JP2515909B2 - Method for producing high-purity monoalkylphosphine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a high-purity monoalkylphosphine, and particularly to reacting a phosphorus trihalide with an alkylhalide in the presence of an aluminum halide. ,
This is hydrolyzed to give dihalogenophosphonyl RP (O) X ₂ ,
However, R represents an alkyl group and X represents a halogen. Got
Then, it relates to a method for producing the monoalkylphosphine by reducing the dihalogenophosphonyl.

High-purity monoalkylphosphine can be obtained by MOCVD (Metalor
It is useful as a raw material for epitaxial growth by the ganic Chemical Vapor Deposit-ion) method or the like.

[Conventional technology]

Gallium-phosphorus, indium-phosphorus, etc., a single crystal composed of phosphorus and the periodic table, Group III element is useful as a semiconductor, as a method for obtaining the epitaxy of such a single crystal semiconductor, organometallic vapor phase Chemical growth methods are being developed. Organic phosphorus compounds have recently attracted attention as a phosphorus raw material for this purpose [eg, Journal of Crystal Growth (J. Cry. Growth), 77 (1986) p11].

Further, among organic phosphorus compounds, monoalkylphosphine is often used because carbon is less mixed into crystals.

As a method for synthesizing this monoalkylphosphine, reduction of phosphonyl dichloride with lithium aluminum hydride or sodium metal 2RPCl ₂ + LiAlH ₄ → 2RPH ₂ + LiAlCl ₄ Reduction of dialkyl phosphonates and phosphonyl chloride with lithium aluminum hydride The reaction of phosphine and olefin PH ₃ + R = RPH ₂ + R ₂ PH + R ₃ P is known.

Of these methods, various compounds having boiling points close to each other are by-produced, and thus isolation and purification are difficult, and it is difficult to obtain high-purity monoalkylphosphine. Another method is that the starting phosphonyl dichloride is an unstable compound, it is difficult to separate the starting alkyl halide and phosphonyl dichloride from the starting phosphonyl dichloride, and aluminum, zinc, etc. used as the starting material. Due to the inclusion of impurities from the above metal, it is extremely difficult to obtain high-purity monoalkylphosphine even by this method.

By the way, in the above method, the reduction of dialkyl phosphonate produces an alcohol as a by-product, which interacts with the product monoalkylphosphine, and it is extremely difficult to isolate the monoalkylphosphine. On the other hand, in the method of reducing phosphonyl dichloride, hydrogen chloride is generated. However, it is considered that the removal is easy and the production of high-purity monoalkylphosphine is easy. However, conventionally, in this synthesis, the synthesis of the intermediate phosphonyl dichloride was carried out by adding a 2- to 3-fold excess of alkyl halide to an equivalent amount of aluminum trichloride or phosphorus trichloride to form a complex,
A method was used in which an approximately equivalent amount of hydrochloric acid was added to this to hydrolyze, and then the solvent was removed [Journal of Organic Chemistry (J.Ory.Chem.) 16 ,
(1952) p892]. However, this method yields 40-50
%, And it is difficult to separate unreacted alkyl halide and water, and it is extremely difficult to obtain high-purity monoalkylphosphine. Moreover, in this reduction reaction, diethyl ether was used as the reaction solvent [Monatsch., 90 , (195
9), p148], an interaction occurs between the ether of the solvent and the monoalkylphosphine, and the boiling point of the monoalkylphosphine is relatively low, which makes it difficult to completely separate the ether. It was

[Problems to be Solved by the Invention]

The present invention has solved the above problems, and an object of the present invention is to provide a method for producing a high-purity monoalkylphosphine having a purity of 99.99% or more in a high yield.

[Means for solving the problem]

The present invention is directed to reacting a phosphorus trihalide with an alkyl halide in the presence of aluminum halide, hydrolyzing it to give a dihalogenophosphonyl, which is then reduced to give a monoalkylphosphine. In the method for producing, after the dihalogenophosphonyl obtained by the hydrolysis is extracted with an organic solvent having a lower boiling point than the dihalogenophosphonyl, the organic solvent is removed by distillation to 100 ppm or less, and then monoalkyl. A method for producing a high-purity monoalkylphosphine having a purity of 99.99% or more, which comprises reducing dihalogenophosphonyl in the presence of an organic solvent having a boiling point higher than that of phosphine.

