JP2807101B2 - Method for producing high-purity alkyl phosphine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an alkyl phosphine. In particular, the present invention relates to MOCVD (Metalorga
The present invention relates to a method for producing a high-purity alkylphosphine used as a raw material when forming a compound semiconductor thin film by a (nic Chemical Vapor Deposition) method.

[0002]

2. Description of the Related Art Group III-V compound semiconductor thin films such as indium-phosphorus are useful as materials for manufacturing electronic devices. As a method of forming a compound semiconductor thin film, MBE (Molecular Beam Epitaxy), halide
CVD, MOCVD, MOMBE (Metalorganic Molecular Beam E
pitaxy). Among them, MOCVD or MO
MBE is a crystal growth method that has been attracting attention as its frequency of use has increased because it is not necessary to maintain a high vacuum inside the crystal growth system, it is easy to exchange raw materials, and maintenance is easy.

However, when producing a group III-phosphorus compound semiconductor by these methods, phosphine, which is a highly toxic hydride of phosphorus, is used as a raw material of the phosphorus compound. I am worried. Therefore, in recent years, alkylphosphines have been proposed in place of phosphine as a phosphorus material. In particular, monoalkylphosphines, which have two hydrogen atoms, have less carbon contamination into semiconductor thin films and are attracting attention as phosphine alternative materials with reduced toxicity. . (For example, J. Crystal Growt
h. 77 (1986) 11)

As a method for synthesizing alkyl phosphine,
Alkyl halogeno-reduction with lithium aluminum hydride or sodium phosphate compound _{2RPCl 2 + LiAlH 4 → 2RPH 2} + LiAlCl 4 RPCl 2 + 4Na ─ → (+ H 2 O →) RPH 2 + 2NaCl + 2NaOH the phosphonous acid dialkyl or phosphonic acid dialkyl aluminum hydride Reduction by lithium R ¹ P (OR ² ) ₂ + LiAlH ₄ → R ¹ PH ₂ Reaction of phosphine with olefin PH ₃ + C _n H _2n → C _n H _{2n + 1}・ PH ₂ + (C _n H _{2n + 1} ) ₂・PH + (C _n H
_{2n + 1} ) ₃ P are known. (R, R ¹ , R ² : alkyl group)

[0005]

Among the methods for synthesizing these alkyl phosphines, the method based on the reduction of an alkyl halogeno compound is mainly used as a conventional reducing agent mainly in terms of yield in terms of lithium aluminum hydride (LiAl
H ₄ ) is used. However, when an alkylhalogenoline compound is reduced using lithium aluminum hydride, an alkyl halide is generated as a side reaction product due to the strong reducing power of lithium aluminum hydride,
This is incorporated into the resulting alkyl phosphine.

[0006] Further, lithium aluminum hydride is usually produced using diethyl ether as a solvent. Therefore, when alkylphosphine, which is a reduction product, has a low boiling point, diethyl ether is mixed in the product, and these compounds are converted into a product. Residuals in the solution hindered purification of the alkylphosphine. In addition, lithium aluminum hydride is a highly active and dangerous reagent that is highly flammable and explosive, and is difficult to handle. As a reducing agent, sodium borohydride can be used, but the yield of alkylphosphine obtained by this method is low.

The inventors of the present invention have studied a reducing agent to replace lithium aluminum hydride. As a result, when sodium bis (2-methoxyethoxy) aluminum is used, almost no alkyl halide is generated in the reduction reaction. Further, the present inventors have found that a high-purity alkylphosphine can be obtained in a high yield without containing diethyl ether. Accordingly, an object of the present invention is to obtain a high-purity alkyl phosphine substantially free of alkyl halide and diethyl ether.

[0008]

That is, the present invention is characterized in that sodium bis (2-methoxyethoxy) aluminum hydride is used as a reducing agent in a reaction for reducing an alkylhalogenoline compound to synthesize an alkylphosphine. Is a method for producing an alkylphosphine.

The present invention can be applied to the production of an alkyl phosphine having any alkyl group, and the MOCV
The method is applied to the production of monoalkyl phosphines such as isopropyl, tert-butyl, phenyl and the like as raw materials when forming a compound semiconductor thin film by the method D, and monoalkyl phosphines with few impurities can be produced.

The present invention also relates to phosphonyl dihalide (RPX ₂ ) or phosphonyl dihalide (RP (O)
Production of monoalkyl phosphines by reduction of alkyl dihalogenoline compounds such as X ₂ ), phosphinyl halide (R ₂ PX) or phosphinyl halide (R
_The present invention can be applied to any production of dialkylphosphine by reduction of a dialkylhalogenoline compound such as (2P (O) X).

Since sodium bis (2-methoxyethoxy) aluminum is usually commercially available as a 70% toluene solution, it is desirable to distill off toluene by heating before the reduction reaction. The amount of the reducing agent to be added is preferably at least three times the equivalent of the amount of the alkylhalogenoline compound from the viewpoint of the reaction rate. As the reaction solvent, a high boiling ether solvent is preferable. In particular, when synthesizing a low-boiling alkyl phosphine, it is preferable to use a high-boiling ether such as dibutyl ether.

After completion of the reaction, the alkylphosphine is extracted into the organic layer by adding hydrochloric acid, and can be separated and recovered. The concentration and amount of hydrochloric acid to be added are preferably as large as 6N hydrochloric acid from the viewpoint of the reaction yield, but from the viewpoint of reducing alkyl halide contamination, it is preferable that the amount of added salt be as small as possible.

