JPH075618B2 - Method for producing quaternary phosphonium fluorides - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a reaction of a fluorinating agent such as an aliphatic alcohol and a halide, an aromatic halide, a desilylating agent from a silylated compound, and an organic compound. The invention relates to a method for producing quaternary phosphonium fluorides having a wide range of uses as phase transfer catalysts and excellent properties.

[Conventional technology]

There are several known methods for producing quaternary phosphonium fluorides by conventional techniques. The outline of some of these conventional methods is as follows.

(A) Using quaternary phosphonium sulfate as a starting material, this was reacted with potassium hydrogen carbonate in a mixed solvent system of chloroform / water, and then 1 equivalent ratio of potassium hydrogen fluoride was added to the reaction solution. To produce a quaternary phosphonium bifluoride, or to add a large excess of potassium hydrogen fluoride to the reaction solution to react to produce a quaternary phosphonium trifluoride [Reference "Synthesis" No. See page 953 (1988)]. The reaction that occurs in this method can be represented by the following reaction formula.

(However, R is an n-butyl group, a phenyl group or tri-n-
A butyl-n-hexadecane group is shown).

(B) Tetraphenylphosphonium bromide was previously treated with an aqueous sodium hydroxide solution, and then the treated reaction solution was treated with hydrofluoric acid to form F ⁻ type, such as Amberlite IR 410, which was commercially available for ion exchange. Quantitative conversion to tetraphenylphosphonium bifluoride by passing through a resin-filled column [J. Chem. Soc. Chem. (J. Chem. Soc. Chem.
Commun.) Page 1256 (1983), and JP-A-61-161224). The reaction in this method can be represented by the following reaction formula.

(C) A method for producing tetraphenylphosphonium fluoride by neutralizing tetraphenylphosphonium bifluoride obtained by the above method (b) with sodium hydrogen carbonate in an aqueous solution [[Journal of.
Chemical Society Dalton Transactions (J. Chem. Soc. Dalton Trans.) P. 277 (1988)
reference〕. The reaction in this method can be represented by the following reaction formula.

[Problems to be Solved by the Invention] Of the above methods, according to the method (a), in order to obtain a quaternary phosphonium sulfate as a starting material,
Since the reaction must be carried out from the quaternary phosphonium bromide through a two-step process as shown in the following reaction formula [Synthesis, p. 508, (1985)], the operation of the method is complicated.

(However, R shows an alkyl group).

Moreover, in general, quaternary phosphonium fluorides having four alkyl groups on the phosphorus atom have high solubility in water, and therefore, a large amount of an organic solvent such as chloroform must be used for recovery from an aqueous reaction solution containing the quaternary phosphonium fluoride. Must be used and extracted. As a result, the volume yield deteriorates. In addition, the fluoride ion of the fluoride product may cause an exchange reaction with the chlorine atom of chloroform to contaminate the product.

Further, according to the above method (b), since fluoride salts are formed through exchange reactions with various ions, it is unavoidable that raw materials and intermediates such as bromine ions, sodium ions, and hydroxide ions are mixed.

Therefore, the conventional method is not always practical as an industrial manufacturing method. Therefore, there is a demand for the development of an industrially advantageous production method of the quaternary phosphonium fluorides as an alternative.

[Means for Solving the Problems] The inventors of the present invention have made diligent efforts to solve the above-mentioned problems. As a result, they have found a method for producing quaternary phosphonium fluorides in an aqueous solution at a low cost and in an extremely simple manner, in high yield and high purity, using quaternary phosphonium hydroxide as a starting material.

Therefore, according to the present invention, the following general formula (II) In the aqueous solution of the quaternary phosphonium hydroxide represented by the formula (wherein R represents an alkyl group), the quaternary phosphonium hydroxide is hydrofluoric acid of the following formula (III) HF (III). Phosphonium hydroxide 1
General formula (I), characterized in that the reaction is carried out at a ratio of 1 to 4 mol of HF per mol. (In the formula, R has the same meaning as described above, and n is an integer of 1, 2, 3 or 4)
A method for producing a fluoride is provided.

The reaction in the method of the present invention can be represented by the following reaction formula.

However, R and n have the same meanings as described above.

R in the compound of the general formula (I) represents a linear or branched alkyl group, particularly an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, and examples thereof include a methyl group and an ethyl group. It may be a group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, neopentyl group, hexyl group and the like.

Hereinafter, the method for producing the quaternary phosphonium fluoride of the present invention will be described in more detail.

