JPH0145477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides diphenylphosphinobenzene-m-
The present invention relates to a method for producing a monosulfonate.
The sodium, potassium, or lithium salts of diphenylphosphinobenzene-m-monosulfonic acid are water-soluble trisubstituted phosphines that stabilize metal catalysts in various catalytic reactions and dissolve catalyst components in aqueous solvents. This is a very interesting compound in that it makes it possible to separate the solution containing the product and the catalyst. this house,
It has already been shown that the sodium salt of diphenylphosphine-m-monosulfonic acid can be synthesized by sulfonating triphenylphosphine in fuming sulfuric acid and contacting the reaction mixture with an aqueous sodium hydroxide solution. It is publicly known [J.
Chem.Soc., (1958), 276]. However, in the method described in the literature, diphenylphosphinobenzene-
Only the sodium salt of m-monosulfonic acid is obtained in a low yield of 32.7%. When this method is viewed from an industrial perspective, it has the following problems.

1 Increasing the conversion rate of triphenylphosphine to nearly 100% in the sulfonation process increases the amount of corresponding disulfonic acid and trisulfonic acid by-products due to sequential reactions, resulting in substantial loss of expensive triphenylphosphine. Not only this, but also the separation and purification of the target sodium monosulfonate becomes extremely complicated, and as a result, the isolation yield of the monosulfonate salt decreases.

2. Since the concentrated sulfuric acid used in the reaction is directly neutralized with sodium hydroxide, not only a large amount of sulfuric acid and sodium hydroxide are lost, but also a large amount of heat is generated, resulting in poor operability. Furthermore, it is difficult to separate sodium monosulfonate from a large amount of sodium sulfate produced by neutralization.

3. Since the lithium salt of diphenylphosphinobenzene-m-monosulfonic acid has extremely high solubility in water and an aqueous lithium sulfate solution, it is difficult to apply the method described in the literature to the synthesis of the lithium salt.

From this background, the present inventors have conducted intensive studies on a method for producing diphenylphosphinobenzene-m-monosulfonate suitable for industrial implementation.
As a result, triphenylphosphine is sulfonated by reacting with sulfuric anhydride in concentrated sulfuric acid within a range where the conversion rate of triphenylphosphine is 10 to 80% (step), and the reaction mixture obtained in step () is Add water to the reaction mixture to increase the sulfuric acid concentration to 40% by weight.
After the following, diphenylphosphinobenzene-m-monosulfonic acid and unreacted triphenylphosphine were extracted with 4-methyl-2-pentanone by extraction with 4-methyl-2-pentanone.
Extract and separate into pentanone layer (process), process ()
The 4-methyl-2-pentanone layer obtained in is contacted with an aqueous solution of a hydroxide, carbonate or bicarbonate of a metal selected from the group consisting of sodium, potassium and lithium to produce diphenylphosphinobenzene-m. - After the monosulfonate is transferred to the aqueous layer, the diphenylphosphinobenzene-m-monosulfonate is recovered from the aqueous layer (step), whereby diphenylphosphinobenzene-m-monosulfonic acid is recovered. The inventors have discovered that salts can be produced in high yield, and have completed the present invention. The method of the present invention has an extremely high isolation yield of diphenylphosphinobenzene-m-monosulfonate based on the reacted triphenylphosphine, unreacted triphenylphosphine, and by-produced triphenylphosphine. Easy separation of disulfonate and trisulfonate salts of enylphosphine and their reuse; no sulfuric acid neutralization step is required; sulfuric acid can be reused; and sulfuric acid can be neutralized. It has the advantages of not requiring an alkali for the reaction, that the process is simple, and that not only the sodium salt but also the potassium salt and lithium salt of sulfonic acid can be easily produced.

The sulfonation of triphenylphosphine according to the process of the invention is carried out by reacting triphenylphosphine with sulfuric anhydride in concentrated sulfuric acid. This reaction is usually carried out at -10°C to 100°C, preferably at 0°C.
It is carried out at a temperature of ~40°C. Although the reaction rate increases as the reaction temperature increases, there is a tendency for the by-product of phosphine oxide to increase. As the sulfuric anhydride source, known sulfuric anhydride sources such as sulfuric anhydride (SO ₃ ), a sulfite solution of sulfuric anhydride, chlorosulfonic acid, and fuming sulfuric acid can be used as they are. It is practical to select the molar ratio of sulfuric anhydride to triphenylphosphine within the range of 0.1 to 10, preferably 1 to 5. By carrying out the sulfonation of triphenylphosphine within a range where the conversion rate of triphenylphosphine is 10 to 80%, preferably 20 to 60%, the disulfonic acid and trisulfonic acid of triphenylphosphine can be reduced. Since the production of triphenylphosphine is suppressed, the substantial loss of expensive triphenylphosphine can be minimized. When the conversion rate of triphenylphosphine exceeds 80%, the amount of by-products of disulfonic acid and trisulfonic acid increases, and the yield of monosulfonic acid decreases, which is industrially disadvantageous. Also, the conversion rate of triphenylphosphine is 10%.
When the amount is less than 1, the yield of monosulfonic acid obtained in one reaction operation is low and is not practical.

