JPH0296584A - Production method of high purity quaternary phosphonium hydroxide - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a high purity quaternary phosphonium hydroxide and a method for producing the same. Furthermore, polymerization catalysts useful in the production of polysiloxanes (UK Patent No. 794,119) and intermediate raw materials used in the production of quaternary phosphonium salts for electrolytes in electrolytic capacitors (JP-A-62-272-51)
2, Japanese Patent Application Laid-open No. 62-272,513), and furthermore, curing of epoxy resin with excellent electrical properties, which is widely used for sealing and impregnating electronic components such as semiconductor devices and electronic devices. The present invention relates to high-purity quaternary phosphonium hydroxide, which is an intermediate raw material for high-purity quaternary phosphonium salts useful in catalysts, etc., and a method for producing it by electrolysis.

[Prior Art] and [Problem to be Solved by the Invention] Conventionally, as a method for producing quaternary phosphonium hydroxide, tetra-n-butylphosphonium iodide is reacted with silver oxide in an aqueous solution to produce quaternary phosphonium hydroxide. A method for obtaining phosphonium hydroxide (UK Patent No. 794,119) is known. The reaction formula is shown below.

(n-C4119)4P14-1/2AgO÷1/21
120 → (n-C411s)4POII+Agl However, since silver oxide is expensive, this method increases the production cost and is not an industrially desirable method.

On the other hand, co-authored by G.M. Kozolahoff and El Meyer, “
Organic Phosphorous Compound” Willy
Published by Interscience (G, M, KO30LAP)
OFF and L, MAIERr 0RGANIC
pHO5PIIOnUSGOMPOUUNDJ WILE
Y-INTER5CIENCE, a Divisio
nof John Wiley & 5ons, Inc.
) Vol. 2, p. 201.

(1972) describes that quaternary phosphonium salts can be ion-exchanged using an ion-exchange resin.

However, as described in the same book, when performing ion exchange using an ion exchange resin, it is generally necessary to dilute the concentration of the stock solution, which has the disadvantage of requiring a long time for ion exchange.

In addition, in order to overcome this point, Japanese Patent Application Laid-Open No. 62-212,397
The publication describes a method for obtaining quaternary phosphonium hydroxide by contacting a quaternary phosphonium halide with a strongly basic anion exchange resin (type 011) in a relatively high concentration region and ion-exchanging it. Yes. However,
In the case of this method, as described in the examples, ion exchange is not completed (yield: 66.4-9.
0.8%), it is unavoidable that the raw material quaternary phosphonium halide is mixed into the effluent, and inadvertently, the quaternary phosphonium halide is mixed using an organic solvent such as a halogenated hydrocarbon. A process is required to remove the

Furthermore, even if the raw material quaternary phosphonium pallite is removed using a solvent, it is difficult to completely recover it from the effluent, and analysis of the amount of herogen in the effluent reveals a range of numbers ranging from several hundred to several hundred. 10[]Oppm is included.

As mentioned above, all of the conventional methods either fail to provide highly pure quaternary phosphonium hydroxide or are not suitable for industrial use at all.

As a result of intensive and detailed research in view of the above-mentioned problems, the present inventors electrolyzed a quaternary phosphonium salt aqueous solution in an electrolytic cell comprising an anion exchange membrane and a cation exchange 1 model as a diaphragm. The present invention was completed based on the discovery that it is possible to produce quaternary phosphonium hydroxide with unexpectedly high yield and high purity.

[Means for Solving the Problems] That is, 1 the present invention has the following general formula [I] (wherein R,
, R2, R, and 1 are substituted with an alkyl group, an aryl group, an aralkyl group, or at least one group thereof having 1 to 8 carbon atoms, or a hydroxyl group or an alkoxyl group) The present invention relates to a high-purity quaternary phosphonium hydroxide, which is an aqueous solution of quaternary phosphonium hydroxide, characterized in that each metal ion or anion in the aqueous solution is present at 1 ppm or less.

