JPH09228088A - Pencil sharpener type electrolytic cell and production of organosilicon compound and organogermanium compound using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for keeping the space between a cathode and a sacrificial anode constant so that any short between the cathode and anode due to the build-up of deposits is not caused and any risk of catching fire of an organic solvent is eliminated at the time of producing an organosilicon compound and/or organogermanium compound with the electrolytuc cell using the sacrificial anode. SOLUTION: This electrolytic cell is provided with a sacrificial anode which is consumed by an electrochemical reaction in an organic electrolytic synthesis process. In the cell: an electrolytic cell main body that also functions as a cathode consists of a metallic vessel having a conical section whose apex angle is <45 deg.; pellets of the sacrificial anode metal are received in an electrically insulating cage-like container whose lower part has a comical shape having the same apex angle as that of the conical section of the metallic vessel; the cage-like container is suspended by using an anode fixing jig with which the upper section of the electrolytic cell is fitted; the anode fixing jig is provided with a mechanism for adjusting the space between the cathode and the sacrificial anode; and the metallic vessel is provided with an electrolytic solution inlet and an electrolytic solution outlet.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pencil sharpener type electrolytic cell using a sacrificial electrode, and a method for producing an organosilicon compound, an organogermanium compound or an organosilicon-germanium compound using the pencil sharpener type electrolytic cell.

[0002]

2. Description of the Related Art When synthesizing organic compounds such as carboxylic acids, alcohols, ketones and aldehydes by reducing organic halides and reacting with carbon dioxide and a proton source, a sacrificial anode placed in an electrolytic cell is used. A method has been proposed in which a fluidized electrolytic cell of a type in which the amount is sequentially lowered and is continuously replenished from the upper portion is used (see JP-A-62-56589). The electrolytic cell used here is a "pencil sharpener type electrolytic cell" in which a conical anode is brought into contact with a conical cathode frame through an insulating separator.
By using a mesh plastic as the separator, the reaction liquid is passed while ensuring the distance between the electrodes.

The present inventor has previously found that organic halosilane and / or
Alternatively, by electroreducing an organic halogermane using a sacrificial electrode, polysilane, polygermane, silane-germane copolymer and other organosilicon compounds and organogermanium compounds have been successfully produced (Japanese Patent Laid-Open No. 4-331235, JP-A-6-73180, JP-A-6-98077
No., etc.).

In the course of subsequent research, the present inventor has used the above sacrificial anode replenishment type electrolytic cell (in the present specification, simply "pencil sharpening type") in the production of the above-mentioned organosilicon compound. I have tried to use "electrolyzer"). However, in the production of organosilicon compounds and the like, metal halides produced as the reaction proceeds and metal particles produced by reduction at the cathode are deposited in the reaction solution and deposited on the separator portion to form a mesh. The phenomenon that the reaction solution was unable to circulate due to the blockage was observed. In addition, the conductive metal particles,
By attaching to the separator, the cathode and anode are short-circuited,
It was found that not only the electric potential required for the reaction cannot be secured, but also there is a problem in terms of safety such as a risk of ignition of the organic solvent due to spark generation.

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention provides a method for producing an organosilicon compound, an organogermanium compound, or an organosilicon-germanium compound by using a pencil sharpening type electrolytic cell using a sacrificial anode, and depositing accompanying the reaction. It is necessary to develop a new technology that can keep the distance between the cathode and the sacrificial anode constant so that there is no short circuit between the negative and anode due to the accumulation of substances and there is no risk of ignition of the organic solvent. The main purpose is.

[0006]

Means for Solving the Problems As a result of intensive studies in view of the state of the art as described above, the present inventor has found that a pencil sharpening type electrolytic cell using a sacrificial anode can be used especially for an organic silicon, an organic germanium compound or As a structure particularly suitable for producing an organosilicon-germanium compound, while being housed in an electrically insulating basket-like container suspended from the upper part of the electrolytic cell,
We have succeeded in solving or mitigating the problems of the prior art by developing an electrolytic cell in which a jig for fixing the anode is provided with a mechanism for adjusting the space between the negative and positive electrodes.