The present invention can be applied to any monoalkylphosphine having an alkyl group, but isopropyl, tert-butyl, phenyl and the like, among which, tert-butyl is preferably used in MOCVD and the like, and is particularly preferable.

In the present invention, a method of reacting phosphorus trihalide with an alkyl halide in the presence of aluminum halide, and hydrolyzing this to obtain dihalogenophosphonyl,
For example, the equivalents of aluminum trihalide and trihalide phosphorus, by stirring by adding from 0.5 to 3 times the halogenated ^{_{alkyl, [RPX 3] + [AlX}} 4] - create a complex consisting of hydrochloric acid thereto Is a method of adding and hydrolyzing. As the aluminum trihalide, aluminum trichloride, aluminum tribromide, aluminum triiodide, etc., and as the phosphorus trihalogenide, phosphorus trichloride, phosphorus tribromide, phosphorus triiodide, etc., As the alkyl halide, alkyl chloride, alkyl bromide, alkyl iodide, or the like can be used, and the alkyl group is appropriately selected according to the kind of the intended monoalkylphosphine.

In the present invention, dihalogenophosphonyl is extracted from an aqueous hydrochloric acid solution of the hydrolyzate thus obtained with an organic solvent having a lower boiling point than that of the dihalogenophosphonyl.
As the extraction solvent, any solvent can be used, so long as it has a property of separating from water, dissolves the dihalogenophosphonyl well, and has a lower boiling point than the dihalogenophosphonyl, Preferred are ethers such as diethyl ether and tetrahydrofuran, and alkyl halides such as dichloromethane and chloroform. By providing the extraction step with this extraction solvent,
It is possible to add a large amount of hydrochloric acid to the product that has been hydrolyzed in the vicinity of the equivalent amount and the yield has been lowered, and sufficiently perform the hydrolysis. Further, during this extraction, a larger amount of water to concentrated hydrochloric acid or the like can be added, and preferably 1 to 6 N hydrochloric acid is added. The amount of this extraction solvent used is such that the amount of dihalogenophosphonyl dissolved is the minimum, and no problem is added even if it is added more, but if added in too large a quantity, the operation becomes complicated when the solvent is distilled off. . Therefore, it is preferable that the amount is the minimum amount necessary to dissolve the dihalogenophosphonyl. The extraction solvent may be added either before or after the complex is hydrolyzed with hydrochloric acid, but it is particularly preferably before the decomposition.

The solution containing the dihalogenophosphonyl after the extraction and separation can be dehydrated by adding a dehydrating agent such as anhydrous sodium sulfate or anhydrous magnesium sulfate, if desired.

Next, the solvent is distilled off from the solution containing the dihalogenophosphonyl after the extraction and separation to 100 ppm or less by distillation. The exact reason for this is unknown, but the monoalkylphosphine, which is a product obtained by reducing the dihalogenophosphonyl unless the solvent is removed to 100 ppm or less at this stage, for example, by precision distillation. This is because it is not possible to achieve a purity of 99.9% or higher. This operation is the greatest feature of the present invention. Then, the dihalogenophosphonyl is dissolved in an organic solvent having a boiling point higher than that of the monoalkylphosphonyl and reduced. As this solvent, those having a boiling point higher than that of the monoalkylphosphine by 50 ° C. or more are preferable, and ethers such as dibutyl ether and diphenyl ether are particularly preferable from the viewpoint of solubility of the reducing agent and the like. It is desirable that the concentration of the dihalogenophosphonyl dissolved in this organic solvent be 10 to 40% by weight so that the reduction reaction can proceed smoothly. On the other hand, as the reducing agent, lithium aluminum hydride, metallic sodium, or the like can be used, and the reducing agent is preferably used in an equivalent amount or more with respect to dihalogenophosphonyl. The monoalkylphosphine reduced in this manner can be obtained as a highly pure monoalkylphosphine having a purity of 99.99% or more by distillation separation.

