临港星辰化工有限公司
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  • Abstract
  • Description
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Problems solved by technology

, using lithium aluminum hydride as one of the reactants. Lithium aluminum hydride has strong activity. The feeding process has high requirements on technology and equipment, and there are great safety hazards
The reaction releases a large amount of heat, and lithium aluminum hydride must be added dropwise very slowly, and the whole process must be carried out in an ice-water bath, with a long production cycle and complicated process; the by-product is triethylenediamine aluminum hydride complex, and the reaction speed Fast, the crystal grains formed are small, which makes solid-liquid separation difficult, and the final product tri-sec-butyl lithium borohydride tetrahydrofuran solution contains many impurities and the solution is turbid. That is, the preparation of tri-sec-butyl lithium borohydride by this process has a long production cycle, Problems such as low yield and low content, and great safety hazards, high requirements for equipment and other defects

Method used

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  • A kind of preparation method of lithium trialkyl borohydride
  • A kind of preparation method of lithium trialkyl borohydride
  • A kind of preparation method of lithium trialkyl borohydride

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[0023] The present invention discloses a preparation method of lithium trialkylborohydride, which can be realized by those skilled in the art by referring to the content of the present invention, combining relevant principles of organic chemistry, and appropriately improving process parameters. It should be particularly pointed out that all similar substitutions and modifications apparent to those skilled in the art are deemed to be included within the scope of the present invention. The application of the present invention has been described through the preferred embodiments, and it is obvious that relevant persons can make changes or appropriate changes and combinations of the methods and applications described herein without departing from the content, spirit and scope of the present invention, so as to realize and apply the present invention. Invention technology.

[0024] For a better understanding of the invention and not to limit the scope of the invention, all numbers ...

Embodiment 1

[0027] Example 1: Preparation of lithium triethylborohydride

[0028] Step A: Preparation of the reaction solution: In the ingredient A tank, 115.2 g (0.9 mol) of lithium trimethoxyaluminum hydride was dissolved in tetrahydrofuran ether solution to form 1.3 L of a 0.7 mol / L lithium trimethoxy aluminum hydride solution; in the ingredient B tank, 88.2g (0.9mol) of triethylborane was dissolved in tetrahydrofuran to form 1L of 0.9mol / L triethylborane solution;

[0029] Step B: Condensation reaction: add 0.3 L (23%) of the lithium trimethoxyaluminum hydride solution prepared in step A into the reaction kettle, stir and control the temperature to 21-23°C, then, follow the steps in Table 1. Dropping scheme, the remaining solution in batching tank A and the solution in batching tank B are added dropwise to the reaction kettle respectively, the whole dropping process is about 130min, after the dropwise addition is completed, the reaction is stirred for 0.5h, and then allowed to stand f...

Embodiment 2

[0032] Example 2: Preparation of Lithium Triisobutyl Borohydride

[0033] Step A: Preparation of the reaction solution: In the ingredient A tank, 115.2 g (0.9 mol) of lithium trimethoxyaluminum hydride was dissolved in tetrahydrofuran ether solution to form 1.3 L of a 0.7 mol / L lithium trimethoxy aluminum hydride solution; in the ingredient B tank, 163.8g (0.90mol) of triisobutylborane was dissolved in tetrahydrofuran to form 1L of 0.9mol / L triisobutylborane solution;

[0034] Step B: Condensation reaction: add 0.26 L (20%) of the trimethoxyaluminum hydride lithium hydride solution prepared in step A into the reaction kettle, stir and control the temperature to 21-23° C. Add scheme, the remaining solution in batching tank A and the solution in batching tank B are added dropwise to the reaction kettle respectively, and the whole dropwise addition process is about 125min. Separation to obtain a supernatant, which is a solution of triisobutyl lithium borohydride in tetrahydrofur...

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Abstract

The invention provides a preparation method of lithium trialkyl borohydride, comprising the following steps: Step A: respectively preparing a solution of lithium trimethoxyaluminum hydride in tetrahydrofuran ether and a solution of trialkylborane in tetrahydrofuran; Step B: condensation reaction : Add 20%-25% of the lithium trimethoxyaluminum hydride solution prepared in step A into the reaction kettle, stir and control the temperature to 21-23°C, and then according to a specific dripping scheme, the remaining ingredients in batching tank A are added. and the solution in the batching tank B were added dropwise to the reaction kettle respectively. After the dropwise addition was completed, the reaction was stirred for 0.5-2h, and then allowed to stand for 0.5-2h; solid-liquid separation was obtained to obtain the supernatant, which is trialkylboron The tetrahydrofuran ether solution of lithium hydride; the molar yield of tris(hydroxymethyl)aminomethane obtained by the present invention is more than 96%, the product content reaches more than 99.0%, and the quality is stable.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and relates to a preparation method of lithium trialkyl borohydride. Background technique [0002] Trialkylborohydrides are very powerful nucleophilic reducing agents capable of rapidly and quantitatively cleaving cyclic ethers, reducing halides, alcohols, sulfonates, epoxides and activated alkenes to desired products. Hindered and highly hindered trialkylborohydrides have very good steric control in the reduction of cyclic and bicyclic ketones, unmatched by any other reducing agent. [0003] Chinese patent CN107446003A discloses a preparation method of tri-sec-butyl lithium borohydride, the equation is [0004] (C 4 H 9 ) 3 B+LiAlG 4 +C 6 H 12 N=Li(C 4 H 9 ) 3 BH+AllH 3 ·C 6 H 12 N. , Lithium aluminum hydride is used as one of the reactants. Lithium aluminum hydride has strong activity, and the feeding process requires high technology and equipment, and there is a greater...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F5/02
CPCC07F5/027
Inventor 车瀛照陈兆前
Owner 沧州临港星辰化工有限公司
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