That is, the present invention provides a pencil-sharpening type electrolytic cell equipped with the following sacrificial anode, an organosilicon compound such as polysilane, an organogermanium compound such as polygermane, and an organosilicon-germanium such as silane-germane copolymer using the same. A method for producing a compound is provided.

[0008] 1. In a pencil sharpener type electrolytic cell provided with a sacrificial anode that is consumed by an electrochemical reaction during organic electrolytic synthesis, (a) an electrolytic cell body having a function as a cathode is
(B) Pellet-shaped sacrificial anode metal is composed of a metal container having a conical part with an apex angle of 45 ° or less, and the lower part has a conical shape with the same angle as the conical part of the metal container. It is housed in a container, (c) the basket-shaped container is hung by a jig for fixing the anode attached to the upper part of the electrolytic cell, and (d) the mechanism for adjusting the cathode-anode spacing is used for the jig for fixing the anode. The pencil sharpener type electrolytic cell is provided, and (e) the metal container is provided with an electrolytic solution inlet and an electrolytic solution outlet.

[0009] 2. A method for producing an organosilicon compound, an organogermanium compound or an organosilicon-germanium compound by subjecting an organic halosilane and / or an organic halogermane to electrode reduction using the pencil sharpening type electrolytic cell according to the above item 1.

3. The method according to item 2 above, wherein magnesium, aluminum, or an alloy thereof is used as the sacrificial anode.

4. Item 3. The method according to Item 2 above, wherein tetrahydrofuran (THF) or 1,2-dimethoxyethane is used as a solvent for dissolving the raw materials when carrying out the electrode reaction.

5. Item 3. The method according to Item 2 above, wherein lithium chloride or a lithium chloride-containing mixed salt is used as a supporting electrolyte when performing an electrode reaction.

6. Item 3. The method according to Item 2 above, wherein polysilane is produced using organic dichlorosilane and / or organic trichlorosilane as the organic halosilanes.

7. Uses magnesium, aluminum or their alloys as sacrificial anode and THF as solvent
3. The method according to item 2 above, wherein the polysilane is produced using lithium chloride or a mixed salt containing lithium chloride as a supporting electrolyte and organic dichlorosilane and / or organic trichlorosilane as organic halosilanes.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

An outline of a pencil sharpening type electrolytic cell according to the present invention is shown in FIG. 1 as a partially cutaway oblique view. However, in FIG.
The basket-like container for containing the pellet-shaped sacrificial anode is omitted. As shown in the figure, a metal container having a conical portion with an apex angle of 45 ° or less (more preferably about 15 to 20 °) in the lower portion and a flange portion joined to the conical portion in the upper portion is a electrolytic cell body And acts as a cathode.

The metal container as the main body of the electrolytic cell is provided with an anode fixing jig with a basket-like container for holding the pellet-shaped sacrificial anode in a predetermined position, and the anode fixing jig has an electrode that changes according to the consumption of the sacrificial anode. An inter-electrode distance adjustment unit for adjusting the inter-distance is provided.

The sacrificial anode used in the present invention is shown in FIG.
As shown in a perspective view, it is made of pellet-shaped metal housed in a cage-shaped anode container, and has a conical shape like a pencil with its tip shaved as a whole. The apex angle of the conical portion of the basket-shaped container for accommodating the pellet-shaped sacrificial anode is equal to that of the conical portion of the metal container and is 45 ° or less, more preferably 1
It is in the range of about 5 to 20 °. The pellet-shaped sacrificial electrode is stored in a basket-like container, and the anode fixing portion attached to the anode fixing jig shown in detail in FIG.
It is suspended inside a metal container and held in place.

The material of the basket-like container is not particularly limited as long as it is electrically insulative or insulative and has a strength capable of holding the pellet-shaped sacrificial electrode. Usually selected from stainless steel, copper, etc.
When using a conductive material as the material of the cage,
Needless to say, the surface of the surface is processed beforehand with insulation such as polytetrafluoroethylene. The thickness of the rod or wire forming the basket-like container may be determined in consideration of the size of the anode material pellets, the distance between the sacrificial anode and the metal container to be the cathode, and the like, but is not particularly limited. Usually, it is about 5 to 10 mm. The size of the opening of the cage is
It must be smaller than the anode material pellets it contains. If the aperture ratio is too small, the effective anode area facing the cathode becomes small and a sufficient amount of current cannot be secured. Therefore, it is desirable that the aperture ratio be as large as possible.
It is about 95%. The size of the pellet-shaped sacrificial anode is usually about 8 to 50 mm.