It is known that the quaternary phosphonium hydroxide of the formula (II), which is a starting material, can be easily produced from a corresponding quaternary phosphonium halide as a high-purity product containing no halide ion by an ion exchange method (special feature: Kaisho
62-212397).

An aqueous solution containing 5 to 50% (by weight) of the quaternary phosphonium hydroxide of the formula (II) thus obtained was industrially available at a concentration of 45 to 55% (by weight) of hydrofluoric acid ( An aqueous solution of (HF) is added dropwise as HF at a ratio of 1 equivalent (stoichiometric amount). The equivalent point of this acid-base reaction is pH 8
Therefore, it is possible to identify the end point of the reaction by adding phenolphthalein as an indicator during this reaction and then adding hydrofluoric acid until the color changes from red to colorless.

The concentrations of the raw material compound (II) and the reactant HF are as described above.
However, the operability of the method is that the quaternary phosphonic compound of formula (II)
The concentration of um hydroxide aqueous solution is 10-40% (by weight)
preferable. The reaction temperature is 0 to 60 ° C, preferably 10 to 40 ° C.
preferable. Also, the dropping time of the aqueous solution of hydrofluoric acid (HF) is
It takes 10 minutes to 1 hour and matures for 30 minutes to 1 hour. Desired
If so, add hydrogen fluoride gas (H
F) can also be blown gently to react. Anti
After that, add water under reduced pressure at 10 to 200 ° C, preferably 30 to 60 ° C.
When distilled off, the following formula (R_FourP F ・ 3H₂Quaternary phosphonium represented by O
 Fluoride trihydrate can be produced quantitatively,
When the distillate is continuously distilled off, the redistribution reaction causes bifluoride.
And give phosphine oxide. Also, as mentioned above
Using exactly the same procedure, hydrofluoric acid (HF) was added to formula (II)
2 equivalents of HF to quaternary phosphonium hydroxide
Alternatively, 3 equivalents or 4 equivalent ratios are added and reacted, and then
When water is distilled off from the reaction solution under reduced pressure,
Quaternary phosphonium bifures represented by general formula (I)
Olide or quaternary phosphonium trifluoride or
Complete anhydrous quaternary phosphonium tetrafluoride
Quantitatively (wherein n is an integer of 2, 3 or 4)
Obtainable.

In the method of the present invention, the only by-product of these reactions is water, and the target compound of the formula (I) can be obtained in a very high purity.

〔Example〕

 The present invention will be specifically described below with reference to examples.

Example 1 Tetra-n-butylphosphonium fluoride 3 water
40.0 in a 500 ml four-necked flask equipped with a condenser and a stirrer.
% Concentration of tetra-n-butylphosphonium hydroxy
207.4 g (0.30 mol) of aqueous solution was added, and
Add 3-4 drops of Nolphthalein solution and cool to 10-15 ℃
I rejected it. Next, a hydrofluoric acid aqueous solution with a HF concentration of 47.0% was
The color of the indicator changed from red to colorless while keeping the temperature at 10 ~ 15 ℃
When added dropwise until it changed, 12.8 g (HF0.3
0 mol). After the dropping, stir at room temperature for 30 minutes.
After reacting at 40 ~ 50 ℃ under reduced pressure with an evaporator.
After distilling off the water and then dehydrating with a vacuum pump for 2 hours,
As 99.7g (Yield 99.9%, Purity 100%) of color transparent liquid
The following formula (n-C_FourH_{9 Four}P F ・ 3H₂The title compound, represented by O 2, was obtained. Of this obtained product
The analysis results are shown below.¹ H-NMR (CDCl₃), Δ (ppm): 1.00 (t, d = 6.5Hz, 12H), 1.52 (q, d = 6.5Hz, 16H), 2.10
~ 2.40 (m, 8H), 7.20 (br, s, 6H)¹⁹ F-NMR (CDCl₃), Δ (ppm): −125.5 (s) Example 2 Tetra-n-butylphosphonium bifluoride anhydrous
40.0 in a 500 ml four-necked flask equipped with a condenser and a stirrer.
% Concentration of tetra-n-butylphosphonium hydroxy
345.6 g (0.50 mol) of the aqueous solution was added, and the same procedure as in Example 1 was performed.
In this case, hydrofluoric acid with a HF concentration of 47.0% was added dropwise.
Discolored when 21.3 g (0.50 mol of HF) of HF solution was added
It became a point. Further add 1 equivalent ratio of hydrofluoric acid 2
Add 1.3 g (0.50 mol of HF) and stir for 30 minutes at room temperature.
I responded. Next, reduce the pressure from the reaction solution using an evaporator.
Water is distilled off at 40-50 ° C, and vacuum pump is used for 4-5 hours.
Upon dehydration, a colorless transparent liquid product (solid at room temperature
149.3 g (yield 100.0%, purity 100%) of the following formula (n-C_FourH_{9 Four}P F The title compound represented by (HF) was obtained. Analysis of the obtained product
The results are shown below.