The reaction mixture obtained in step () is
The sulfuric acid concentration is 40% by weight or less, preferably 10% by weight.
Diluted with water to ~30% by weight. If the sulfuric acid concentration exceeds 40% by weight, 4-methyl-2-
Not only does the extraction efficiency of diphenylphosphinobenzene-m-monosulfonic acid with pentanone decrease, but it also becomes difficult to separate diphenylphosphinobenzene-m-monosulfonic acid from disulfonic acid, trisulfonic acid, and sulfuric acid. . There is no critical lower limit for sulfuric acid concentration, but approximately 5% by weight
If it is below, a large amount of steam is required to recover disulfonic acid, trisulfonic acid, and sulfuric acid from the aqueous layer, which is economically disadvantageous. The reaction mixture diluted with water is subjected to an extraction operation with 4-methyl-2-pentanone. Through this extraction operation, a part of the disulfonic acid, monosulfonic acid and unreacted triphenylphosphine are removed from 4-methyl-
The 2-pentanone layer and most of the disulfonic acid and trisulfonic acid are extracted and separated into the aqueous layer (sulfuric acid aqueous solution). After water is distilled off from the aqueous layer, the residue containing disulfonic acid and trisulfonic acid is recycled to the sulfonation step of step (), where the disulfonic acid and trisulfonic acid are converted to monosulfonic acid by a disproportionation reaction. Can be converted to acid.

After washing the 4-methyl-2-pentanone layer obtained in step () with a small amount of water as necessary,
In step (), the 4-methyl-2 - Transfer the sulfonic acids contained in the pentanone layer to the aqueous layer side as the corresponding sulfonate. In this case, there are no special restrictions on the amount of water in the system, but generally the amount of water is such that the sulfonate is heated to about 100°C.
It is preferable that the amount is necessary so as not to exceed the saturation solubility in water. 4-Methyl-2- containing unreacted triphenylphosphine
After washing the pentanone layer with water as necessary,
-4- by distillation from the methyl-2-pentanone layer
Methyl-2-pentanone is recovered. Triphenylphosphine recovered as a distillation residue is recycled as it is or after being purified by recrystallization and recycled to the sulfonation step of step () for reuse.
The monosulfonate contained in the aqueous layer can be isolated by distilling off water, and a highly purified sulfonate can be further isolated as follows. In other words, according to detailed studies by the present inventors, it was found that the solubility of monosulfonic acid sodium and potassium salts in water has an extremely large temperature dependence. By applying this method, a highly purified sodium salt or potassium salt of monosulfonic acid can be isolated in high yield. If necessary, it can be purified by repeated recrystallization operations from water. In addition, the lithium salt of monosulfonic acid can be obtained by distilling water off from the aqueous layer, and if necessary, 4-methyl-2-pentanone, n-butyl acetate, diphenyl ether or diphenyl ether can be obtained. Its purity can be increased by recrystallization from a mixed solvent of enyl ether and an aromatic hydrocarbon such as toluene, xylene, or diphenyl.

The method of the present invention will be specifically explained below using Examples.

Example 1 80 g (0.3 mol) of triphenylphosphine and 36 g of concentrated sulfuric acid were charged into a 500 ml four-neck flask equipped with a thermometer, stirring device, dropping funnel, and nitrogen gas inlet and outlet, and the system was replaced with nitrogen gas. At the same time, the mixture was heated until the internal temperature reached 30°C. Add 20wt of SO ₃ to this mixture while stirring while keeping the internal temperature at 30℃.
% of fuming sulfuric acid was added dropwise over 30 minutes.
After the addition of the fuming sulfuric acid was completed, stirring was continued at 30°C for 3 hours. A small amount of the reaction mixture was taken out and the unreacted triphenylphosphine contained therein was analyzed by iodometry, and the conversion rate of triphenylphosphine was 60%. approximately 20 wt.% by adding approximately 1500 ml of ice water to the reaction mixture while cooling.
was made into an aqueous sulfuric acid solution. 1 in sulfuric acid aqueous solution after dilution with water
A total of two extraction operations were performed using 700 ml of 4-methyl-2-pentanone per extraction. After making the entire system neutral (requiring about 150 ml of sodium hydroxide aqueous solution) by adding approximately 4 wt% sodium hydroxide aqueous solution to the 4-methyl-2-pentanone layer, the system was heated to 80°C. Aqueous layer and 4-methyl-2
- The liquid was separated into a pentanone layer. 4-methyl-2-
When 4-methyl-2-pentanone was distilled off from the pentanone layer using a rotary evaporator, 31 g of unreacted triphenylphosphine was recovered. On the other hand, when the aqueous layer was cooled to 15°C, white crystals were precipitated. Crystals were collected by filtration. After the liquid was concentrated by about 3 times by distilling off water using a rotary evaporator, it was cooled to 15°C, and white crystals were precipitated. Crystals were collected by filtration. The collected crystals were dissolved in distilled water and recrystallized from the resulting aqueous solution. Finally, 45 g of white crystals were obtained.
When this crystal was analyzed by elemental analysis, iodometry, and liquid chromatography, it was found that 98.5 wt.% of sodium diphenylphosphinobenzene-m-monosulfonate dihydrate was present in the crystal.
It was found that 1.5 wt.% of the corresponding sodium disulfonate tetrahydrate was contained.