Further, the present invention provides an electrolytic cell having a four-cell structure partitioned by one anion exchange membrane and two cation exchange membranes sandwiching it, which has the following general formula [II] (where R, , R2, R, and has 1 to 8 carbon atoms
represents an alkyl group, an aryl group, an aralkyl group, or one in which at least one group thereof is substituted with a hydroxyl group or an alkoxyl group, and xo represents an anion) An aqueous solution of a quaternary phosphonium salt represented by The present invention relates to a method for producing high-purity quaternary phosphonium hydroxide, which is characterized by obtaining quaternary phosphonium hydroxide from a cathode chamber.

The present invention will be explained in detail below.

The high purity quaternary phosphonium hydroxide of the present invention is
A high-purity quaternary phosphonium hydroxide aqueous solution represented by the general formula [I] is provided, and each metal ion or anion contained in the aqueous solution is 1 p.
It is characterized by being below pm.

In the general formula [I], R1, R2, R3 and R
4 represents an alkyl group having 1 to 8 carbon atoms, an aryl group, an aralkyl group, or at least one group thereof substituted with a hydroxyl group or an alkoxyl group. To give specific examples, examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, and octyl, examples of the aryl group include phenyl, tolyl, and xylyl, and examples of the aralkyl group include benzyl. , phenityl, etc.
Also included are those in which at least one of the above groups is substituted with a hydroxyl group or an alkoxyl group. Further, R1 to R4 may be of the same type or different types.

Further, the concentration of the high purity quaternary phosphonium hydroxide aqueous solution is usually 2 to 50 wL%, preferably 3 to 30%.
A range of wt% is desirable. The reason for this is that low concentrations are not economical, and if the concentration exceeds 50% by weight, the quaternary phosphonium hydroxide tends to decompose, which is not preferable.

Furthermore, the aqueous solution of high-purity quaternary phosphonium hydroxide of the present invention contains very few metal ions or anions as impurities, and the content thereof is 1 ppm or less. Such high purity can be achieved. Further, examples of metal ions or anions contained in the aqueous solution include Na and K.

Fe, Ni, Cr, Cu, Ba,
Pb, Ti, Zn, Aj+, Cj),
Br.

1, SO, and a counter anion constituting a quaternary phosphonium salt. However, since these are in trace amounts, the high-purity quaternary phosphonium hydroxide of the present invention is a high-purity quaternary phosphonium salt useful as a polymerization catalyst, a Tft electrolytic capacitor electrolyte, an epoxy resin curing catalyst, etc. It is suitable as an intermediate raw material.

Next, a method for producing high purity quaternary phosphonium hydroxide of the present invention will be explained.

The specific method is to partition the electrolytic cell with one anion exchange membrane and two cation exchange membranes sandwiching it, forming a four-cell structure consisting of an anode chamber, an rA electrode chamber, and two intermediate chambers, An acidic electrolyte solution is supplied to the anode chamber, water is supplied to the cathode chamber and anode side intermediate chamber (Nakae Denko), and a quaternary phosphonium salt aqueous solution is supplied to the cathode side intermediate chamber (intermediate chamber ■), and a direct current is generated between the two electrodes. This is a method for obtaining highly pure quaternary phosphonium hydroxide from the cathode chamber by applying an electric current.

In the present invention, a normal cation exchange membrane can be used as the cation exchange membrane, for example, Selemion ■C
Examples include MV (manufactured by Asahi Glass Co., Ltd.), Neo Sebuta CM-1 (manufactured by Tokuyama Kotatsu), and Nafion 324 (manufactured by DuPont).

Further, as the anion exchange membrane, a normal anion exchange membrane can be used, such as Selemion AMV (
Asahi Glass ■), Neo Sebuta ■ AM-1 (Tokuyama Teitatsu ■)
etc.

In addition, as for the material constituting the electrode, it is preferable for the anode to be a stable material that is resistant to halogen, oxygen, etc. generated by electrolysis of a quaternary phosphonium salt, such as graphite,
It is preferable to use electrodes made of lead, alloys thereof, various metals coated with white metal, or the like. Furthermore, it is preferable to use an alkali-resistant material for the eyelids, such as stainless steel or nickel.