Melting point: 30-35 ° C ¹ H-NMR (CDCl ₃ ), δ (ppm): 1.00 (t, d = 6.5Hz, 12H), 1.52 (q, d = 6.5Hz, 16H), 2.10
~ 2.40 (m, 8H), 13.90 (s, 1H) ¹⁹ F-NMR (CDCl ₃ ), δ (ppm): -155.6 (s) Elemental analysis Actual value: C 64.77%, H 12.12%, F 12.70%, P 10.41% Calculated value (as C ₁₆ H ₃₇ F ₂ P): C 64.38%, H 12.52%, F 12.73%, P 10.37% Example 3 Synthesis of tetra-n-butylphosphonium trifluoride anhydride Cooling tube, stirrer 40.0 in a 500 ml four-necked flask equipped with
% Tetra-n-butylphosphonium hydroxide aqueous solution (207.4 g, 0.30 mol) was added, and 47.0% HF hydrofluoric acid was added dropwise in the same manner as in Example 1 to react. When 12.8 g (HF0.30 mol) of was added, a color change point was formed. In addition, 25.5 g (0.60 mol of HF) of hydrofluoric acid having a ratio of 2 equivalents was added, and the mixture was reacted at room temperature for 30 minutes with stirring.

Then, the reaction solution was subjected to the same dehydration operation as in Example 2.
B, colorless and transparent liquid 95.6g (yield 100.0%, purity 100%)
As the following equation (n-C_FourH_{9 Four}P F ・ (HF)₂ The title compound indicated by was obtained.

The analysis results of the obtained product are shown below. ¹ H-NMR (CDCl ₃ ), δ (ppm): 1.00 (t, d = 6.5Hz, 12H), 1.52 (q, d = 6.5Hz, 16H), 2.10
~ 2.40 (m, 8H), 13.28 (br, s, 2H) ¹⁹ F-NMR (CDCl ₃ ), δ (ppm): -167.4 (s) Elemental analysis Actual value: C 60.62%, H 11.77%, F 17.90 %, P 9.71% Calculated value (as C ₁₆ H ₃₈ F ₃ P): C 60.33%, H 12.05%, F 17.90% P 9.72% Example 4 Synthesis of tetra-n-butylphosphonium tetrafluoride anhydride Cooling tube , In a 300 ml four-necked flask equipped with a stirrer, 40.
138.3 g (0.20 mol) of a 0% concentration tetra-n-butylphosphonium hydroxide aqueous solution was added, and 47.0% HF concentration of hydrofluoric acid was added dropwise in the same manner as in Example 1 to cause reaction. A color change point was reached when 8.5 g of an aqueous solution (0.20 mol of HF) was added. Further 3 equivalent ratio of hydrofluoric acid 2
5.5 g (0.60 mol of HF) was added and reacted at room temperature for 30 minutes with stirring.

Subsequently, dehydration operation of the reaction solution was performed in the same manner as in Example 2.
A colorless transparent liquid (67.7 g, yield 100.0%, purity 100)
%) As the following formula (n-C_FourH_{9 Four}P F ・ (HF)₃ The title compound indicated by was obtained.

The analysis results of the obtained product are shown below. ¹ H-NMR (CDCl ₃ ), δ (ppm): 1.00 (t, d = 6.5Hz, 12H), 1.52 (q, d = 6.5Hz, 16H), 2.10
~ 2.40 (m, 8H), 13.00 (br, s, 3H) ¹⁹ F-NMR (CDCl ₃ ), δ (ppm): -145.8 Elemental analysis Found: C 56.70%, H 11.78%, F 22.42%, P 9.10% Calculated value (as C ₁₆ H ₃₉ F ₄ P): C 56.76%, H 11.64%, F 22.45% P 9.15% Next, reference examples of preparation of raw material compounds used in Examples 1 to 4 Indicate.