In the apparatus shown in the figure, the reaction solution enters the electrolytic cell through the reaction solution inlet at the tip of the conical portion of the metal container, and is subjected to electrode reaction between the sacrificial anode and the cathode (electrolytic cell or inner wall of the metal container). Meanwhile, it is sent upward and taken out of the system through the reaction solution outlet. Flow of the reaction liquid can be performed by any forced flow means such as a pump. The positions of the inlet and outlet of the reaction solution are not particularly limited, and they can be provided in an electrolytic cell or any other position, if necessary.

In the present invention, as shown in the figure, with the upper edge of the basket-shaped container for accommodating the pellet-shaped sacrificial anode supported by the anode container fixing portion shown in FIG. 3, the anode is placed at a predetermined position in the metal container. The electrode reaction is carried out. In order to efficiently carry out the electrode reaction according to the type of reaction raw material, it is necessary to maintain and adjust a predetermined interval between the conical portion of the basket-shaped container containing the pellet-shaped sacrificial anode and the conical cathode portion. Therefore, the jig for fixing the anode is provided with a mechanism for moving the cage-shaped container containing the sacrificial anode by the inter-electrode distance adjusting screw shown in FIG. 3 to adjust the distance between both electrodes. Although FIGS. 1 and 3 show an example in which the electrode reaction is carried out in a batch system, it goes without saying that the electrode reaction can be carried out continuously in the present invention.

In the present invention, when the synthesis reaction of polysilanes, polygermanes or silane-germane copolymers is carried out, the material of the pellet-shaped sacrificial anode is Mg,
Al or alloys containing these metals as main components (Mg-A
1 alloy, Mg-Al-Zn alloy, etc.) are suitable.

The material of the cathode (electrolytic cell or inner wall of the metal container) is not particularly limited as long as it is a substance capable of passing an electric current, and specifically, stainless steel such as SUS304 and SUS316,
Examples include Mg, Cu, Zn, Sn, Al, Ni, Co, and carbon materials.

The material of the anode fixing jig is not particularly limited as long as it has a strength capable of supporting the weight of the anode, and concrete examples thereof include stainless steel such as SUS304 and SUS316. It is preferable that the surface of the anode fixing jig, the inter-electrode distance adjusting portion, etc. be covered with a fluororesin such as polytetrafluoroethylene to be insulated.

The distance between the cathode and the sacrificial anode is usually 5 to 30 mm.
The distance is more preferably about 7 to 15 mm, and as described above, it can be set within an error of 0.3 mm by the inter-electrode distance adjusting screw. In the production of polysilane,
If the distance between the cathode and the sacrificial anode is too small, the metal halide and the metal particles that are formed block the cathode and the anode, resulting in a short circuit. On the other hand, when the distance between both electrodes is too large, the distance between the solutions through which the current flows becomes large, so that the solution resistance becomes large and a large amount of Joule heat is generated, resulting in a decrease in energy efficiency.

Representative materials which can be subjected to the electrode reduction reaction in the present invention are halosilane and halogermane shown in Table 1. Materials produced by the electrode reduction reaction according to the present invention include disilanes and polysilanes having Si-Si bonds shown in Table 1, and Ge-G.
It is a material having various structures and compositions by arbitrarily combining raw materials 1 to 6, including digermane and polygermane having an e-bond.

[0027]

[Table 1]

In Table 1, R is a hydrogen atom and an organic substituent such as an alkyl group, an aryl group and an alkoxy group, and a plurality of Rs may be different from each other, or two or more of them are different from each other. It may be the same. More specifically, when the organic substituent is an alkyl group, it has 1 to 10 carbon atoms.
The thing of about 1 to 6 is mentioned among these, and the thing of C1-C6 is more preferable among these. Examples of the aryl group include a phenyl group, a phenyl group having at least one alkyl group having 1 to 6 carbon atoms as a substituent, a p-alkoxyphenyl group, and the like. Alkoxy group has 1 carbon
There are about 10 to 10 carbon atoms, and among them, carbon number 1
More preferably, it is from 6 to 6.