[0013]

EXAMPLES Example 1 All operations were performed under an inert atmosphere. 323 g of a 70% toluene solution of sodium bis (2-methoxyethoxy) aluminum hydride is placed in a flask at 100 ° C., 5 mmH
g Toluene was removed by heating under reduced pressure for 3 hours. After returning to room temperature, 100 ml of dibutyl ether was added. Separately, 66 g (0.42 mol) of tert-butyldichlorophosphine (tert-BuPCl ₂ ) dissolved in 200 ml of dibutyl ether was added to a dropping funnel and dropped to sodium bis (2-methoxyethoxy) aluminum hydride cooled to about -10 ° C. did. After completion of the dropwise addition, the mixture was heated and stirred at 60 ° C. for 1 hour. After returning to room temperature, the mixture was cooled again to about -10 ° C and 900 ml of a 6N hydrochloric acid aqueous solution was gradually added. The reaction solution became cloudy, and when further added, completely separated into two layers. The organic phase of the upper layer was extracted, anhydrous sodium sulfate was added, and the mixture was allowed to stand overnight.
The filtrate was distilled to give 21 g of a colorless liquid. ³¹ P-NMR and
^{From 1} H-NMR, this liquid was found to be tert-butylphosphine (tert-B
uPH ₂ ). The yield was 56%, and quantitative analysis by gas chromatography revealed that diethyl ether was 7 ppm or less and tert-butyl chloride was 7 ppm or less.

Example 2 All operations were performed under an inert atmosphere. Sodium bis (2-methoxyethoxy) aluminum hydride (NaAlH
₂ (OC ₂ H ₄ OCH ₃ ) ₂ ) 396 g of a 70% toluene solution was placed in a flask, and toluene was distilled off under heating at 100 ° C., 5 mmHg and 3 hours. After returning to room temperature, 100 ml of dibutyl ether
Was added. On the other hand, tert-butyldichlorophosphonyl (tert-BuP (O) C
l ₂ ) 80 g (0.46 mol) was placed in a dropping funnel and added dropwise to sodium bis (2-methoxyethoxy) aluminum hydride cooled to about -10 ° C. After completion of the dropwise addition, the mixture was heated and stirred at 60 ° C. for 1 hour. After returning to room temperature, the mixture was cooled again to about -10 ° C and 900 ml of a 6N hydrochloric acid aqueous solution was gradually added. The organic phase was extracted, anhydrous sodium sulfate was added, and the mixture was allowed to stand overnight. Then, the anhydrous sodium sulfate was filtered off, and the filtrate was distilled to obtain 28 g of a colorless liquid. This than ³¹ P-NMR and ¹ H-NMR liquid was identified as tert- butylphosphine (tert-BuPH _2). 68% yield,
When determined by gas chromatography, the content of diethyl ether was 7 ppm or less, and that of tert-butyl chloride was 7 ppm.
It was below.

Comparative Example 1 All operations were performed under an inert atmosphere. 24 g of lithium aluminum hydride was placed in a flask containing 100 ml of dibutyl ether, and 200 ml of dibutyl ether was added and dissolved in tert-butyldichlorophosphonyl (tert-BuP (O) Cl ₂ ).
75 g (0.43 mol) was added dropwise using a dropping funnel. After completion of the dropwise addition, the mixture was heated and stirred at 70 ° C. for 1 hour. After returning to room temperature,
The mixture was cooled again to -10 ° C and 900 ml of a 6N hydrochloric acid aqueous solution was gradually added. The reaction solution was separated into two layers. The upper organic phase was extracted, anhydrous sodium sulfate was added, and the mixture was allowed to stand overnight. Then, anhydrous sodium sulfate was filtered off and distilled to obtain 20 g of a colorless liquid. ³¹
This liquid was identified as tert-butylphosphine by P-NMR and ¹ H-NMR. Yield 52%, quantitatively determined by gas chromatography, 500 ppm diethyl ether, tert-
Butyl chloride was mixed in at 120 ppm.

Comparative Example 2 All operations were performed under an inert atmosphere. 41 g of sodium borohydride is suspended in 50 ml of diglyme, and the suspension is suspended at about -10
After cooling to ℃, 30 g of tert-butyldichlorophosphine (tert-BuPCl ₂ ) dissolved in diglyme was added dropwise using a dropping funnel. After completion of the dropwise addition, the mixture was heated and stirred at 70 ° C. for 1 hour.
After returning to room temperature, the mixture was cooled again to -10 ° C, and 150 ml of dodecane was added as an extraction solvent.
0 ml was added. After extracting the organic phase of the upper layer, adding anhydrous sodium sulfate and allowing to stand overnight, the anhydrous sodium sulfate was filtered off and distilled, and the obtained tert-butylphosphine was 0.8 g.
(5% yield).

[0017]

According to the present invention, by using sodium bis (2-methoxyethoxy) aluminum hydride as a reducing agent for alkylhalogenoline compounds, organic impurities such as alkyl halides and ethers can be removed in high yield. A high-purity alkylphosphine for producing a semiconductor thin film, which is substantially not contained, can be obtained.

────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Koichi Nakamura 3-17-35 Niisominami, Toda City, Saitama Japan Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) C07F 9 / 50

Claims (1)

(57) [Claims] 1. A method for producing an alkylphosphine, which comprises using sodium bis (2-methoxyethoxy) aluminum hydride as a reducing agent in a reaction for synthesizing an alkylphosphine by reducing an alkylhalogenoline compound.