As for the materials constituting the electrolytic cell, synthetic resins such as fluororesin, polypropylene, polyethylene, etc. are used for the anode chamber and the intermediate chamber, and the synthetic resin used for the anode chamber, and alkali-resistant stainless steel, etc. are used for the cathode chamber. However, it can be used enough.

In the present invention, the quaternary phosphonium salt supplied to the cathode side intermediate chamber (intermediate chamber II) has the following general formula [II
] (In the formula, R, , R2, R3 and R4 mean the same as the above. Xo represents an anion).

In the general formula [11], RI to R4 represent the same as described above. Xo represents an anion (acid group), such as fluorine, J1! Halogen ions such as chlorine, bromine, and iodine; organic carboxyl ions such as formic acid, acetic acid, and oxalic acid;
Examples include sulfuric acid, dimethyl and diethyl sulfate ions, nitrate ions, phosphate ions, methyl and dimethyl phosphate ions, organic phosphate ions such as ethyl and diethyl phosphate, and hydroxyl groups (OH-). It is not limited to anions.

When electrolyzing the quaternary phosphonium salt aqueous solution of the present invention, a DC voltage is applied, or the current density at that time is usually 1.
~50A/da2. Preferably 2 to 30 A/dm2. The temperature of the electrolyte is sufficient at room temperature, but in order to prevent corrosion of the anode and decomposition of the target substance in the catholyte,
It is preferable to keep it below o”c.

The method for supplying the quaternary phosphonium salt aqueous solution to the electrolytic cell is as follows:
It can be carried out in any of the circulation type, continuous type, and semi-continuous type. This quaternary phosphonium salt aqueous solution is supplied to the cathode side intermediate chamber (intermediate chamber II), and the concentration at that time depends on the type of quaternary phosphonium salt and the high purity quaternary phosphonium of the target product produced in the cathode chamber. Although it varies depending on the quality of the hydroxide, it is usually set at 2 to 50 wt%, preferably 3 to 30 wt%. The reason for this is that when a high concentration of quaternary phosphonium salt exceeding 50w% is supplied to the intermediate chamber on the cathode side (intermediate chamber II), anions (acid groups) will diffuse back to the cathode chamber to some extent through the cation exchange membrane. . in this case,
The concentration in the intermediate chamber on the cathode side (intermediate chamber ■) is set to 2 to 50% as described above.
By keeping 7JG within the range of wL%, it is possible to suppress back diffusion of anions to the cathode chamber. Furthermore, in the case of anion or hydroxyl group, that is, when purifying crude quaternary phosphonium hydroxide, the method according to the present invention can be applied, and in this case, there is no need to particularly limit the concentration.
In general, quaternary phosphonium hydroxide has poor stability and decomposes into the corresponding phosphine oxide at high concentrations, so it is not preferable to use it at extremely high concentrations of 50 wt% or more.

In addition, in the present invention, especially if the quaternary phosphonium salt aqueous solution contains halogen ions or nitrate ions as a main component or as impurities, they will be harmful and highly corrosive if they reach the anode during electrolysis. Gases such as chemical halogens and nitrogen oxides are generated in high concentrations, corrode the anode itself, and the corrosion products migrate to the catholyte, reducing the purity of the target product, quaternary phosphonium hydroxide. In addition to inviting a synthetic resin anode chamber and cation exchange membrane.

It causes deterioration of the anion exchange membrane. Therefore, corrosive anions, typically halogen ions, from the quaternary phosphonium salt aqueous solution supplied to the cathode-side intermediate chamber (intermediate chamber ■) are transferred from the cathode-side intermediate chamber (intermediate chamber ■) to the anode side during electrolysis. In order to prevent the transition from passing through the intermediate chamber (intermediate chamber I) to the anode chamber, an anion exchange membrane was used as a partition between the cathode side intermediate chamber (intermediate chamber ■) and the anode side intermediate chamber (Zakae Electric Works). ,
The important significance of this method lies in the dual use of a cation exchange membrane as a diaphragm between the anode side intermediate chamber (Nakae Electric Works) and the anode chamber.