〔Example〕

(Example 1) Phosphorus trichloride 50 g (0.36 mol) and aluminum chloride 48 g
(0.36 mol) in a container, and while cooling with ice, chloride -tert
-Butyl 40 ml (0.36 mol) was added dropwise with stirring. Then, the temperature is raised with stirring, and [t-BuPCl ₃ ] ⁺ [A
lCl _4] ^- to give a complex consisting of. This solid was dispersed with 200 ml of diethyl ether, and 400 ml of 2N hydrochloric acid under ice cooling.
Was added dropwise to decompose the complex. 10 mm of dehydrated ether layer
Distilled under reduced pressure of Hg to remove tert-butylphosphonyl dichloride.
44.3 g was obtained. The crude yield was 70%. A small amount of diethyl ether and -tert-butyl chloride were mixed in this.
Therefore, precision distillation was performed under a reduced pressure of 10 mmHg, and 40.0 g (0.23
White crystals of (mol) were obtained. Diethyl ether in this,
The content of -tert-butyl chloride was 100 ppm or less. 40.0 g of this white crystal was dissolved in 150 ml of di-n-butyl ether, and this was added to a suspension of 17.3 g of LiAlH ₄ in 100 ml of di-n-butyl ether, and the mixture was stirred for 2 hours for reduction and reduced to normal pressure. Distillation was performed to obtain 14.5 g of a colorless transparent liquid having a boiling point of 54 ° C. This contained a small amount of di-n-butyl ether. Repeated precision distillation gave a fraction of 13.0 g (0.14 mol). Di-n-butyl ether in this was 100 ppm or less.

(Comparative Example 1) a complex synthesis, decomposed under the same conditions as in Example 1, without precision distillation the resulting two -tert- chloride Buchiruhosuhoniru, in di -n- butyl ether was reduced with LiAlH _4. Diethyl ether, tert-butyl chloride, and di-n-butyl ether were contained in 16.0 g of the obtained colorless transparent liquid. Although di-n-butyl ether could be reduced to 100 ppm or less by repeated precision distillation, 0.1 wt% or more of -tert-butyl chloride and diethyl ether were recognized.

(Comparative Example 2) Synthesis and purification under the same conditions as in Example, diethyl ether,
40.0 g (0.23 mol) of tert-butylphosphonyl dichloride with tert-butyl chloride below 100 ppm were reduced with LiAlH _{4 in} diethyl ether. The colorless transparent liquid obtained 20.5
A large amount (30% or more) of diethyl ether was contained in g. It was quite difficult to remove diethyl ether even after repeated precision distillation.

〔The invention's effect〕

The present invention as described above, the dihalogenophosphonyl obtained by hydrolysis is extracted with an organic solvent having a lower boiling point than the dihalogenophosphonyl, and then the organic solvent is distilled.
Since it was reduced to 100 ppm or less, and then dihalogenophosphonyl was reduced in the presence of an organic solvent having a higher boiling point than monoalkylphosphine, high-purity monoalkylphosphine with a purity of 99.99% or more was produced in high yield. Has the special effect of being able to

Claims (1)

(57) [Claims] 1. A phosphoryl trihalide is reacted with an alkyl halide in the presence of an aluminum halide, which is hydrolyzed to give a dihalogenophosphonyl, which is then reduced to give a monoalkyl In the method for producing phosphine, after dihalogenophosphonyl obtained by the hydrolysis is extracted with an organic solvent having a lower boiling point than the dihalogenophosphonyl, the organic solvent is removed by distillation to 100 ppm or less, and then monoalkyl. A method for producing a high-purity monoalkylphosphine having a purity of 99.99% or more, which comprises reducing dihalogenophosphonyl in the presence of an organic solvent having a boiling point higher than that of phosphine.