Further, in Table 1, X represents a halogen atom (Cl, F, Br, I). 2 or more X in raw material
, Each may be different, or 2
One or more may be the same. C as a halogen atom
l is more preferred.

In the method of the present invention, the halosilane and halogermane are preferably as pure as possible, for example, they are preferably distilled before use.

In the reaction, halosilane or / and halogermane are dissolved in a solvent before use. As the solvent, aprotic solvents can be widely used, and more specifically, propylene carbonate, acetonitrile, dimethylformamide, dimethylsulfoxide, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether,
Examples of the solvent include p-dioxane, tetrahydrofuran and methylene chloride. These solvents can be used alone or as a mixture of two or more. As the solvent, tetrahydrofuran and 1,2-dimethoxyethane are more preferable, and tetrahydrofuran is further preferable.

If the concentration of halosilane and / or halogermane in the reaction solution is too low, the current efficiency will decrease, whereas if it is too high, the supporting electrolyte may not dissolve. Therefore, the concentration of halosilane and halogermane in the solution is usually about 0.05 to 3 mol / l, more preferably about 0.1 to 1.5 mol / l, and particularly preferably about 0.4 to 0.7 mol / l. When the halosilane and halogermane are used in combination, the total concentration should be within these ranges.

Examples of the supporting electrolyte used in the present invention include alkali metal salts of perchloric acid such as sodium perchlorate and lithium perchlorate: tetraalkylammonium perchlorate such as tetra-n-butylammonium perchlorate: and Examples include lithium chloride. When lithium chloride is used as the supporting electrolyte, Fe, Al, Mg, Z
It is preferable to add chloride salts such as n, Sn, Co, Pd, V and Cu as an energization aid, and among these chloride salts, chloride salts of Fe, Al and Co are preferable. The above supporting electrolytes may be used alone or in combination of two or more kinds.

If the concentration of the supporting electrolyte is too low,
The reaction does not proceed sufficiently because the ionic conductivity given to the reaction solution is low, whereas when it is too high, the current flows too much and the potential required for the reaction cannot be obtained. Therefore, the concentration of the supporting electrolyte in the solvent is usually 0.05-5 m.
It is about ol / l, more preferably about 0.1 to 3 mol / l, and particularly preferably about 0.2 to 1 mol / l. The concentration of the energization aid when using lithium chloride as a supporting electrolyte is usually about 0.01 to 2 mol / l, more preferably about 0.01 to 0.6 mol / l, and particularly preferably 0.02 to 0.
It is 3 mol / l.

The amount of electricity applied is usually 1 F / mol or more, preferably 1.25 to 1.75 F / mol, based on the halogen atom in halosilane and / or halogermane. In addition, when synthesizing a polymer material such as polysilane, the molecular weight can be controlled by adjusting the amount of electric current. The reaction time varies depending on the amount of the raw material halosilane and / or halogermane, the resistance of the electrolytic solution related to the amount of the supporting electrolyte, the molecular weight of the desired polymer material, etc.
It may be determined as needed.

The current density is usually based on the cathode area.
It is about 0.5 to 10 A / dm ² , and more preferably about 1 to 5 A / dm ² .

The reaction temperature can be used as long as it is not higher than the boiling point of the solvent used, but if it becomes 5 ° C. or lower, the metal halide formed with the reaction is accumulated in equipment such as a heat exchanger constituting the reaction apparatus. Therefore, more preferably 5 to 2
5 ° C.

If the flow rate of the reaction solution in the electrolytic cell is too slow, an insulating metal halide adheres to the surface of the cathode and causes a blockage between the cathode and the anode. It is desirable to set it to 10 cm / sec or more.