That is, by using an anion exchange membrane and a cation exchange membrane as a partition between the anode chamber and the cathode side intermediate chamber (intermediate chamber ■), the anode, anode chamber, cation exchange membrane, and anion exchange membrane are separated during electrolysis. It is possible to suppress the generation of corrosive gases that cause deterioration.

On the other hand, due to the presence of a cation exchange membrane that is a partition between the cathode chamber and the cathode side intermediate chamber (intermediate chamber ■), only the desired quaternary phosphonium cations are transferred from the cathode side intermediate chamber (intermediate chamber ■) to the cathode chamber. High purity quaternary phosphonium hydroxide can be obtained in the transferred cathode chamber.

Next, the acidic electrolyte used in the solution supplied to the anode chamber should be one that causes less corrosion or deterioration of the material constituting the anode chamber and does not generate corrosive or toxic gases. Examples include dilute aqueous solutions such as sulfuric acid and phosphoric acid, and aqueous solutions of organic acids such as formic acid, oxalic acid and tartaric acid. These acidic electrolytes do not need to be used in high concentrations and have a conductivity required for electrolysis, such as 5 to 300 m5, preferably 10 to
200! It is sufficient to have a concentration of Is. Expressing these concentrations in concrete numbers, for sulfuric acid it is 1.0
~IO, Owt%, and for oxalic acid it is 2.0 to 10wt%.

On the other hand, pure water is supplied to the cathode chamber and the intermediate chamber on the anode side (intermediate chamber ■), but at the beginning of operation, pure water is difficult to cause electrolysis, so the target product is quaternary phosphonium as an electrolyte. A small amount of hydroxide, for example 0.01 to 10.
It is preferable to add about Owt%.

In addition, the method of supplying each aqueous solution to the anode chamber, the anode side intermediate chamber (Nakae Electric Works), the cathode side intermediate chamber (intermediate chamber ■), and the cathode chamber can be carried out by a circulation type, a continuous type, or a semi-continuous type. I can do it. The residence time of each aqueous solution in each chamber is 1~
It is carried out for 60 seconds, preferably 1 to 10 seconds.

As the electrolysis progresses, the concentration of high-purity quaternary phosphonium hydroxide, the target product, in the cathode chamber solution increases, but in consideration of the stability of quaternary phosphonium hydroxide, the concentration is lower than 50 wt%. When the desired concentration is reached, it is diluted with wood and collected continuously or in pouches.

The quaternary phosphonium salt supplied to the intermediate chamber on the cathode side (intermediate chamber ■) is consumed and its concentration decreases, but it is sufficient to supplement the quaternary phosphonium salt as needed.

In addition, in the anode side intermediate chamber (Nakae Denko), the concentration of the counter anion of the quaternary phosphonium salt increases or is diluted with water and is continuously or hatchwise recovered from the system.

Thus, it became possible to continuously and efficiently produce quaternary phosphonium hydroxide from quaternary phosphonium salt.

It goes without saying that before starting electrolysis, the electrodes, electrolytic cell, and other systems should be thoroughly washed with pure water to prevent any impurities from entering.

[Function] The method for producing high-purity quaternary phosphonium hydroxide of the present invention involves supplying an acidic electrolyte solution to an anode chamber divided by a cation exchange IV2 and water to a cathode chamber, and also supplying an anion exchange membrane and an anion exchange membrane. Anode side intermediate chamber divided by cation exchange membrane (
An anion exchange membrane with a selective permeation effect is produced by supplying water to the intermediate chamber (intermediate chamber II) on the cathode side and a quaternary phosphonium salt aqueous solution to the intermediate chamber (intermediate chamber II) on the cathode side, and passing a direct current between the two electrodes. In the anode chamber, which is divided by two cation exchange membranes, the e-condensation of halogen ions contained as the main component or impurity of the quaternary phosphonium salt, the generation of gases such as nitrogen oxides, etc. Since no diffusion occurs and only the quaternary phosphonium cations in the cathode chamber selectively permeate through the cation exchange membrane from the anode to the cathode, it is possible to obtain highly pure quaternary phosphonium hydroxide.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Two cation exchange membranes Nafion 3
24 (manufactured by DuPont, fluororesin-based cation exchange membrane) and one anion exchange membrane AMV (manufactured by Asahi Glass, Bostyrene-based anion exchange membrane) between them. Intermediate electrician (anode side intermediate chamber), intermediate chamber II (
It was divided into four chambers: an intermediate chamber on the cathode side) and a cathode chamber.

