JPS6217004A - Preparation of germane - Google Patents

Abstract

PURPOSE:To prepare germanes having low content of by-product economically advantageously by prepg. germanes from halogenated germanes using a specified hydrogenating agent contg. alkyl aluminum monohalide. CONSTITUTION:In the preparation of germanes from halogenated germanes using a hydrogenating agent prepd. by adding alkyl aluminium halide sufficient to transform above 90mol% trialkyl aluminum to dialkyl aluminium monohalide to a mixture consisting of alkyl aluminium hydride and trialkyl aluminium. A hydrogenating agent prepd. to contain below 0.1wt% metallic Al basing on the amt. of alkyl aluminium hydride in the hydrogenating agent is used. Suitable halogenated germanes to be used are germanium tetrachloride, hexachloro digermance, octachloro trigermane, etc.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for producing germanes.

More specifically, the present invention relates to a method for producing germanes from halogenated germanes using a specific hydrogenating agent.

BACKGROUND ART Methods for producing germanes from halogenated germanes using a hydrogenating agent such as lithium aluminum hydride, sodium hydride, or alkyl aluminum hydride are already well known. We have already proposed a method for obtaining germane compounds in good yield using a mixture of alkyl aluminum hydride and trialkylaluminium, which are industrially easily available (Japanese Patent Application No. 59-075045).

Problems to be Solved by the Invention Using a mixture of alkyl aluminum hydride and trialkylaluminium, which can be obtained from the process of industrially producing trialkylaluminium,
We have found that when germanes are produced according to the method of -073045, germanes can be obtained in extremely high yields, but as a problem, by-products such as alkylgermanes are produced.

Removal of these by-products requires a large amount of energy and equipment, and it has been desired to develop a method for producing germanes that produces fewer by-products.

Means for Solving the Problems The inventor of the present invention has conducted extensive research to solve the above-mentioned problems, and has completed the present invention.

That is, the present invention uses a hydrogenating agent in which an amount of alkyl aluminum halide or aluminum chloride is added to a mixture of alkyl aluminum hydride and trialkyl aluminum in an amount sufficient to convert 90 mole or more of trialkyl aluminum into dialkyl aluminum monohalide. In the method for producing germanes from halogenated germanes, the amount of metallic aluminum relative to the alkyl aluminum hydride in the hydrogenating agent is 0.
．． This is a method for producing germanes, characterized by using germanes with a content of 1 wt% or less.

The germanes produced in the present invention are germanium hydrides such as monogermane, digermane, and trigermane, which are produced from the following corresponding germane halides.

The halogenated germane, which is a raw material in the present invention, is a compound represented by the general formula GeX2n+2.

In this formula, X is a halogen atom, but some of the four substituents may be hydrogen atoms, alkoxy groups,
Although n is 1, 2 or more, the larger n becomes, the more difficult it becomes to handle. The alkoxy group may be a methoxy group, ethoxy group, etc., and the halogen may be chlorine or bromine.

Particularly preferred halogenated germanes include germanium tetrachloride, hexachlorodigermane, and octachlorotrigermane.

It is.

R is an alkyl group having 1 to 10 carbon atoms, such as ethyl group, n-propyl group, or isobutyl group. Among the compounds represented by the above general formula, examples of compounds that are industrially easily available are diethyl aluminum hydride and diisobutyl aluminum hydride.

Trialkylaluminum in the present invention is a compound represented by the general formula R5Al.

R is an alkyl group having 1 to 10 carbon atoms, such as ethyl group, n-propyl group, or isobutyl group.

In mixtures of alkyl aluminum halides and trialkylaluminums that are available on an industrial scale, the R's of the alkyl groups are usually the same, but two or more R's may be contained. Further, the weight ratio of the alkyl aluminum hydride and trialkyl aluminum hydride in the mixture is usually 3 to 8:2.

Industrially, the above mixtures are available as intermediates in the production process of alkyl aluminum. That is, it is obtained by suspending aluminum powder in trialkyl aluminum and adding hydrogen under high pressure. Therefore, in addition to trialkyl aluminum and dialkyl aluminum hydride, it usually contains 1 to several wt % of aluminum powder that has not reacted with the dialkyl aluminum hydride.

If the above mixture is used as it is for the reaction of halogenated germanes, the yield of germanes is extremely low. However, by adding alkyl aluminum halide to the above mixture and converting 90 moles or more of trialkylaluminium into dialkyl aluminum monohalide, the yield of germanes can be reduced. Although the yield is greatly improved, many by-products such as alkyl germane are generated.

The alkyl aluminum halide in the present invention is a compound represented by the general formula AIRnX, -.

X is a halogen, such as a chloro group or a bromine group.

R is an alkyl group having 1 to 10 carbon atoms, such as ethyl group, n-propyl group, or inbutyl group. However, since the presence of an alkyl group is not essential, n can be any number from 0, 1, and 1.5.

Among the compounds represented by the above general formula, preferred examples are ethylaluminum dichloride, ethylaluminum sesquichloride, inbutylaluminum dichloride, and aluminum chloride. The present invention can also be carried out by using a mixture of these compounds.

The type of alkylaluminium halide added to the mixture of alkyl aluminum hydride and trialkylaluminium may be different even if the alkyl groups are common.

Further, the dialkylaluminum monohalide referred to in the present invention is a compound represented by the general formula Aa or R2X.