In carrying out the method according to the present invention, a pencil sharpener type electrolytic cell, a reaction solution storage tank, a pump, a heat exchanger,
In the electrode reactor in which the strainer and the pipe for removing the metal halide are welded or joined with a flange, put the solvent, the supporting electrolyte, the current-carrying aid, and the raw materials, and while circulating the reaction solution with a pump, The electrode reaction is performed by applying a fixed amount of current. The inside of the electrode reactor is preferably replaced with dry nitrogen or an inert gas in advance.

[0040]

According to the present invention, the following remarkable effects are achieved.

(A) An organic silicon compound such as polysilane and an organic germanium compound can be efficiently synthesized by using a pencil sharpening type electrolytic cell using a sacrificial anode.

(B) The pellet-shaped sacrificial anode housed in the basket-like container is fixed on the upper part of the electrolytic cell and hung so that an insert such as a separator is not placed between the sacrificial anode and the cathode. A constant distance between the cathode and the anode can be maintained, and the reaction solution can be smoothly circulated.

(C) Since the metal halide and the metal fine particles produced with the progress of the reaction are no longer deposited between the negative and positive electrodes, the negative and positive electrodes are not blocked or short-circuited.
The reaction can be carried out smoothly.

(D) The risk of a fire due to an electric spark caused by a short circuit between the negative and positive electrodes is greatly reduced, and the reaction can be safely performed even when a large current is passed.

(E) In particular, magnesium, aluminum or their alloys are used as the sacrificial anode, THF is used as the solvent, lithium chloride or a mixed salt containing lithium chloride is used as the supporting electrolyte, and organic dihalogenates are used as the organic halosilanes. When using chlorosilane and / or organic trichlorosilane, polysilane can be produced in high yield.

[0046]

EXAMPLES Examples are shown below to further clarify the features of the present invention.

Example 1 The present invention was carried out using the pencil sharpener type electrolytic cell shown in FIG. That is, it consists of a cone part (height 585 mm x diameter 220 mm; apex angle 18 °) and a column part (diameter 220 mm x height 450 mm), and the surface is insulated with polytetrafluoroethylene.
Pelletized Mg (particle size 15 to 50 mm) is housed in a SUS304 basket-like container (steel wire forming the basket = 2 mm, opening size = 15 mm x 15 mm, opening ratio = 86%). Suspend in the electrolytic cell (the apex of the cone is the same as the apex of the cage containing the Mg anode) by the jig for fixing the anode so that the distance between the cathode and cage in the cone is 8 mm. Held down.

A pencil-sharpening type electrolytic cell having a SUS304 container as a cathode (also serving as the outer wall of the electrolytic cell) (in which the pellet-shaped Mg anode is installed) and a reaction liquid storage tank having a capacity of 20 liters (not shown) No.), canned circulation pump (not shown), heat exchanger (not shown), pipes (not shown), etc. are introduced into the circulation electrode reactor as nitrogen gas for about 3 hours. After replacing the atmosphere with nitrogen, 910 g of anhydrous lithium chloride (LiCl) and anhydrous ferrous chloride (FeC
l ₂ ) 549 g and THF 35 liters were added. After dissolving LiCl and FeCl ₂ with a stirrer installed in the reaction solution storage tank, add 3.35 kg of raw material methylphenyldichlorosilane and circulate the reaction solution with a circulation pump (when passing the intermediate point between the electrodes. The linear velocity was 36.0 cm / sec), and the reaction temperature was kept at 15 ° C, while constant current electrolysis was performed at a current value of 50.4 A. The energization was performed for about 23.2 hours so that the energization amount was 2.5 F / mol based on the raw material. The voltage value required immediately after the start of electrolysis was 163 V and the voltage at the end of electrolysis was 75 V, and the energization could be completed without short-circuiting the cathode and anode.

After completion of the reaction, the reaction solution was washed by a conventional method, extracted and reprecipitated to obtain 910 g of methylphenylpolysilane. When the molecular weight distribution of the obtained polysilane was examined by liquid chromatography, the weight average molecular weight was 15620.

The amount of consumption of the pellet-shaped sacrificial anode after the reaction was 650 g.