Reference Production Example Production of tetra-n-butylphosphonium hydroxide (an example of raw material compound (II)) Amberlite IRA-400 (Cl fully swollen in water
Type: Organo product) 150 ml is packed in a column with an inner diameter of 25 mm.

Then, add 390 g (975 mmol) of 10% aqueous sodium hydroxide solution to 4
The resin was converted to the OH form by passing it through at a flow rate of ml / cm ² / min and the resin was washed with deionized water until the eluent was neutral.

Tetra-n-butylphosphonium bromide 28.0 g (8
2.5 mmol) is dissolved in 112 ml of deionized water, and this aqueous solution is passed through a column, and then flushed with deionized water to obtain a main fraction containing a large amount of the target tetra-n-butylphosphonium hydroxide, about 180 ml. Was collected.

This main fraction, an aqueous solution, is diluted with 180 ml of dichloromethane
It was extracted twice and unreacted tetra-n-butylphosphonium bromide was extracted and removed. A small amount of dichloromethane remaining in the aqueous solution after extraction was distilled off under reduced pressure to obtain 180 ml of a highly pure tetra-n-butylphosphonium hydroxide aqueous solution (concentration: 0.375 mol / l, yield: 8
1.8%).

The amount of unreacted tetra-n-butylphosphonium bromide contained in this solution was a trace amount. Incidentally, unreacted tetra-n-butylphosphonium bromide 3.3 g (recovery rate 11.8%) was recovered from the dichloromethane extract.

Next, the usefulness of the compound of formula (I) obtained by the method of the present invention will be specifically described with reference to Reference Examples 1 and 2.

Reference Example 1 Fluorination with tetra-n-butylphosphonium bifluoride 4.5 g tetra-n-butylphosphonium bifluoride
(15 mmol), 0.8 g (5 mmol) of p-chloronitrobenzene and 5 ml of xylene are mixed to make a homogeneous solution. The mixture was heated at 140 ° C. for 2 hours to complete the fluorination reaction of p-chloronitrobenzene. The reaction solution was washed with water and post-treated, and as a result of internal standard analysis by gas chromatography, 0.63 g of p-fluoronitrobenzene (yield 90%)
Got

Reference Example 2 Desilylation with tetra-n-butylphosphonium trifluoride Tetra-n-butylphosphonium trifluoride 3.
A homogeneous solution of 2 g (10 mmol), 2-tetradecanol tert-butyldiphenylsilyl ether 2.3 g (5 mmol) and tetrahydrofuran 3 ml was reacted at 45 ° C. for 48 hours, and the elimination of tert-butyldiphenylsilyl group was observed. Then, 1.07 g of 2-tetradecanol (yield 100%) was obtained.

〔The invention's effect〕

According to the method of the present invention, the quaternary phosphonium fluorides can be industrially extremely easily produced with the following features.

That is, first, it is possible to obtain the corresponding fluorides in a high yield and very easily by a simple operation in which 1 to 4 equivalents of hydrofluoric acid are allowed to act on an easily available quaternary phosphonium hydroxide in an aqueous solution. You can

Secondly, compared with the conventional method, since the target anion can be led to the target product without performing multi-step ion exchange, impurities such as counter anions are not mixed in the target product at all, and by-products are generated in the reaction. Since only water is used, the desired product can be obtained quantitatively with extremely high purity.

Thirdly, the obtained quaternary phosphonium fluorides have high purity and excellent solubility in various solvents,
It has excellent properties such that it can be advantageously used as a fluorinating agent for aliphatic and aromatic compounds, a desilylating agent, and a phase transfer catalyst, and is industrially very useful.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akiki Qian, 2-1, Hirosawa, Wako-shi, Saitama, RIKEN (72) Inventor Yukitaka Uchibori, 5214 Tamura, Hiratsuka-shi, Kanagawa Prefectural public corporation Tamura apartment 552 ( 72) Inventor Masayuki Umeno 521-3 Chigasaki, Chigasaki City, Kanagawa Prefecture

Claims (1)

[Claims] 1. The following general formula (II): In the aqueous solution of the quaternary phosphonium hydroxide represented by the formula (wherein R represents an alkyl group), the quaternary phosphonium hydroxide is hydrofluoric acid of the following formula (III) HF (III). Phosphonium hydroxide 1
General formula (I), characterized in that the reaction is carried out at a ratio of 1 to 4 mol of HF per mol. (In the formula, R has the same meaning as described above, and n is an integer of 1, 2, 3 or 4)
Method for producing fluorides.