A titanium plate coated with platinum was used as the anode, and a stainless steel (SO3304) plate was used as the cathode, and all four chambers were thoroughly washed with pure water in advance.

Then, in the anode chamber, 2.9:I wL% Shu m4.2
8 kg of 2.51 wt% hydrobromic acid 1 in intermediate chamber I.
2.5 kg, 6 kg of 7.61 wL% tetraethylphosphonium puromite IJ in the intermediate chamber (■), and 2.5 kg in the cathode chamber. 11.6 kg of an aqueous solution of tetraethylphosphonium hydroxide with a concentration of
Electrolysis was carried out for 6 hours. As a result, 8.
12.04 kg of a 68 wt % aqueous solution of tetraethylphosphonium hydroxide was obtained. The amount of current at this time is 81
The current efficiency was 59.4% at 3F.

As a result of analyzing the impurities in the tetraethylphosphonium hydroxide aqueous solution obtained in the cathode chamber, it was found that Na≦0. O5
ppm, K≦0.01ppm, Fe≦0.01p
pm, Ni≦0, O2ppm, Cr≦0.01
ppIl, Cu≦0. O2ppm, Ba≦0.
02 ppm, Pb≦0.051)l)01.
Ti≦0.01ppm, CI! ≦0.2ppm, B
The purity was extremely high with r≦0.21)l and SO4≦0.2ppm.

Example 2 Using the same equipment as in Example 1, 1. Owt% sulfuric acid 4, 12 kg, 0.90 wt% hydrobromic acid 14.9 kg in intermediate chamber I, 10.0 wt% in intermediate chamber H. 16.6 kg of Owt% tetraethylphosphonium puromite and 3.92 kg of an aqueous solution of 0.66 L% tetraethylphosphonium hydroxide were supplied to the cathode chamber, and 20 to 22 V was applied between the anode and cathode at room temperature. Electrolysis was carried out for 37 hours by applying a DC voltage of . As a result, 4.27 kg of a 10.5 wt% tetraethylphosphonium hydroxide aqueous solution was placed in the cathode chamber (11). The amount of current applied at this time was 4.5F, and the current efficiency was 57%.

As a result of analyzing the impurities in the obtained tetraethylphosphonium hydroxide aqueous solution, Na=0. O7pp
m, K≦0.01ppm, Fe=0.0:
lppm, Ni≦0.01ppm.

Cr≦0.01ppm, Cu≦0. O2ppm,
Ba=0.004 ppm.

Ti≦0.01pp＋＊, CI! ≦0.2ppm
, Br≦0-2I)l)l, 504=0.4
The purity was extremely high at 5pp+*.

Example 3 Using the same equipment as in Example 1, 4.6 wt% was added to the anode chamber.
4.02 kg of oxalic acid aqueous solution, 3.24 kg to Chubu Electric Works
15.0 kg of vt% hydroiodic acid, 9.8 in the middle chamber ■
wt% triethylmethylphosphonium iodite 9
．． 5 kg, and a 0.35 wt% aqueous solution of triethylmethylphosphonium hydroxide in the cathode chamber: 1.
99kg was supplied, and 20~20~
Electrolysis was carried out for 25 hours by applying a DC voltage of 22V. As a result, 4.65 kg of a 9.3 wt % triethylmethylphosphonium hydroxide aqueous solution was obtained in the cathode chamber.

At this time, the current flow rate was 3.90F and the current efficiency was 71.5%.
Met.

As a result of analyzing the impurities in the obtained triethylmethylphosphonium hydroxide aqueous solution, Na≦0, O5pp
m, K≦0.01ppm, Fe=0.01ppm
m, Ni≦0.01ppH1, Cr≦0.01pp
m, Cu≦0. O2ppm, Ba≦0. O2p
pm, Pb≦O, O5ppm, Ti≦0. [l
lppm, CI! ≦0. lppm, nr≦0. l
ppm, l≦0il) pH, SO, ≦0.2ppm
It was extremely pure.