Example 2 The sulfonation reaction of triphenylphosphine was carried out for a total of 2.5 hours under the same conditions and operations as in Example 1. The conversion rate of triphenylphosphine after 2.5 hours was 40%. The reaction mixture was diluted with ice water to make a 25 wt.% sulfuric acid aqueous solution, and then 700 ml of 4-methyl-2 was added at each time.
-The same extraction operation as in Example 1 was carried out using pentanone. After making the entire system neutral by adding about 4 wt.% aqueous lithium hydroxide solution to the 4-methyl-2-pentanone layer at room temperature, both layers were separated. When 4-methyl-2-pentanone was distilled off from the 4-methyl-2-pentanone layer, 45.2 g of unreacted triphenylphosphine was recovered. Most of the water contained in the aqueous layer is distilled off using a rotary evaporator, and the remaining liquid contains 4-methyl-
400 ml of 2-pentanone was added, the remaining water was distilled off by azeotropic distillation, and 4-methyl-2-pentanone was further distilled off, yielding 40.5 g of a white precipitate. When this white crystal was analyzed in the same manner as in Example 1, it was found that the white crystal was 98 wt.% of lithium diphenylphosphinobenzene-m-monosulfonate monohydrate and the corresponding lithium disulfonate dihydrate. It was concluded that it was a mixture of 2 wt.% hydrate.

Example 3 The sulfonation reaction of triphenylphosphine was carried out for a total of 2.75 hours under the same conditions and operations as in Example 1. The conversion rate of triphenylphosphine after 2.75 hours was 45%. The reaction mixture was diluted with ice water to obtain a 20 wt.% sulfuric acid aqueous solution, and then 4-methyl-2- as in Example 1 was prepared.
Pentanone extraction was performed. The entire system was made neutral by adding about 5 wt.% aqueous potassium carbonate solution to the 4-methyl-2-pentanone layer at room temperature, and then both layers were separated. The aqueous layer was recrystallized in the same manner as in Example 1, and the final purity was 99%.
43 g of potassium diphenylphosphinobenzene-m-monosulfonate dihydrate was obtained.

Claims (1)

[Scope of Claims] 1 () Triphenylphosphine in concentrated sulfuric acid with a conversion rate of 10 to 80
% by reaction with sulfuric anhydride, and () add water to the reaction mixture obtained in step () to bring the sulfuric acid concentration in the reaction mixture to 40% by weight.
After the following, by performing an extraction operation with 4-methyl-2-pentanone, diphenylphosphinobenzene-m-monosulfonic acid and unreacted triphenylphosphine were converted into a 4-methyl-2-pentanone layer. Extract and separate, () 4-methyl-2- obtained in step ()
Diphenylphosphinobenzene produced by contacting the pentanone layer with an aqueous solution of hydroxide, carbonate or bicarbonate of a metal selected from the group consisting of sodium, potassium and lithium.
Diphenylphosphinobenzene-m-monosulfonic acid, characterized in that the m-monosulfonate is transferred to an aqueous layer, and then the diphenylphosphinobenzene-m-monosulfonate is recovered from the aqueous layer. Salt manufacturing method. 2. The method according to claim 1, wherein the conversion rate of triphenylphosphine in step () is 20 to 60%. 3. The method according to claim 1, wherein in step (), the reaction mixture is diluted with water until the sulfuric acid concentration in the reaction mixture becomes 10 to 30% by weight. 4 In step (), the 4-methyl-2-pentanone layer is brought into contact with an aqueous solution of sodium hydroxide or potassium hydroxide, and the resulting sodium salt or potassium salt of diphenylphosphinobenzene-m-monosulfonic acid is added to the aqueous layer. After the transfer, the sodium or potassium salt of diphenylphosphinobenzene-m-monosulfonic acid is recovered from the aqueous layer by a recrystallization operation, and 4-methyl-2-pentanone is distilled from the 4-methyl-2-pentanone layer. The method according to claim 1, wherein unreacted triphenylphosphine is recovered by removing the unreacted triphenylphosphine. 5. In step (), the 4-methyl-2-pentanone layer is brought into contact with an aqueous lithium hydroxide solution, and the resulting lithium salt of diphenylphosphinobenzene-m-monosulfonic acid is transferred to the aqueous layer.
Diphenylphosphinobenzene-m-monosulfonic acid was obtained by distilling off water from the aqueous layer, and 4-methyl-2-pentanone was obtained by distilling off from the 4-methyl-2-pentanone layer. The method according to claim 1, wherein unreacted triphenylphosphine is recovered.