Example 2 The reaction was performed in the same manner as in Example 1 except that the current value was 75.6A. At this time, the voltage required immediately after the start of electrolysis was 245V, and the voltage at the end of electrolysis was 93V. As a result, 896 g of methylphenylpolysilane having a weight average molecular weight of 15550 was obtained.

Example 3 The reaction was carried out in the same manner as in Example 1 except that the raw material concentration was 0.63 mol / l. At this time, the voltage value required immediately after the start of electrolysis was 239.
V, the voltage at the end of electrolysis was 90V. As a result, 1190 g of methylphenylpolysilane having a weight average molecular weight of 18570 was obtained.

Example 4 The reaction was performed in the same manner as in Example 1 except that the distance between the electrodes was 10 mm. At this time, the voltage value required immediately after the start of electrolysis was 188V,
The voltage at the end of electrolysis was 89V. As a result, 870 g of methylphenylpolysilane having a weight average molecular weight of 12690 was obtained.

Example 5 A reaction was performed in the same manner as in Example 1 except that Al was used as the anode and diphenyldichlorosilane was used as the raw material.
At this time, the voltage value required immediately after the start of electrolysis was 27V, and the voltage at the end of electrolysis was 13V. As a result, the weight average molecular weight 297
2390 g of 0 diphenylpolysilane was obtained.

Example 6 A reaction was carried out in the same manner as in Example 1 except that phenylbutyl kudilogermane was used as a raw material. At this time, the voltage required immediately after the start of electrolysis was 93V and the voltage at the end of electrolysis was 40V.
Met. As a result, 679 g of phenyldibutyl polygermane having a weight average molecular weight of 23,600 was obtained.

Example 7 A reaction was carried out in the same manner as in Example 1 except that dimethylphenylchlorosilane was used as a raw material. At this time, the voltage required immediately after the start of electrolysis was 138V, and the voltage at the end of electrolysis was 38V. After completion of the reaction, the product was washed, extracted, distilled (bp. 89-92 ° C, 3 mmHg) according to a conventional method and purified to obtain 1150 g of the corresponding disilane.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an outline of a pencil sharpener type electrolytic cell according to the present invention.

FIG. 2 is a perspective view showing a sacrificial anode used in the present invention.

FIG. 3 is a perspective view showing a jig for fixing an anode used in the present invention.

Claims (7)

[Claims] 1. In a pencil sharpening type electrolytic cell provided with a sacrificial anode that is consumed by an electrochemical reaction during organic electrolytic synthesis, (a) an electrolytic cell body having a function as a cathode has an apex angle of 45 ° or less. The sacrificial anode metal in the form of a pellet is contained in an electrically insulating cage-like container having a conical shape whose lower portion has the same angle as the conical portion of the metal container. , (C) the basket-like container is suspended by an anode fixing jig attached to the upper part of the electrolytic cell, and (d) a mechanism for adjusting the cathode-anode spacing is provided in the anode fixing jig. e) A pencil sharpener type electrolytic cell characterized in that a metal container is provided with an electrolytic solution inlet and an electrolytic solution outlet. 2. An organosilicon compound, an organogermanium compound or an organosilicon-germanium compound is obtained by subjecting an organic halosilane and / or an organic halogermane to electrode reduction using the pencil sharpening type electrolytic cell according to claim 1. Method of manufacturing. 3. The method according to claim 2, wherein magnesium, aluminum or an alloy thereof is used as the sacrificial anode. 4. The method according to claim 2, wherein tetrahydrofuran (THF) or 1,2-dimethoxyethane is used as a solvent for dissolving the raw material when carrying out the electrode reaction. 5. The method according to claim 2, wherein lithium chloride or a mixed salt containing lithium chloride is used as a supporting electrolyte for carrying out an electrode reaction. 6. The method according to claim 2, wherein polysilane is produced by using organic dichlorosilane and / or organic trichlorosilane as the organic halosilane. 7. Magnesium, aluminum or an alloy thereof is used as a sacrificial anode, THF is used as a solvent, lithium chloride or a mixed salt containing lithium chloride is used as a supporting electrolyte, and organic dichlorosilane and / or organic halosilanes are used. The method according to claim 2, wherein the polysilane is produced using an organic trichlorosilane.