Example 4 Using Example 1 and a rotating device, 4.5 wt% was added to the anode chamber.
4.5 kg of oxalic acid aqueous solution, 1.0 w in intermediate chamber I
L% hydrobromic acid4. :1kg, 8.5 in intermediate chamber H
wt, % tetraethylphosphonium hydroxide 1
7.8 kg.

In addition, there are 2. :l wt% tetraethylphosphonium hydroxide aqueous solution (4.5 kg) was supplied, and a DC voltage of 20 to 22 V was applied between the anode and the cathode at room temperature to perform electrolysis for 24 hours. As a result, 4.95 kg of a 11.8 wL% tetraethylphosphonium hydroxide aqueous solution was obtained in the cathode chamber. At this time, energization 4 is 4
．． At 48F, the current efficiency was 65.4%.

The results of analyzing impurities in the tetraethylphosphonium hydroxide aqueous solution before and after electrolysis are shown in Table 1 below.
It was as follows.

[Effects of the Invention] As explained above, the high-purity quaternary phosphonium hydroxide of the present invention has high purity, so it can be used as a polymerization catalyst, an intermediate raw material used in the production of a quaternary phosphonium salt for electrolyte of an electrolytic capacitor, and a semiconductor device. It is useful as a raw material for curing catalysts for epoxy resins with excellent electrical properties, which are widely used for sealing and impregnating electronic parts and devices such as epoxy resins.

In addition, the high purity quaternary phosphonium hydroxide of the present invention has a four-tank structure divided by one anion exchange membrane and two cation exchange membranes sandwiching it.
By subjecting an aqueous J4 phosphonium salt solution to direct current electrolysis, it can be obtained with high purity and high yield, and the industrial value of the present invention is extremely high.

Applicant: Kuchigi Chemical Industry Co., Ltd.

Claims (7)

[Claims] (1) The following general formula ▲ Numerical formulas, chemical formulas, tables, etc. A quaternary phosphonium hydroxide aqueous solution represented by Characteristic high purity quaternary phosphonium hydroxide. (2) The high purity quaternary phosphonium hydroxide according to claim 1, wherein the concentration of the quaternary phosphonium hydroxide aqueous solution is 2 to 50 wt%. (3) In an electrolytic cell with a four-cell structure divided by an anion exchange membrane 1 and a cation exchange membrane 2 sandwiching it, there are the following general formulas ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_1 , R_2, R_3 and R_4 represent an alkyl group having 1 to 8 carbon atoms, an aryl group, an aralkyl group, or one in which at least one group thereof is substituted with a hydroxyl group or an alkoxyl group, and X^■ is A method for producing high-purity quaternary phosphonium hydroxide, which comprises obtaining quaternary phosphonium hydroxide from a cathode chamber by direct current electrolysis of a quaternary phosphonium salt aqueous solution represented by (indicating an anion). (4) In the manufacturing method according to claim 3, an acidic electrolyte solution is supplied to the anode chamber, water is supplied to the cathode chamber and the intermediate chamber on the anode side, and a quaternary phosphonium salt aqueous solution is supplied to the intermediate chamber on the cathode side. A method for producing high-purity quaternary phosphonium hydroxide, characterized by passing a direct current between the two. (5) Direct current electrolysis of the quaternary phosphonium salt aqueous solution is carried out at a temperature of 50° C. or lower, a current density of 1 to 50 A/dm^2, and a voltage of 1 to 50 V. A method for producing grade phosphonium hydroxide. (6) Supply concentration of quaternary phosphonium salt aqueous solution is 2 to 5
5. The method for producing high purity quaternary phosphonium hydroxide according to claim 3 or 4, wherein the content is 0 wt%. (7) The method for producing high-purity quaternary phosphonium hydroxide according to any one of claims 3 to 6, wherein the aqueous quaternary phosphonium salt solution is an aqueous tetraethylphosphonium bromide solution.