``I*R2 is an alkyl group having 1 to 10 carbon atoms, such as an ethyl group, n-propyl group, or isobutyl group.They may be the same or different.

Or a halogen atom, such as chlorine or bromine.

Examples of the compounds represented by the above general formula include diethylaluminum monochloride and diisobutylaluminum monochloride.

Next, the amount of the alkyl aluminum halide specified in the present invention added to the mixture of the alkyl aluminum hydride and the trialkylaluminium is at least an amount sufficient to convert 90 mol% of the trialkylaluminium to dialkyl aluminum monohalide. . The amount added is determined by the amount of trialkylaluminum in the mixture and the amount of halogen atoms present in the alkyl aluminum halide. For example, in the case of an alkyl aluminum cybaride and an alkyl aluminum sesquihalide, it is necessary to add at least 90 mol % of the trialkylaluminum present in the mixture.

In the case of aluminum chloride, it must be added in an amount of 45 mol% or more.

In terms of examples, the alkyl aluminum ha according to the present invention R, A
7 +AJRX, → 2AJR,XR,Aj+A
JtR,X, -+ 3AJR,X2R, person t+A
ict, → 3AIR, CI, that is, an alkyl aluminum civalide and an alkyl aluminum sesquihalide react with an equivalent amount of trialkylaluminium to form a dialkyl aluminum monohalide,
Since aluminum chloride reacts with η equivalent of trialkylaluminium to produce dialkylaluminum monohalide, in the present invention these must be added in an amount of 90 mol % or more or 45 mol % or more, respectively.

The maximum amount of alkyl aluminum halide added is usually 2 moles. Exceeding this range is undesirable because the yield decreases.

What is important in the present invention is to use aluminum powder in an amount of 0.1 wt% or less relative to the dialkyl aluminum hydride, and in particular, by reducing the amount to 0.01 wt% or less, the amount of by-products such as alkylgermane can be significantly reduced. can be done.

There are no particular limitations on the method for removing aluminum powder, but it is also possible to separate aluminum powder as a residue by evaporating dialkyl aluminum hydride or trialkyl aluminum, or by filtration.

The hydrogenating agent in the present invention can be obtained by the method described above. As for the reaction method of this hydrogenating agent and the halogenated germane, the method disclosed in the above-mentioned Japanese Patent Application No. 59-073045 can be directly adopted, and it is also possible to use ethers to carry out the reaction at a lower temperature. The reaction temperature is -30 DEG to 100 DEG C. and usually 0 DEG to 50 DEG C. There is no particular restriction on the reaction pressure, and the reaction can be carried out at normal pressure.

Effects> By carrying out the method of the present invention, germanes can be produced using inexpensive dialkylaluminum without producing almost any by-products such as alkylgermanes, which is extremely valuable industrially.

<Example> The present invention will be further explained with reference to Examples below.

Example 1.2 and Comparative Example 1 A 500 ml stainless steel gas collection trap was connected to a SOOML stainless steel induction stirring autoclave with a gas flow meter interposed therebetween. Also, in the autoclave,
A metering pump for charging silicon tetrachloride dissolved in liquid paraffin from the outside was connected. The charging tube was a dip tube. These entire systems were placed in a helium atmosphere before the reaction. The gas collection trap was cooled with liquid nitrogen.

As a mixture of dialkyl aluminum hydride and trialkyl aluminum, a mixture containing 7Qwt% of diethylaluminum hydride and 30wt% of triethylaluminum was used. Comparative Example 1 contains aluminum powder at 1 Ovrt% based on diethyl aluminum hydride, and Example 1 contains aluminum powder in which aluminum powder is removed using a pressure filter pre-coated with diatomaceous earth (aluminum powder 0.008%).
%), in Example 2 simple distillation (15% under reduced pressure at 11% Hg)
0.0003% aluminum powder
The following was used.

These diethyl aluminum hydride and triethyl aluminum aV (aluminum powder mixture each had 49.2
II was diluted with 50 g of liquid paraffin.

In this case, 0.4 mol of diethylaluminum hydride and 0.129 mol of triethylaluminum were present. Add 16% of ethylaluminum dichloride to this mixture.
4 # (0,129 mol) was dissolved in 26 g of liquid paraffin and added dropwise. This amount is 100 molt, the amount required to convert triethylaluminum to diethyla/, L/miniram monochloride.

This mixture of six types of alkylaluminum compounds was placed in a container and degassed at 60° C. under a reduced pressure of 211 II Hg for 20 minutes. After that, the atmosphere was changed to helium and the distance was 500 m.
1 was charged into an autoclave.

21.4 g (0.1 mol) of germanium tetrachloride was dissolved in 281 g of liquid paraffin. Add this with a metering pump, 4
It was press-fitted into an autoclave kept at 0°C for 2 hours. The generated monogermane gas was collected in a trap.

After the reaction was completed, the remaining monogermane gas in the reaction system was sent to a trap and collected using helium.

The gas composition of the trap was measured by gas chromatography.

The results are shown in Table 1.

Claims (1)

[Claims] (1) Halogenated germanes are produced using a hydrogenating agent containing a sufficient amount of alkylaluminum halide to convert at least 90 mol% of trialkylaluminum into dialkylaluminum monohalide to a mixture of alkyl aluminum hydride and trialkylaluminium. 1. A method for producing germanes, characterized in that the hydrogenating agent contains metal aluminum in an amount of 0.1 wt % or less based on the alkyl aluminum hydride.